Search

Radiative cooling is promising in meeting the current global demand for green sustainable development. However, the effective cooling of the existing radiant cooler will be limited due to the serious solar energy absorption and poor thermal insulation performance on the cold side. To addresss these issues, we propose herein a novel composite material of silicon dioxide (SiO 2) aerogel microspheres combined with polyvinylidene fluoride-cohexafluoropropylene (PVDF-HFP) nanofiber membrane, in which SiO 2 aerogel microspheres are firstly synthesized by sol-gel method and then incorporated into PVDF-HFP nanofiber membrane to give radiative cooling performance. As we expected, the molecular vibration characteristics of PVDF-HFP nanofiber membrane and the phonon polarization resonance of Si-O-Si bond in the transparent window can enhance the infrared emissivity of the membrane surface. In addition, the high porosity and the mesoporous structure formed by the interconnection of nano-network skeletons of SiO 2 aerogel microspheres determine its excellent thermal insulation performance. The as-prepared material displays that the average solar reflectance of the composite membrane is 96.07 % and the average infrared emissivity of the atmospheric window is 94.95 %. Notably, when the average solar radiation intensity is 885.56 W•m−2, the passive radiative cooling temperature during the day can reach 11.2 °C. Furthermore, this material has excellent self-cleaning and thermal insulation performance, making it a potential radiant cooling candidate in many fields. [ABSTRACT FROM AUTHOR]

Barium titanate doped with calcium and zirconium (BCZT) relaxor ferroelectric ceramics enhance energy storage capabilities due to their excellent ferroelectric and dielectric properties. In this investigation, BCZT particles (Ps) were incorporated into poly (vinylidene fluoride- co -hexafluoropropylene) (PVDF-HFP) using the solvent casting method to prepare biocompatible composite films with varying BCZT Ps contents. The uniform dispersion and distribution of BCZT Ps throughout the polymer matrix results in robust interfacial interactions, promoting improved nucleation of the β-phase in PVDF-HFP and increased thermal stability with higher BCZT Ps loading. The Young's modulus and tensile strength of the composites experienced respective increases of 78.2 % and 41.8 % with the addition of 20 wt% BCZT Ps. While the dielectric constant was improved from 12 to 31. This research contributes to the development of flexible composite films with different BCZT Ps contents, to promote an innovative and environmentally friendly energy harvesting technology. This innovation captures environmental vibrations and converts them into electrical energy to supply a variety of sensors. [ABSTRACT FROM AUTHOR]

An innovative approach has been adopted through the synthesis of a cost‐effective ferroelectric host polymer, which was integrated with Barium Titanate (BaTiO3) to develop an efficient electrospun Polyvinylidene Fluoride‐Hexafluoropropylene/BaTiO3 (PVdF‐HFP/BaTiO3) nanocomposite (PBT), designated for energy harvesting and piezocatalytic applications. FT‐IR affirmed the existence of the crystalline β‐phase within the nanofibers. SEM images showed that nanofiber diameter decreases as applied voltage is increased in electrospinning. The BaTiO3 nanoparticles were scattered evenly in PBT, but at lower voltages, they aggregate. PBT showed enhanced piezoelectric performance under higher voltage conditions, registering a maximum piezoelectric output of ~7.7 V and an output current of 0.77 μA. Moreover, the composite exhibited a power density of 14.15 mW/m2 at a load resistance of 20 MΩ. Fabricated piezoelectric nanogenerator (PENG) demonstrated practical utility in flexible electronics, notably in charging capacitors of 0.47 μF and 1 μF. Additionally, the piezocatalytic degradation of the antibiotic ciprofloxacin (CIP) was effectively achieved using the electrospun nanofibers, with an impressive degradation rate of up to 99.6 % within 30 minutes under acidic conditions, and the material displayed notable reusability, maintaining up to 95.5 % efficiency after five cycles. DFT calculations and COMSOL simulations alongside a comparative examination of the electronic properties of PBT. [ABSTRACT FROM AUTHOR]

Energy storage devices play a crucial role in all kinds of electronic devices. Rechargeable lithium-ion batteries have run across problems such as energy density, toughness, and safety. In order to conquer these hindrances, in this work, a novel solid-state polymer electrolyte for lithium-ion batteries was synthesized by blending polymethyl methacrylate (PMMA) in poly (vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) with constant weight percent of ethylene carbonate (EC) and lithium bis (trifluoro methane sulfonyl) imide (LiTFSI), and different concentrations of calcium oxide (CaO). The composite polymer electrolytes (CPEs) (PVdF-HFP:PMMA:LiTFSI:EC:CaO) were fabricated using the solution casting technique. Powder XRD reveals enhancement in intensity with increasing CaO content. FTIR shows the interaction between the polymer-salt matrix. Among the analyzed films, PVdF-HFP:PMMA:LiTFSI:EC:CaO (10 wt.%) exhibits high ionic conductivity (10–4 S/cm) and good electrochemical (4 V) and thermal stability (350℃) which makes it suitable for solid-state electrolyte as a separator in energy storage applications. [ABSTRACT FROM AUTHOR]

This work focuses on the development of a composite polymer electrolyte (CPE) for all‐solid‐state lithium metal batteries (ASSLMBs), integrating LLTO nanofibers into a PEO (polyethylene oxide)‐PVDF‐HFP (poly(vinylidene fluoride‐cohexafluoropropylene)) matrix with LiClO4 as the lithium salt. The PEO has high ionic conductivity and flexibility, and the PVDF‐HFP has high mechanical strength and electrochemical stability. Therefore, the resulting composite has improved electrochemical performance and mechanical properties. Incorporating LLTO nanofibers enhances ionic conductivity due to the one‐dimensional ion transport pathways provided by the nanofibers while maintaining mechanical integrity and air stability, overcoming the challenges associated with conventional fillers. The prepared CPE demonstrates exceptional electrochemical stability up to 5.1 V versus Li/Li+, making it suitable for high‐voltage applications over traditional polymer electrolytes. The optimized CPE with 15 wt% LLTO provides the ionic conductivity of 1.1 × 10−5 S cm−1 at room temperature and reaches 1.46 × 10−4 S cm−1 at 80°C. The assembled LiNi1/3Mn1/3Co1/3PO4||PEO‐PVDF‐HFP‐LiClO₄‐LLTO||Li based 2032 coin cell worked in between 3 and 4.8 V versus Li/Li+ potential window without any electrolyte decomposition from 0.5 to 5 mV/s scan rates. Similarly, the fabricated LiFePO₄||PEO‐PVDF‐HFP (1:2)‐LiClO4‐LLTO (15 wt%)||Li cell provides an initial capacity of 149 mAh g−1 at 0.1 C and 85 mAh g−1 at 0.5 C, exploring its potential for lithium metal batteries. Overall, this work offers a promising pathway for developing advanced solid polymer electrolytes for next‐generation lithium metal batteries, which combine high ionic conductivity, excellent electrochemical performances, and robust mechanical properties. [ABSTRACT FROM AUTHOR]

A salient bottleneck to driving the wider use of polyvinylidene fluoride (PVDF) and its copolymers in smart applications is the requirement for a high-voltage poling process required to activate their $\beta $β-phase crystal structure before the realisation of the piezoelectricity response. In pursuit of enhancing the β-phase content of PVDF-based films, various approaches have been employed in recent years. Yet, a perfect solution to the challenge remains elusive. Here, we report a preliminary investigation into the production of unpoled poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) films reinforced with barium titanate (BaTiO3) and activated carbon (AC) to improve the piezoelectric property. Employing the mixture design of experiments (MDOE) method, various formulations of the composite’s constituents weight fractions were determined. Afterwards, series of composite films were produced via a toxic-free solution casting method and characterised by Fourier Transform Infrared Spectrum (FTIR) to determine the β-phase content. A non-linear polynomial regression model was established from the experimental FTIR data, and the adequacy of the model was confirmed using ANOVA. Subsequently, an MDOE-enabled optimisation was undertaken, generating a formulation of the composite to obtain the highest β-phase content to be $15$15 wt.% BaTiO3 and $0.74$0.74 wt.% AC. This combination produces a theoretically predicted β-phase content of $72.7$72.7%. A further experimental test employing the optimal formulation produced a β-phase content of $71.90$71.90%, achieved with neither mechanical stretching, thermal annealing, nor electrical poling. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ternary composite membranes have been developed for battery separator applications. • Membranes have been developed by varying silver nanowires and titanium dioxide nanoparticle content. • Ternary composites show improved mechanical and electrochemical responses. • An ionic conductivity > 10−4 S/cm has been obtained independently of the filler type and content. • The highest discharge capacity value has been obtained for the 5 wt% AgNWs/5 wt% TiO 2 /PVDF-HFP membranes. In the realm of polymer composites, there is growing interest in the use of more than one filler for achieving multifunctional properties. In this work, a composite separator membrane has been developed for lithium-ion battery application, by incorporating conductive silver nanowires (AgNWs) and titanium dioxide (TiO 2) nanoparticles into a poly(vinylidene fluoride- co -hexafluoropropylene) (PVDF-HFP) polymer matrix. The composite membranes were manufactured by solvent casting and thermally induced phase separation, with total filler content varying up to 10 wt%. The ternary composites composites present improved mechanical characteristics, ionic conductivity and lithium transfer number compared to the neat polymer matrix. On the other hand, the filler type and content within the composite has little bearing on the morphology, polymer phase, or thermal stability. Once applied as a separator in lithium-ion batteries, the highest discharge capacity value was obtained for the 5 wt% AgNWs/5 wt% TiO 2 /PVDF-HFP membrane at different C-rates, benefiting from the synergetic effect from both fillers. This work demonstrates that higher battery performance can be achieved for next-generation lithium-ion batteries by using separator membranes based on ternary composites. [ABSTRACT FROM AUTHOR]

Membrane wetting caused by substances in the feed solution with low surface tension has posed serious issues for membrane distillation (MD). Omniphobic membranes could be helpful when dealing with this problem because they strongly repel liquids with a wide range of surface tensions. We fabricated electrospun omniphobic membranes containing PVDF‐TEOS‐PFDTMS, PVDF‐HFP‐TMOS‐PFDTMS, and PVDF‐HFP‐TEOS‐PFDTMS. All electrospun membranes have shown contact angles >90°, but the electrospun membrane containing PVDF‐HFP‐TEOS‐PFDTMS has shown super repellence with a contact angle >150° and maintains stable salt rejection and water flux in direct contact MD processes in the presence of sodium dodecyl sulfate surfactant (up to 0.3 mM). Furthermore, the morphology and crystallinity of the electrospun membranes were studied by scanning electron microscopy and Fourier‐transform infrared spectroscopy, and the percentage composition of elements was analyzed by x‐ray photoelectron spectroscopy. liquid entry pressure, mechanical strength, and the porosity of the electrospun omniphobic membranes were also studied. [ABSTRACT FROM AUTHOR]

The present study investigates the influence of photosensitizer selection and the polymer electrolyte composition on the performance of quasi-solid-state dye-sensitized solar cells (QsDSSCs). Two benchmark ruthenium dyes, N719 and Z907, alongside a novel photoactive phenothiazine dye were used. Each dye was incorporated into a QsDSSC architecture employing poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) as the gel electrolyte matrix, with varying molecular weights, to investigate their impacts on the overall device performance and long-term stability. Our results demonstrated that the N719 dye exhibited the highest power conversion efficiency (PCE), attributed to its strong absorption in the visible spectrum and efficient electron injection into the TiO2 photoanode. Z907, on the other hand, showed moderate PCE due to its broader absorption profile but slower electron injection kinetics. The phenothiazine dye revealed promising PCE, with tunable absorption properties and efficient charge transfer. Furthermore, the impact of PVDF-HFP polymer gel electrolytes with varying molecular weights on cell stability was explored. The QsDSSC incorporating the PVH80 polymer with the phenothiazine dye exhibited reduced dye desorption, due to the effective dye molecules' immobilization by the gel matrix, and consequently enhanced long-term stability over 600 h. This comparative study sheds light on the interplay between dye selection, the polymer gel's properties, and QsDSSCs' performance. These insights are crucial in designing robust and efficient QsDSSCs for practical applications. [ABSTRACT FROM AUTHOR]

Highlights Flexible sensors, made of PVDF‐HFP reinforced with carbon nanotubes (CNTs), are manufactured by solvent casting. More specifically, the effect of evaporation temperature and sonication time is explored. It is seen that two effects govern the dispersion of CNT: the sedimentation half‐time, and the breakage induced by the ultrasonication process. In this regard, it is found that 60°C is an optimum evaporation temperature to reach the highest value of electrical conductivity, since it offers a good balance between these effects, leading to the creation of a more efficient electrical network. This is also confirmed by the AC analysis, where these samples show the highest characteristic frequencies. The electromechanical results show a greater dependency on evaporation temperature for low sonication times, as the breakage induced by an ultrasonic process is not so pronounced and, therefore, the sedimentation effect plays a more dominant role. In addition, cycling tests show robust electromechanical response with cycling, and creep tests prove good electrical response of the sensors, less than 200 ms in some cases. Finally, proof of concept testing of wrist, shoulder, and neck monitoring highlights the potential of the proposed materials for sensing applications. PVDF‐HFP/CNT nanocomposite strain sensors via solvent casting are proposed. The effect of evaporation temperature and sonication time is studied. DC and AC conductivities were analyzed and modeled via an equivalent circuit. An outstanding Gauge Factor of 86.30 × 104 is achieved at 95% of strain level. Two proof‐of‐concepts of medium and large movements are successfully achieved. [ABSTRACT FROM AUTHOR]

Cellulose has advantages of easy availability, low price, renewability and biodegradability, making it a very promising substitute for fossil-based materials. A safe composite cellulose membrane for quasi-solid-state lithium ion batteries has been developed by coating cellulose separators with poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and lithium aluminum titanium phosphate (LATP). This membrane exhibits excellent electrochemical performance, with an ionic conductivity as high as 2.1 mS cm−1, and a lithium-ion transference number of 0.57. The membrane shows good electrolyte wetting properties, with porosity and liquid electrolyte uptake of 47.2 % and 401.7 %, respectively. It has good thermal stability and can maintain its dimensional stability even at 200 ℃. The capacity retention of the quasi-solid-state LiFePO4/Li battery assembled with this membrane after 200 cycles at 0.2 C is about 86.7 %. The quasi-solid-state battery has good thermal stability and is not prone to thermal runaway.

Abstract This study is the first application of a PVDF-HFP-based polymer inclusion membrane incorporating the poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and di(2-ethylhexyl)phosphoric acid (D2EHPA) as the base polymer and extractant for the extraction of bismuth(III), respectively. It is demonstrated that the PIM comprised of 60 wt% PVDF-HFP and 40 wt% D2EHPA is the most effective in the extraction of bismuth(III) from feed solution containing 20 mg L−1 bismuth(III) and 0.2 mol L−1 sulfate adjusted to pH 1.4. The extracted bismuth(III) ions are back-extracted quantitatively to the receiving solution containing 1 mol L−1 sulfuric acid. The stoichiometry experiments reveal that the Bi: D2EHPA ratio in the bismuth(III) extracted complex is 1:6, and D2EHPA is dimer. Moreover, it is shown that the studied PIM has high selectivity in the extraction of bismuth(III) over other interfering ions such as Mo(VI), Cr(III), Al(III), Fe(III), Ni(II), Zn(II), Cd(II), Co(II), Cu(II), and Mn(II). The interference of Fe(III) is also eliminated by masking with fluoride, leading finally to a nearly pure extraction of bismuth(III).

High piezoelectric composite films composed of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and ferromagnetic cobalt ferrite (CoFe2O4) (0.00 ​wt% to 0.2 ​wt%) are prepared by a solution casting method accompanied by uniaxial stretching and high electric field poling. The decisive effect of the poling electric field on the power generating capability was confirmed by the experiments. For pure PVDF-HFP films, when the maximum electric field Emax is 120 ​MV/m, the calibrated open circuit voltage reaches 2.93 ​V, which is much higher than those poled at lower electric fields (70 ​MV/m: 1.41 ​V; 90 ​MV/m: 2.11 ​V). Furthermore, the addition of CoFe2O4 also influences the piezoelectricity dramatically. In the samples containing 0.15 ​wt% CoFe2O4, the calibrated open circuit voltage increases to the maximum value of 3.57 ​V. Meanwhile, the relative fraction of the β-phase and the crystallinity degree are 99% and 48%, respectively. The effects of CoFe2O4 nanoparticles on initial crystallization, uniaxial stretching and high electric field poling are investigated by XRD, FTIR and DSC.

Fouling and biofouling remain significant challenges in seawater desalination plants. One practical approach to address these issues is to develop anti-biofouling membranes. Therefore, novel hybrid zinc phthalocyanine/polyvinylidene fluoride-co-hexafluoropropylene (Zn(4-PPOx)4Pc/PVDF-HFP) membranes were prepared by electrospinning to evaluate their properties against biofouling. The hybrid nanofiber membrane was characterized by atomic force microscopy (AFM), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, and contact angle measurements. The theoretical calculations of PVDF-HFP, Zn(4-PPOx)4Pc), and Zn(4-PPOx)4Pc/PVDF-HFP nanofibers were performed using a hybrid functional RB3LYP and the 6-31 G (d,p) basis set, employing Gaussian 09. DFT calculations illustrated that the calculated physical and electronic parameters ensured the feasibility of the interaction of PVDF-HFP with Zn(4-PPOx)4Pc via a halogen–hydrogen bond, resulting in a highly stable and remarkably reactive structure. Moreover, molecular electrostatic potential (MEP) maps were drawn to identify the reactive regions of the Zn(4-PPOx)4Pc and PVDF-HFP/Zn(4-PPOx)4Pc nanofibers. Molecular docking analysis revealed that Zn(4-PPOx)4Pc has highest binding affinity (−8.56 kcal/mol) with protein from S. aureus (1N67) mainly with ten amino acids (ASP405, LYS374, GLU446, ASN406, ALA441, TYR372, LYS371, TYR448, LYS374, and ALA442). These findings highlight the promising potential of Zn(4-PPOx) 4Pc/PVDF-HFP nanocomposite membranes in improving the efficiency of water desalination by reducing biofouling and providing antibacterial properties. [ABSTRACT FROM AUTHOR]

In today's technological landscape, advancing methods for producing conductive membranes that simplify and streamline the development of advanced interface materials is crucial. This study introduces a versatile and innovative method for fabricating superhydrophilic, conductive nanofibrous membranes based on the in situ synthesis of polypyrrole nanoparticles on poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) electrospun fibers. The composite membranes morphologically exhibit a particle‐decorated nanofibrous configuration, with polypyrrole nanoparticles distributed along the individual fibers' surface. The nanoparticle‐nanofiber configuration shows distinctive properties; electrochemically, the electrospun mats demonstrate excellent inherent electrical conductivity, good cyclic and high electrochemical stability, and low resistance. Furthermore, the amphiphilic and superhydrophilic behavior, achieved through nanotopography, porosity and interactions between the intrinsically conductive polymer and the PVDF‐HFP fibers, enables efficient uptake of polar and nonpolar analytes. The membranes also demonstrate good in vitro cell viability of both murine and human fibroblasts. Given its efficient interaction with liquids and omnidirectional 360‐degree conductivity, this material emerges as an excellent candidate for use as a biocompatible, multifunctional interface layer. The produced nanoparticle‐nanofibrous membrane materials offer a promising platform for interface applications, featuring enhanced spatiotemporal configurations and wide‐ranging applicability. [ABSTRACT FROM AUTHOR]

This study is the first application of a PVDF-HFP-based polymer inclusion membrane incorporating the poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and di(2-ethylhexyl)phosphoric acid (D2EHPA) as the base polymer and extractant for the extraction of bismuth(III), respectively. It is demonstrated that the PIM comprised of 60 wt% PVDF-HFP and 40 wt% D2EHPA is the most effective in the extraction of bismuth(III) from feed solution containing 20 mg L−1 bismuth(III) and 0.2 mol L−1 sulfate adjusted to pH 1.4. The extracted bismuth(III) ions are back-extracted quantitatively to the receiving solution containing 1 mol L−1 sulfuric acid. The stoichiometry experiments reveal that the Bi: D2EHPA ratio in the bismuth(III) extracted complex is 1:6, and D2EHPA is dimer. Moreover, it is shown that the studied PIM has high selectivity in the extraction of bismuth(III) over other interfering ions such as Mo(VI), Cr(III), Al(III), Fe(III), Ni(II), Zn(II), Cd(II), Co(II), Cu(II), and Mn(II). The interference of Fe(III) is also eliminated by masking with fluoride, leading finally to a nearly pure extraction of bismuth(III). [ABSTRACT FROM AUTHOR]

For enhanced security in hardware‐based security devices, it is essential to extract various independent characteristics from a single device to generate multiple keys based on specific values. Additionally, the secure destruction of authentication information is crucial for the integrity of the data. Doped amorphous indium gallium zinc oxide (a‐IGZO) thin‐film transistors (TFTs) using poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) induce a dipole doping effect through a phase‐transition process, creating physically unclonable function (PUF) devices for secure user information protection. The PUF security key, generated at VGS = 20 V in a 20 × 10 grid, demonstrates uniformity of 42% and inter‐Hamming distance (inter‐HD) of 49.79% in the β‐phase of PVDF‐HFP. However, in the γ‐phase, the uniformity drops to 22.5%, and inter‐HD decreases to 35.74%, indicating potential security key destruction during the phase transition. To enhance security, a multi‐factor authentication (MFA) system is integrated, utilizing five security keys extracted from various TFT parameters. The security keys from turn‐on voltage (VON), VGS = 20 V, VGS = 30 V, mobility, and threshold voltage (Vth) exhibit near‐ideal uniformities and inter‐HDs, with the highest values of 58% and 51.68%, respectively. The dual security system, combining phase transition and MFA, establishes a robust protection mechanism for privacy‐sensitive user information. [ABSTRACT FROM AUTHOR]

With the escalating issue of air pollution, the development of air filtration materials that can efficiently remove particulate pollutants, particularly nanosized particles, from air has attracted more and more research attention in recent years. Electrospun nanofiber membranes with a nanoscale pore structure have been widely used as air filtration materials. Along these lines, in this work, polyvinylidene fluoride-co-hexafluoropropyle (PVDF-HFP) nanofiber membranes with a multihierarchical gradient structure were fabricated by varying the sodium dodecyl sulfate (SDS) concentration. The proposed multihierarchical gradient structure was composed of upper, middle, and lower nanofiber layers, which could effectively filter PM0.3. The decreased nanofiber diameter by increasing the SDS concentration was attributed to the low surface tension and high charge balance. Compared with the single- and double-hierarchical PVDF-HFP nanofiber membranes, the triple-hierarchical PVDF-HFP nanofiber membranes demonstrated excellent air filtration performance. Among them, F014 yielded optimal air filtration performance, exhibiting a high filtration efficiency of 99.50%, a low pressure drop of 71.4 Pa, and a quality factor of 0.0878 Pa–1. Furthermore, the filtration efficiency was maintained above 99% and the pressure drop just increased by 27.4% over a 40 min air filtration test, which indicated that F014 showcased exceptional durability, owing to the multihierarchical gradient structure. Our work paves the way for the fabrication of electrospun nanofiber membranes with a multihierarchical gradient structure using a straightforward method, highlighting their potential as an alternative to traditional air filter materials for various practical applications. [ABSTRACT FROM AUTHOR]

In recent years, electronic devices with trendy flexibility and compatibility have become the competitive alternative to conventional electronics. In the present work, flexible polymer nanocomposite films composed of poly(vinylidene fluoride-co-hexafluoropropylene), iron oxide, and strontium titanate (PVDF-HFP/SrTiO3/Fe2O3) were synthesized by the solution-casting method. The formation and structural features of this composite material have been analyzed by X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Thermogravimetric (TGA), and SEM. SEM results confirm the homogeneous dispersion of SrTiO3 and Fe2O3 within the host polymer. The uniform dispersion of the embedded metal species enhances the dielectric values up to 462 on optimization with infused rigidity. The impedance studies of PVDF-HFP/SrTiO3/Fe2O3 were performed in the temperature region of 50–150 °C at various frequencies ranging from 50 Hz to 10 MHz and the AC conductivity studies suggested that synthesized polymer nanocomposite shows higher conductivity with the maximum conductivity value was 8.20 × 10−3S/m. Polymer nanocomposite films with large dielectric constant and minimum dielectric loss are highly recommendable for flexible energy storage applications. Also, rapid development of novel material for flexible electronics is in great demand, which suggests it is an alternate source for future energy storage application. [ABSTRACT FROM AUTHOR]

In the current study, novel Poly(vinylidene fluoride-co-hexafluoropropylene)/Cerium oxide/Silica carbide (PVDF-HFP/CeO2/SiC) flexible polymer nanocomposites were synthesized by solution casting technique. Structural changes involved in the composite formation between nano-fillers and host polymers were analyzed by X-Ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) techniques. SEM results confirm the homogeneous dispersion of nano-fillers (CeO2 & SiC) within the host polymer. Thermogravimetric analysis (TGA) was used to identify the thermal stability of the polymer nanocomposite with about 56% of residual residue for increased nano-fillers loading. Tauc plots confirm that the energy band gap of pristine host polymer decreased with the incorporation of nano-fillers. The dielectrics, impedance, and AC conductivity studies were investigated in temperature ranging from 50°C to 150°C and the frequency range between 50 Hz and 10 MHz measured by an impedance analyzer. As a function of nano-filler loading, the nanocomposites show a significant increase in the dielectric constant (ε′ = 272.92, 50 Hz, 50°C) with low dielectric loss (tan(δ) = 1.98, 50 Hz, 150°C) values. Impedance and the AC conductivity results suggested that addition of nano-filler decreases the impedance and improves the AC conductivity value from 1.67 × 10−4 S/m for pristine PVDF-HFP to 1.44×10−3S/m for 15% SiC. These results justify the material being efficiently applicable for flexible energy storage applications. [ABSTRACT FROM AUTHOR]

In this paper, a high‐performance composite nanofiber membrane with excellent air filtration and dye degradation properties was prepared by incorporating MIL‐53(Fe) nanoparticles into the electrospinning solution. The results showed that the filtration efficiency for PM2.5 of the PP/PVDF‐HFP/MIL‐53(Fe) composite nanofiber membrane reached up to 99.3% with the addition of 2 wt% MIL‐53(Fe). Moreover, the composite nanofiber membrane exhibited steady filtration efficiency across different parameters, including air velocity, PM2.5 concentration, and extended testing time. Furthermore, the incorporation of MIL‐53(Fe) significantly enhanced the removal efficiency of the composite nanofiber membrane toward Rh B, resulting in a remarkable 91% removal rate. The polymer/MOF composite nanofiber membranes prepared by simple and cheap electrospinning technology have a wide range of practical applications in the field of environmental protection. Highlights: PPM composite nanofiber membrane was prepared via electrospinning method.MIL‐53(Fe) nanoparticles were introduced to PPM composite nanofiber membrane.PPM composite nanofiber membrane showed excellent removal efficiency for PM2.5.PPM composite nanofiber showed a good removal performance for RhB in solution. [ABSTRACT FROM AUTHOR]

Polyvinylidene fluoride‐hexafluoropropylene (PVDF‐HFP) is a standard electrolyte membrane and binder material for lithium‐ion batteries (LIBs) because of the benefits of membrane formation and strong mechanical properties. Still, its use is limited due to unavoidable defects such as high crystallinity and poor electrochemical performance. In this paper, a larger specific surface area and three‐dimensional (3D) permeable lamellae carboxylated g‐C3N4 (HCN) were successfully prepared by HNO3 and introduced into the PVDF‐HFP to obtain a high‐performance composite separator. The wettability and electrolyte absorption of PVDF‐HFP separator can be improved through the carboxylated HCN. More crucially, because PVDF‐HFP has several active sites and low crystallinity, adding HCN can greatly increase the ionic conductivity of separators. The ionic conductivity of PH‐HCN at 25 °C is 0.52 S cm−1, 4.7 times higher than the initial PVDF‐HFP membrane, and the oxidation potential can reach 4.8 V. The assembled lithium‐ion batteries half‐cell has a capacity of 71 % at a 5 C rate and 94 % after 400 cycles at a 2 C rate. Therefore, the improved separator has the potential to be applied to high‐performance LIBs. [ABSTRACT FROM AUTHOR]

Supercapacitors based on ionic liquid gel polymer electrolytes (GPEs) have attracted considerable attention as a new energy storage device due to their good specific capacitance, good cycling capacity and stability. In this work, flexible gel polymer electrolyte (GPE) films were prepared and applied using three butyl imidazole ionic liquids with different anions as additives based on polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP). The structure and the mechanical properties of the GPE films and the electrical properties of the assembled symmetrical supercapacitors have been characterized. In particular, the structure–activity relationship between the structure and properties of the gel electrolyte was revealed by combining calculations with experiments. In particular, the structure–activity relationship between the structure and properties of the GPE was revealed through the combination of calculation and experiment. The results show that the electronegativity of the anions plays an important role in improving the stability and electrochemical properties of the gel system. This work is useful to further verify the influence of the anionic component of ionic liquids on the physical and chemical properties of gel electrolytes and to prepare more excellent solid electrolytes for supercapacitors. [ABSTRACT FROM AUTHOR]

Solid polymer electrolyte (SPE) films based on poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF–HFP) with salt and ionic‐liquid (IL) are synthesized using the solution‐cast technique and summarized in this review. Doping ILs or salts increases ionic conductivity up to the device level. This is further confirmed using differential scanning calorimetry (DSC) and X‐ray diffraction (XRD) measurements. Polarized optical microscopy (POM) affirms that enhancement in ionic conductivity is due to increase in amorphous nature of film. The complex nature of polymer electrolyte films is confirmed using Fourier transform infrared (FT‐IR) spectroscopy. Overall results show that doping IL into polyether matrix is advantageous material playing a dominant role in electrochemical devices. [ABSTRACT FROM AUTHOR]

In this work, poly(vinylidene fluoride‐hexafluoropropylene) (PVDF‐HFP)/mesoporous graphitic carbon nitride (mpg‐C3N4) composite fiber web have been prepared and characterized for photocatalytic methylene blue (MB) degradation and sensing applications. The electrospinning technique, operating at a flow rate of 1 mL/h and a voltage of 15 kV, was utilized to prepare the composite membranes of PVDF‐HFP with the uniform distribution of the mpg‐C3N4. The composite web demonstrated outstanding photocatalytic activity for the degradation of MB, reaching a quick 68% drop in MB concentration in just 45 min. The composite web furthermore worked as a sensor for MB detection. After MB exposure, the film resistance was increased, suggesting its potential as a chemiresistive sensor. The maximum resistivity of PVDF‐HFP/mpg‐C3N4 composites was found to be 90 Ω·m at 2% concentration of MB. The MB molecules' adsorption on the surface of the composite web and the existence of photocatalytic byproducts on the surface may be responsible for this shift in resistance. This dual functionality highlights the adaptability and potential of the PVDF‐HFP/mpg‐C3N4 composite web as a versatile material for environmental sensing and cleanup. This research presents a comprehensive approach to the synthesis, characterization, and evaluation of such flexible membranes for potential applications as self‐cleaning devices and chemiresistive sensor. Highlights: PVDF‐HFP/mpg‐C3N4 composite membranes act as an efficient material for MB degradation (68%) with visible light exposure.mpg‐C3N4 plays the role of active material in degradation.PVDF‐HFP/mpg‐C3N4 composite membrane also act as sensors for MB detection.Composite membrane becomes chemiresistive due to notable resistivity changes with MB concentration. [ABSTRACT FROM AUTHOR]

In this work, zirconia (ZrO2) nanoparticles (NPs) incorporated poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) nanocomposites were fabricated at varying weight ratios through solution casting approach. The structural properties of PVDF-HFP/ZrO2 nanocomposites have been investigated by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analysis. The strong interaction of ZrO2 with the PVDF-HFP matrix was observed revealing the structural modifications in the nanocomposites. The thermal degradation behavior of PVDF-HFP/ZrO2 nanocomposites was investigated by thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC) and differential thermal analysis (DTA). Addition of ZrO2 in the PVDF-HFP matrix has greatly improved the thermal stability of the PVDF-HFP/ZrO2 nanocomposites. The dielectric properties of the PVDF-HFP/ZrO2 nanocomposites were investigated as a function of frequency and temperature. The dielectric constant was observed to be higher at low frequency and decreased abruptly on increasing the frequency. Moreover, the impedance behavior of PVDF-HFP/ZrO2 nanocomposites with different loadings was studied by plotting Nyquist plots. These results revealed that PVDF-HFP/ZrO2 nanocomposites have shown enhanced thermal, dielectric and impedance properties as compared to neat PVDF-HFP film. These significant outcomes suggest that the PVDF-HFP/ZrO2 nanocomposites hold promise as viable options for energy storage applications. [ABSTRACT FROM AUTHOR]

Piezoelectric ceramic and polymeric separators have been proposed to effectively regulate Li deposition and suppress dendrite growth, but such separators still fail to satisfactorily support durable operation of lithium metal batteries owing to the fragile ceramic layer or low‐piezoelectricity polymer as employed. Herein, by combining PVDF‐HFP and ferroelectric BaTiO3, we develop a homogeneous, single‐layer composite separator with strong piezoelectric effects to inhibit dendrite growth while maintaining high mechanical strength. As squeezed by local protrusion, the polarized PVDF‐HFP/BaTiO3 composite separator generates a local voltage to suppress the local‐intensified electric field and further deconcentrate regional lithium‐ion flux to retard lithium deposition on the protrusion, hence enabling a smoother and more compact lithium deposition morphology than the unpoled composite separator and the pure PVDF‐HFP separator, especially at high rates. Remarkably, the homogeneous incorporation of BaTiO3 highly improves the piezoelectric performances of the separator with residual polarization of 0.086 μC cm−2 after polarization treatment, four times that of the pure PVDF‐HFP separator, and simultaneously increases the transference number of lithium‐ion from 0.45 to 0.57. Beneficial from the prominent piezoelectric mechanism, the polarized PVDF‐HFP/BaTiO3 composite separator enables stable cyclic performances of Li||LiFePO4 cells for 400 cycles at 2 C (1 C = 170 mA g−1) with a capacity retention above 99%, and for 600 cycles at 5 C with a capacity retention over 85%. [ABSTRACT FROM AUTHOR]

Abstract In today's technological landscape, advancing methods for producing conductive membranes that simplify and streamline the development of advanced interface materials is crucial. This study introduces a versatile and innovative method for fabricating superhydrophilic, conductive nanofibrous membranes based on the in situ synthesis of polypyrrole nanoparticles on poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) electrospun fibers. The composite membranes morphologically exhibit a particle‐decorated nanofibrous configuration, with polypyrrole nanoparticles distributed along the individual fibers' surface. The nanoparticle‐nanofiber configuration shows distinctive properties; electrochemically, the electrospun mats demonstrate excellent inherent electrical conductivity, good cyclic and high electrochemical stability, and low resistance. Furthermore, the amphiphilic and superhydrophilic behavior, achieved through nanotopography, porosity and interactions between the intrinsically conductive polymer and the PVDF‐HFP fibers, enables efficient uptake of polar and nonpolar analytes. The membranes also demonstrate good in vitro cell viability of both murine and human fibroblasts. Given its efficient interaction with liquids and omnidirectional 360‐degree conductivity, this material emerges as an excellent candidate for use as a biocompatible, multifunctional interface layer. The produced nanoparticle‐nanofibrous membrane materials offer a promising platform for interface applications, featuring enhanced spatiotemporal configurations and wide‐ranging applicability.

Exploration of blend polymer membrane with desire performances is a highly essential research topic because it makes them as key component of the battery technologies. However, the blend membrane cannot simultaneously meet out the high electrical insulation and ion conductivity. Here, we report porous PVdF-HFP based polymer membrane blended with P123 polymer which is prepared by phase inversion technique and along with solution casting technique for comparison. Especially, the major improvements can be claimed with porous PVdF-HFP blend with P123 matrix by phase inversion process that could be mainly due to increasing the disorganize crystallinity of the PVdF-HFP, thereby enhancing the ionic conductivity of PVdF-HFP/P123 than the same prepared by traditional solution casting. More importantly, our studies reveals that, besides having an effect of crystallinity and high ionic conduction PVdF-HFP/P123 blend matrix yield homogeneous pores with higher pore density when prepared by phase inversion approach. We attribute this to remarkable enhancement in higher electrolyte uptake and higher cation transport in the blend membrane. This facilitates high ionic conductivity of 7.06 × 10−5 S/cm and electrochemical stability of 2.8 V,while the solution casting approach display low ionic conductivity of 1.63 × 10−6 S/cm and electrochemical stability of 2.2 V, respectively. A symmetric supercapacitor device is fabricated with the membrane prepared by phase inversion process, resulting in a high specific capacitance of 80 F/g at the current density of 0.25 A/g with 90.51% specific capacitance retention at 0.5 A/g. The energy density of 90.9 W/kg can be achieved at the power density of 0.375 W/kg.

The present study investigates the influence of photosensitizer selection and the polymer electrolyte composition on the performance of quasi-solid-state dye-sensitized solar cells (QsDSSCs). Two benchmark ruthenium dyes, N719 and Z907, alongside a novel photoactive phenothiazine dye were used. Each dye was incorporated into a QsDSSC architecture employing poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) as the gel electrolyte matrix, with varying molecular weights, to investigate their impacts on the overall device performance and long-term stability. Our results demonstrated that the N719 dye exhibited the highest power conversion efficiency (PCE), attributed to its strong absorption in the visible spectrum and efficient electron injection into the TiO2 photoanode. Z907, on the other hand, showed moderate PCE due to its broader absorption profile but slower electron injection kinetics. The phenothiazine dye revealed promising PCE, with tunable absorption properties and efficient charge transfer. Furthermore, the impact of PVDF-HFP polymer gel electrolytes with varying molecular weights on cell stability was explored. The QsDSSC incorporating the PVH80 polymer with the phenothiazine dye exhibited reduced dye desorption, due to the effective dye molecules’ immobilization by the gel matrix, and consequently enhanced long-term stability over 600 h. This comparative study sheds light on the interplay between dye selection, the polymer gel’s properties, and QsDSSCs’ performance. These insights are crucial in designing robust and efficient QsDSSCs for practical applications.

In this study, flexible nanocomposites made from PVDF-HFP reinforced with carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) are manufactured using a sonication and solvent casting method for monitoring purposes. More specifically, the effect of the volume batch under the sonication process is explored. For CNT-based composites, the electrical conductivity decreases as the batch volume increases due to less effective dispersion of the CNTs during the 30-min sonication. The maximum electrical conductivity achieved in this type of sensor is 1.44 ± 0.17 S/m. For the GNP-based nanocomposites, the lower the batch volume is, the more breakage of nanoplatelets is induced by sonication, and the electrical response decreases. This is also validated by AC analysis, where the characteristic frequencies are extracted. Here, the maximum electrical conductivity measured is 8.66 ± 1.76 S/m. The electromechanical results also show dependency on the batch volume. In the CNT-based nanocomposites, the higher gauge factor achieved corresponds to the batch size, where the sonication may be more effective because it leads to a dispersed pathway formed by aggregates connected by tunneling mechanisms. In contrast, in the CNT-based nanocomposites, the GF depends on the lateral size of the GNPs. The biggest GF of all sensors is achieved with the PVDF-HFP/GNP sensors, having a value of 69.36 × 104 at 35% of strain, while the highest GF achieved with a PVDF-HFP/CNT sensor is 79.70 × 103 at 70%. In addition, cycling tests show robust electromechanical response with cycling for two different strain percentages for each type of nanocomposite. The sensor with the highest sensitivity is selected for monitoring two joint movements as proof of the applicability of the sensors manufactured.

Piezoelectric ceramic and composite materials are attractive for various applications, but they can be challenging to process. In this research, KNN-0.8ZnO with high density (ρ th =95 %), favorable microstructure, and suitable dielectric and piezoelectric properties (K=875, d 33 =125 pC/N, tanδ=0.01) was first synthesized. Additionally, polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) copolymer, known for its advantageous piezoelectric and mechanical properties, was selected as the polymer phase. subsequently, the KNN-0.8ZnO/xPVDF-HFP composite samples with a 0–3 connectivity pattern were made with the cold sintering method. The Taguchi design of experiment (DOE) was employed to determine the optimal condition for maximizing the figure of merit (FOM). Furthermore, an analysis of variance (ANOVA) was carried out to evaluate the significance of individual factors on each measured property. Phase identification was performed using X-ray diffraction (XRD) analysis, while the microstructure was examined using scanning electron microscopy. Among the different composite samples fabricated using the L9 orthogonal array (OA) of the Taguchi method, the KNN-0.8ZnO/20PVDF-HFP composite containing 20 wt% polymer phase, that was cold-sintered under a pressure of 400 MPa at 200 ͦC for 2 h, exhibited the highest FOM value of 1.945Pm2/N. This result aligns with the optimal conditions predeicated by the Taguchi DOE method. The compressive strength of the KNN-0.8ZnO/20PVDF-HFP composite was assessed through a compression test, yielding a value of 207 MPa, while the elastic modulus was approximately 3 GPa. The findings of this study demonstrate that the cold sintering method is an effective approach for producing dense piezoelectric composites with favorable electrical and mechanical properties, along with a high FOM for energy harvesting applications. • A new KNN-0.8ZnO/PVDF-HFP composite is made with cold sintering and the Taguchi design experiment was used to optimize the figure of merit. • KNN-0.8ZnO/20PVDF-HFP composite sample with 20 wt.% polymer, cold sintered with pressure of 400 MPa at 200 °C for 2 h, showed the best piezoelectric figure of merit. • The effective role of PVDF-HFP on dielectric, piezoelectric, and mechanical properties of KNN-ZnO/xPVDF-HFP composites cannot be ignored. • The cold sintering method is an efficient, simple and low-cost route to make dense 0-3 piezoelectric composites with favorable properties for energy harvesting applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • MOF was grown on the MoS 2 surface using the solution self-assembly technique. • The Nanoscale Confinement Polarization Pinning effect was proposed for the first time. • Provided theoretical support for the application of porous MOFs heterojunctions in the field of enhanced piezoelectricity. • The piezoelectric sensor has a sensitivity of 0.183 V a−1 and a stability of 3000 cycles. • The prepared piezoelectric sensor can be used in the field of health monitoring and exercise assistance. In this study, a novel theory called Nanoscale Confinement Polarization Pinning (NCPP) theory is proposed. This theory provides theoretical support for the application of heterojunctions composed of porous metal–organic frameworks (MOFs) and conductors or semiconductors in enhancing the piezoelectric effect of piezoelectric polymers. The heterojunction formed between the metal–organic framework UIO-66(Hf)–NO 2 and MoS 2 enables the porous MOF to firmly pin the MoS 2 onto the molecular chains of PVDF-HFP. During polarization, MoS 2 , being highly susceptible to the electric field, drives the movement of PVDF-HFP's molecular chains through UIO-66(Hf)–NO 2 , this results in the molecular chains of PVDF-HFP aligning along the electric field, leading to a more orderly arrangement of the electric domains within PVDF-HFP and enhancing the piezoelectric effect, with the d 33 value increasing from 8 pC N−1 to 27 pC N−1. The size of UIO-66(Hf)–NO 2 is approximately 50 nm, with a conduction band of −0.93 eV and a bandgap of 2.56 eV, while MoS 2 has a size of approximately 400 nm, a conduction band of −0.62 eV, and a bandgap of 1.27 eV. When MoS 2 and UIO-66(Hf)–NO 2 form a heterojunction, an interfacial electric field is generated at the junction, under the influence of this electric field, the PVDF-HFP molecular chains that penetrate into UIO-66(Hf)–NO 2 tend to align, increasing the crystallinity of the composite nanofibers from 29.9 % to 35.0 %. This study broadens the application of heterojunctions formed by porous metal–organic frameworks with other conductors or semiconductors to enhance piezoelectricity, providing theoretical support. [ABSTRACT FROM AUTHOR]

Wearable sensor technology has garnered increasing attention among researchers. In this study, the porous metal-organic framework containing nitroxide (UIO-66-NO 2) is pasted onto MXene by hydrogen bonding and then incorporated into PVDF-HFP for electrospinning to fabricate piezoelectric membranes. The porous structure of the metal-organic frameworks significantly contributes to the alignment of electric domain orientation within the piezoelectric membranes post-polarization, and the nitro of UIO-66-NO 2 helps to enhance the inductive power effect of the sensor, the piezoelectric constant of the composite piezoelectric membrane reaches 26.1 pC/N, 5.8 times that of the pure PVDF-HFP membrane (4.5 pC/N). The sensitivity reaches 20.99 V/N, which is 5.75 times that of the pure PVDF-HFP sensor (3.65 V/N). We conduct an exploration into the potential mechanisms behind the enhanced piezoelectric properties resulting from the incorporation of MXene and the metal-organic framework. The fabricated flexible pressure sensor exhibits commendable cyclic stability, boasting rapid response and recovery time (20/10.8 ms). The sensor demonstrates the capability to monitor human respiration and pulse, discern various parts of the human body and their respective amplitudes, differentiate between different materials, the pressure sensor has potential applications in human-computer interaction and health monitoring. [Display omitted] • UIO-66-NO 2 is self-assembled on monolayer MXene surface via hydrogen bonding. • The "nanoconfinement effect" of UIO-66-NO 2 and MXene would enhance piezoelectric effect. • The composite membrane has a piezoelectric constant (d 33) of 26.1 pC/N. • The sensor has high sensitivity (20.99 V/N) and fast recovery time (10.8 ms). • The sensor is able to monitor faint breathing and pulse. [ABSTRACT FROM AUTHOR]

All-solid-state lithium metal batteries (ASSLMBs) are renowned for their high energy density and safety, positioning them as leading candidates for next-generation energy storage solutions. In this study, pure polymer solid-state electrolytes are developed using the solution casting method, optimized for room temperature operation. The base material, poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), is enhanced with succinonitrile (SN) and polyacrylonitrile (PAN) to improve its electrochemical performance at room temperature. The optimized electrolyte, PSP-0.05, demonstrated superior characteristics, including an ionic conductivity (σ) of 3.2 × 10 -4  S cm -1 and a wide voltage window of up to 5 V. When integrated into full batteries, PSP-0.05 exhibited exceptional performance in multiplicative cycling tests at room temperature, achieving discharge specific capacities of 132 and 113 mAh g -1 at 3 and 5 C rates, respectively. Additionally, long-term cycling at 1 C rate resulted in an initial discharge-specific capacity of 145.2 mAh g -1 with over 94.9% capacity retention after 1000 cycles. Given the simplicity of the preparation process and its impressive electrochemical properties, the PSP-0.05 electrolyte holds significant potential for practical applications in safer ASSLMBs., (© 2024 Wiley‐VCH GmbH.)

[Display omitted] • PVDF-HFP addition is a key factor contributing to enhanced performance and stability of solar cells in space environments. • PVDF-HFP PSCs showed an improved PCE of 22.54% over pristine due to increased carrier lifetimes and reduced charge transport resistance. • PVDF-HFP addition enhances the crystallinity and stability of perovskite films in vacuum conditions. • PVDF −HFP PSCs demonstrated significantly better resilience compared to pristine PSCs under gamma-ray exposure. Metal halide perovskites have sparked considerable interest in photovoltaic (PV) research due to their exceptional optoelectronic attributes. The remarkable power conversion efficiency (PCE), superior power-to-weight ratios, adaptability to flexible substrates, and robust radiation tolerance position perovskite solar cells (PSCs) as a compelling option for futuristic space PV applications. In this study, we enhance the stability of PSCs by incorporating the additive poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) into the perovskite composition and evaluate their performance under vacuum and gamma-ray irradiation conditions. The fluorine content in PVDF-HFP establishes strong hydrogen bonding with the perovskite's organic cations and coordination bonds with Pb2+ ions, facilitating effective defect mitigation within the perovskite matrix. PVDF-HFP PSCs showed a marked increase in PCE of 22.54 %, comparing to 19.85 % for the pristine one. Furthermore, PVDF-HFP PSCs retained 70 % of their initial PCE after 600 h in a vacuum environment (2 × 10-7 torr). Additionally, it exhibited strong resilience to gamma-ray exposure. These results indicate that the integration of PVDF-HFP as an additive in perovskite solar cells significantly enhances their stability and performance in the harsh space condition. [ABSTRACT FROM AUTHOR]

As climatic conditions worsen and time passes, icing becomes an unavoidable issue. Drawing inspiration from the thermal regulatory properties inherent in polar bear fur, we introduce a biomimetic three-layer film. This film comprises a hydrophobic shield, a photothermal conversion layer, and an insulating layer through electrospinning. The multilayered micro/nanostructure within this film amplifies its light absorption capabilities, achieving an average absorption rate of 96.27 % across wavelengths ranging from 200 to 2500 nm. Thanks to the insulation layer's thoughtful design, the film boasts high photothermal conversion efficiency. When exposed to solar radiation for 360 s at an ambient temperature of 20 °C, its surface temperature swiftly climbs to 98.3 ± 1.1 °C. The film's anti-icing capabilities are evidenced by the fact that a droplet of water takes 2964.7 s to freeze on its surface, which is approximately 118 times that of aluminum. Additionally, it demonstrates excellent photothermal de-icing performance, swiftly eliminating thick layers of ice or frost under sunlight. Moreover, this film maintains its anti-icing and hydrophobic qualities even after multiple icing and de-icing cycles, as well as durability testing. It also possesses self-cleaning properties. Given its outstanding performance, this film has tremendous potential for long-term outdoor anti-icing applications. [Display omitted] • PDMS@MWCNTs/PVDF-HFP(P@MP) was designed, inspired by polar bear fur. • Three-layer film with superhydrophobic and photothermal properties was fabricated. • Photothermal conversion efficiency was improved by low heat loss insulation layer. • The freezing time of P@MP is 118 times than that of Al. • P@MP with excellent anti-icing/de-icing, self-cleaning, and durability properties. [ABSTRACT FROM AUTHOR]

Since triboelectric nanogenerators (TENG) are receiving attention as a promising technology in the domain of self-powered sensors for human activity monitoring and human machine interfaces, significant research is being conducted to enhance their performance and reliability. Herein, a novel V 2 CT X @poly(vinylidene-fluoride-co-hexafluoropropylene) composite nanofibrous (VPCN) mat was developed as a highly electronegative and stable tribolayer to improve the overall triboelectric performance. An abundant presence of functional groups (-F, -O, and -OH) on the V 2 CT X surfaces enhanced electronegativity, while formation of micro-capacitor networks into the polymer matrix enhanced the dielectric property along with the electron-trapping capacity, which reduced charge loss. The fabricated VPCN-TENG coupled with polyethylene oxide (PEO) nanofibrous mat exhibited a peak power-density of 18.2 W/m2, which was 3.5-fold higher than the pristine PVDF-HFP nanofibers-based TENG. The remarkable electrical output of the VPCN-TENG facilitated the transformation of biomechanical energy from various human motions into electrical power capable of powering commercial electronics such as stopwatches and thermo-hygrometers. Furthermore, the VPCN-TENG was successfully demonstrated as a self-powered pressure sensor with an extraordinary sensitivity of 25.17 VkPa-1 (1–42 kPa). In addition, the VPCN-TENG was used to fabricate a smart-belt as a self-powered motion sensor for monitoring various human activities such as walking, running, jumping, and posture monitoring during sitting and cycling. These findings offer valuable insights for designing high-performance TENG, fostering development of self-sustainable wearable electronics and advancements in self-powered sensors. [Display omitted] • V 2 CT X @PVDF-HFP composite nanofiber (VPCN) mat has been developed using facile electrospinning method. • Incorporation of ml-V 2 CT X into PVDF-HFP increases the dielectric constant with improved charge trapping capabilities. • VPCN mat coupled with PEO nanofiber, achieves high power density of 18.20 W/m2 and high sensitivity of 25.17 V/kPa. • VPCN-TENG exhibit outstanding stability over (>15 K) without deteriorating the materials pairs. • VPCN-TENG was demonstrated as a self-powered pressure sensor for real-time human activity and posture monitoring. [ABSTRACT FROM AUTHOR]

[Display omitted] • Developed polymer solid electrolyte membrane using solution casting method. • Achieved high ionic conductivity and strong mechanical properties in BPE membrane. • Demonstrated ultra-stable cycles and high-capacity retention in ASSLMBs. Polymer electrolytes have become widely popular on account of their low expenses, reduced weight, simple processing, and excellent safety features. However, polymer electrolytes have yet to find use in commercial batteries because of their limited mechanical durability and poor ionic conductivity. In this paper, an ultra-stable cycles and interfaces blending polymer electrolyte (BPE) suitable for all solid-state Li metal batteries was prepared by blending three polymers: polymethyl methacrylate (PMMA), polyvinylidene fluoride hexafluoropropylene (PVDF-HFP), and polyethylene oxide (PEO). Microstructure characterization showed numerous amorphous areas with strong interfacial strength of the BPE. The BPE3 exhibited a maximum of 15.65 MPa in tensile strength. BPE2 have excellent electrochemical performance, such as wide electrochemical windows (up to 4.7 V vs Li/Li+), high lithium ion transference numbers (up to 0.75), high ion conductivity (up to 1.87 × 10-4 S cm−1 at 60 °C), and excellent interface stability. By assembling all state-solid LiFePO 4 /BPE2/Li batteries for electrochemical testing, BPE2 exhibit high electrochemical characteristics. BPE2 discharge specific capacity is as high as 154.7 mAh g−1 at 1C. The BPE2 underwent 200 cycles at 0.5C and 400 cycles at 1C, with capacity retention rates of 95.7 % and 96.6 %, respectively. BPE is a promising electrolyte candidate for flexible lithium metal batteries. [ABSTRACT FROM AUTHOR]

In recent years, the electrodialysis (ED) technology has gained substantial attention for its role in recovering sulfuric acid from industrial wastewater. However, the typical anion exchange membranes (AEMs) have been known to exhibit notable proton leakage during ED, which can severely hinder the efficiency of acid concentration. To overcome this issue, we utilized a substrate made of poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP). This choice capitalizes on the presence of fluorine-containing groups for enhanced acid stability and tertiary amine groups to minimize water content, resulting in a significant improvement in proton-blocking capabilities of the AEMs. It is worth noting that, through a combination of partial cross-linking and quaternization, these AEMs not only maintain their acid concentration performance but also substantially reduce energy consumption. Additionally, we conducted a thorough analysis of the delicate balance between current efficiency and energy consumption in acid recovery systems. In contrast to conventional AEMs and commercially available proton-blocking membranes such as ACM, we highlight the exceptional acid concentration capability (C H + = 1.28 M) and the low energy consumption (3.3 kWh/kg) of AEM-1.2. This research breakthrough marks a significant advancement in the development of acid-blocking AEMs and strongly advocates for more efficient sulfuric acid recovery from industrial wastewater. [Display omitted] • A series of acid-blocking AEMs based on PVDF-HFP has been prepared. • The as-prepared AEM was partially quaternized to reduce energy consumption. • The final concentration of AEM prepared is better than that of commercial AEM. • The problem of poor acid enrichment performance of traditional AEMs was solved. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries (LIBs) have revolutionized the energy storage landscape and are the preferred power source for various applications, ranging from portable electronics to electric vehicles. The constant drive and growth in battery research and development aim to enhance their performance, energy density, and safety. Advanced lithium batteries (LIBs) are considered to be the most promising electrochemical storage devices, which can provide high specific energy, volumetric energy density, and power density. However, the trade-off between ionic conductivity and cycling stability is still a major contradiction for SPEs. In this work, a novel hydroxylated PAF-1 was designed and synthesized through post-modification, and the lithium-rich single-ion porous aromatic framework PAF-1-OLi was thereafter prepared by lithiation, achieved with a specific surface area to be 155 m 2 g -1 and a lithium content of 2.01 mmol g -1 . PAF-1-OLi, lithium bis(trifluoromethanesulfony)limine (LiTFSI), and poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) were compounded to obtain PAF-1-OLi/PVDF by solution casting, which had good mechanical, thermodynamic, and electrochemical properties. The ion conductivity of PAF-1-OLi/PVDF infiltrated with plasticizer was 2.93 × 10 -4 S cm -1 at 25 °C. The t Li + was 0.77, which was much higher than that of the traditional dual-ion polymer electrolytes. The electrochemical window of PAF-1-OLi/PVDF can reach 4.9 V. The Li//PAF-1-OLi/PVDF//LiFePO 4 battery initial discharge specific capacity was 147 mAh g -1 and reached 134.9 mAh g -1 after 600 cycles with a capacity retention rate of 91.2%, demonstrating its good cycling stability. The anionic part of lithium salt was fixed on the framework of PAF-1 to increase the Li + transfer number of PAF-1-OLi/PVDF. The lithium-rich PAF-1-OLi and the LiTFSI provided abundant Li + sources to transfer, while PAF-1-OLi helped to form a continuous Li + transport channel, effectively promoting the migration of Li + in the PAF-1-OLi/PVDF and effectively improving the Li + conductivity. This study afforded a novel polymer electrolyte based on lithium-rich PAF-1-OLi, which has excellent electrochemical performance, providing a new choice for the polymer electrolyte of lithium batteries.

Solid polymer electrolytes (SPEs) are regarded as a superior alternative to traditional liquid electrolytes of lithium-ion batteries (LIBs) due to their improved safety features. The practical implementation of SPEs faces challenges, such as low ionic conductivity at room temperature (RT) and inadequate interfacial contact, leading to high interfacial resistance across the electrode and electrolyte interfaces. In this study, we addressed these issues by designing a quasi-gel polymer electrolyte (QGPE), a blend of poly(vinylidene fluoride- co -hexafluoropropylene) (PVDF-HFP), poly(ethylene oxide) (PEO), and succinonitrile (SN), with the desired mechanical strength, ionic conductivity, and interfacial stability through a simple solution casting technique. The QGPE features a thin solvated PEO layer on its surface, which wets the electrode, reducing the interfacial resistance and ensuring a homogeneous Li-ion flux across the interface. The optimized QGPE exhibits a good lithium-ion conductivity of 1.14 × 10 -3 S cm -1 with a superior lithium-ion transference number of 0.7 at 25 °C. The Li/QGPE/Li symmetric cell exhibits a highly reversible lithium plating/stripping process for over 1300 h with minimal voltage polarization of ∼20 mV. The Li/QGPE/LiFePO 4 full cell demonstrates good rate capability and excellent long-term cycling performance at a 0.1 C rate at 25 °C, maintaining a specific discharge capacity of 148 mAh g -1 over 200 cycles. The effectiveness of QGPE for LIBs is proven using a graphite/QGPE/LiFePO 4 4 × 4 cm pouch cell, showcasing outstanding flexibility and tolerance against intentional abuse.

[Display omitted] • A detailed review of modified PVDF and its copolymer based proton exchange membrane for DMFC is explained. • The physical and electrochemical characteristics of PVDF and its copolymer-made membranes are discussed. • The advantages of these different polymers for making membranes are compared. • The future prospects for improvement in this polymer membrane are highlighted. Direct methanol is a promising portable electronic device that converts chemical energy into electrical energy by using easily available and environmentally friendly methanol fuel. Among its different components, the proton exchange membrane (PEM) is responsible for continuing the flow of hydration ions from anode to cathode, protecting from fuel crossover and keeping the electrons pushing towards the external circuit, which produces power. The Nafion-based proton exchange membrane is widely studied in direct methanol fuel cells because of its easy wettability, high ion exchange capacity, minimum methanol crossover, and mechanical strength due to its nono-porous structure. However, the methanol crossover increases in the Nafion membrane due to easy swelling when temperature raise due to reactions in the direct methanol fuel cells (DMFC) and dramatically reduces overall cell performance. Several types of polymers have been applied as PEMs for the replacement of costly Nafion membranes. Among these polymers, polyvinylidene fluoride (PVDF) and its copolymers such as polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) and poly (vinylidene fluoride-chlorotrifluoroethylene) (PVDF-CTFE) are considered effective for the production of high-class proton exchange membranes because of their less swollen nature, easy film forming ability, high mechanical strength, thermal stability and chemical inertness. Their easy modification with other hydrophilic polymers and nanoparticles as well as surface functionalization convert their hydrophobic nature that boosts proton conductivity. Moreover, the nano-porous structure with tortuous paths create with PVDF and copolymers efficiently reduces the methanol crossover. From high-crystalline PVDF to reduced-crystalline copolymers, effects on mechanical strength and water uptake of the proton exchange membrane. This review article presents the overall application of all PVDF family polymers and their modified forms as proton exchange membranes in direct methanol fuel cells. [ABSTRACT FROM AUTHOR]

Focusing on the uncontrolled discharge of organic dyes, a known threat to human health and aquatic ecosystems, this work employs a dual-functional catalyst approach, by immobilizing a synthesized bismuth sulfur iodide (BiSI) into a poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) polymeric matrix for multifunctional water remediation. The resulting BiSI@PVDF nanocomposite membrane (NCM), with 20 wt% filler content, maintains a highly porous structure without compromising morphology or thermal properties. Demonstrating efficiency in natural pH conditions, the NCM removes nearly all Rhodamine B (RhB) within 1 h, using a combined sonophotocatalytic process. Langmuir and pseudo-second-order models describe the remediation process, achieving a maximum removal capacity (Q max) of 72.2 mg/g. In addition, the combined sonophotocatalysis achieved a degradation rate ten and five times higher (0.026 min−1) than photocatalysis (0.002 min−1) and sonocatalysis (0.010 min−1). Furthermore, the NCM exhibits notable reusability over five cycles without efficiency losses and efficiencies always higher than 90%, highlighting its potential for real water matrices. The study underscores the suitability of BiSI@PVDF as a dual-functional catalyst for organic dye degradation, showcasing synergistic adsorption, photocatalysis, and sonocatalysis for water remediation. [Display omitted] • A BiSI@PVDF nanocomposite membrane was prepared and fully characterised. • A dual-functional catalyst approach was addressed, merging adsorption, sonocatalysis, and photocatalysis in a single method. • A Q max of 72.2 mg/g was achieved under US and VIS irradiation after 120 min. • The BiSI@PVDF exhibits notable reusability and performance in real water matrices. • The BiSI@PVDF is suitable for organic dye degradation, showcasing synergistic adsorption, photocatalysis, and sonocatalysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • PVDF-HFP was cross-linked by OV-POSS in the presence of ammonia water. • Cross-linking notably improved the dimensional stability of the PVDF-HFP membrane, without sacrificing its toughness. • GPE of cross-linked PVDF-HFP exhibited higher electrochemical stable window, σ and t +. • GPE of cross-linked PVDF-HFP displayed higher rate ability and better cycle performances. Separator of lithium-ion battery (LIB) faces safety challenges such as unsatisfied mechanical strength and insufficient dimensional stability especially at relatively high temperature. For that, a thermally stable nanoparticle of octavinyl polyhedral oligomeric silsesquioxane (OV-POSS) was mixed with poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) in solution in this work. It was found that the PVDF-HFP chains could be chemically linked with OV-POSS in the presence of ammonia water. The formed stable suspension of micelle was then cast to prepare a porous membrane. The dimensional stability, the mechanical properties and the microstructures of the obtained membranes were measured and analyzed, and compared with those of the membrane prepared by physically blending PVDF-HFP with OV-POSS. The results indicate that the chemically included OV-POSS nanoparticles can function as active filler to crosslink the PVDF-HFP chains, thus markedly reinforcing the membrane to improve its dimensional stability, but suppressing the crystallization of the polymer. The electrolyte up-taken membrane exhibits 0.76 mS∙cm−1 ionic conductivity, reveals 5 V electrochemical stable window and displays 0.75 lithium ion transference number, demonstrating an excellent gel polymer electrolyte (GPE). In addition, the GPE possesses higher rate ability and better cycle performances according to the battery tests. Therefore, our work provides a novel and easy strategy of cross-linking vinylidene fluoride polymer with reactive POSS to fabricate GPE with enhanced mechanical strengths, improved dimensional stability and better electrochemical properties, which suggests its promising potential in LIB. [ABSTRACT FROM AUTHOR]

Here we report the liquid-solid interaction in droplet-based triboelectric nanogenerators (TENG) for estimation of human Na + /K + levels. The exploitation of PVDF-HFP encapsulated WS 2 as active layer in the droplet-based TENG (DTENG) leads to the generation of electrical signal during the impact of water droplet. Comparison over the control devices indicates that surface quality and dielectric nature of the PVDF-HFP/WS 2 composite largely dictates the performance of the DTENG. The demonstration of excellent sensitivity of the DTENG towards water quality indicates its promising application towards water testing. In addition, the alteration in output signal with slightest variation in ionic concentration (Na + or K + ) in water has been witnessed and is interpreted with charge transfer and ion transfer processes during liquid-solid interaction. The study reveals that the ion mobility largely affects the ion adsorption process on the active layer of PVDF-HFP/WS 2 and thus generates distinct output profiles for diverse ions like Na + and K + . Following that, the DTENG characteristics have been exploited to artificial urine where the varying output signals have been recorded for variation in urinary Na + ion concentration. Therefore, the deployment of PVDF-HFP/WS 2 in DTENG holds promising application towards the analyse of ionic characteristics of body fluids., (© 2024 IOP Publishing Ltd.)

Natural polymer nanofiber-based separators with excellent thermal stability, mechanical strength, and electrolyte wettability have shown great potentials for advanced lithium ion batteries. However, there are two crucial issues to block their practical applications, including high moisture absorption and interfacial instability toward electrodes. Here, a surface coating strategy to overcome these disadvantages and promote natural polymer nanofiber-based separator performance is demonstrated. A hydrophobic polymer, poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), is adopted to coating on the surface of cyanoethyl-chitin nanofiber (CCN) separators. The as-fabricated CCN/PVDF-HFP composite separators not only exhibit much lower moisture absorption and higher interfacial instability but also retain high mechanical strength and ionic conductivity in comparison to CCN separators. The LiFePO 4 /Li cells using CCN/PVDF-HFP separators exhibit much better electrochemical cycle performance and enhanced capacity retention than that using CCN separators. A "surface coating" strategy is proposed to improve the performance of cyanoethyl-chitin nanofiber separators. The PVDF-HFP coating layer on the surface of cyanoethyl-chitin nanofiber separators can not only reduces the moisture absorption, but also improves the interfacial stability between separators and electrodes in lithium ion batteries. [Display omitted] [ABSTRACT FROM AUTHOR]