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We present the nanoengineering of Sb particles assisted by a conductive and stress-relieving network of carbon quantum dots (CQDs) and poly(3,4-ethylene dioxythiophene) poly(styrenesulfonate) (PEDOT:PSS), in the proper design of anode materials with high specific capacity and excellent stability for potassium-ion batteries (KIBs). The nanosized Sb particles are prepared by the CQDs as functional tuners in the morphology and surface, which tune the size to nanolevel and provide fast ionic channels and a soft matrix to relieve the volume changes. As the additional conductive and stress-relieving network layer, PEDOT:PSS offers enhanced electron/ion pathways and maintains the integrity of the Sb@CQD composite electrode. In the KIB, the prepared Sb anode exhibits battery performance with a high specific capacity of 480 mA h g

We created a cost-benefit analysis and swift point-of-care (PoC) testing for early stage Parkinson's disease (PD) that delivers the possibility of providing sensitive, rapid, and user-friendly analysis in home diagnostics applications. α-Synuclein (α-Syn) is considered a meaningful biomarker for the diagnosis of early stage PD. The PoC platform for diagnosis of PD is simply constructed with a conductive polymer and an aptamer receptor on a screen-printed electrode and exhibits a remarkable low detection limit of 1 × 10

Because of its high theoretical energy density, the Li–S battery (LSB) is regarded as one of the most promising next-generation energy-storage devices. However, LSBs undergo extreme electrochemical and physical changes in S during charge cycling, which limit battery performance. Here, we design a multifunctional polymer binder based on robust conductive webs comprising ring-opened poly­(vinylpyrrolidone) (PVP) connected with reduced graphene oxide (rGO). By forming an intermolecular structure in the simultaneous reduction of GO and ring-opening of PVP, the PVP–rGO web provides high affinity to Li polysulfides, mechanical robustness, and facile electron transfer, which can overcome the performance issues of LSBs. The prepared Li–S cell with the PVP–rGO web as binder presents the remarkable specific capacity of 374 mAh g–1 at 7 C and stable cycling performance with low capacity decay per cycle over 500 cycles at both 1 and 5 C.

Lithium–sulfur (Li-S) batteries are promising energy storage devices owing to their high energy density and the low cost of sulfur. However, they are still far from being applied commercially because of the detrimental capacity fade caused by the dissolution of lithium polysulfide (LPS) in liquid electrolyte. In this study, we introduced a new polymer binder having a redox-mediating function that assists in the reduction of soluble LPS to Li2S at the cathode to suppress the shuttle effect as well as enhance sulfur utilization. An amine group containing benzo(ghi)perylene imide (BPI) was synthesized and grafted onto poly(acrylic acid) to produce a redox-mediating polymer binder. An Li-S cell fabricated using the new redox-mediating polymer binder demonstrated a capacity decay retention of 0.036% per cycle up to 500 cycles at 0.5 C with a coulombic efficiency of 98%.

Coral-like structured barium titanate (BaTiO3) nanoparticles were synthesized as filler for a high dielectric elastomer. The nanoparticle size, and shape, and the reactivity of the synthesis were modified according to temperature, time, pH, and precursor materials. Dielectric properties of poly(dimethylsiloxane) (PDMS) composites were estimated by volume fractions of BaTiO3 of 5, 10, and 15 vol% for both sphere and coral-like shapes. As a result, coral-like BaTiO3–PDMS composites had the highest dielectric constant of 10.97, which was 64% higher than the spherical BaTiO3–PDMS composites for the 15 vol% fraction. Furthermore, the phase transition process and surface modification were applied to increase the dielectric properties through calcination and improved particle dispersion in the elastomer using polyvinylpyrrolidone (PVP). The dispersion of the PVP coated BaTiO3–PDMS composite was improved compared to pristine BaTiO3 as shown by SEM imaging. The coral-like BaTiO3 embedded composite could be used for electronic devices such as piezoelectric devices or electro-adhesive grippers, which require flexible and high dielectric materials.

Saponin, comprising hydrophilic glycoside moieties with a hydrophobic aglycone structure, is introduced for the first time as a multi-functional additive for high-performance sulfur cathodes. The hydroxyl groups efficiently suppress the lithium polysulfide shuttle effect and prepare sites that can strengthen the mechanical properties of the cathode through crosslinking with a polymer binder. The amphiphilic structure of saponin also helps to disperse active electrode materials in the sulfur cathode. Through the synergistic effects from its unique structure, the addition of a small amount (1 wt%) of saponin into the sulfur cathode boosts a 300% increase in the specific capacity of the cathode with a capacity decay of 0.012% per cycle at 2C over 1000 cycles.

A highly sensitive electrochemical impedance sensor for amyloid beta oligomer (AβO) was fabricated using a cellular prion protein (PrPC) bioreceptor linked with poly(thiophene-3-acetic acid) transducer. An additional thin layer of poly(3,4-ethylene dioxythiophene) embedded with gold nanoparticles was employed to provide high electrical conductivity and a large surface area. The sensing performace was investigated in terms of sensitivity and detection range. The fabricated sensor exhibited extremely low detection limit at a subfemtomolar level with a wide detection range from 10-8 to 104 nM and its utility was established in mice infected with Alzheimer's disease (AD). The developed AβO sensor could be utilized for early diagnosis of AD.

Electroadhesive devices can lift materials of different shapes and various types using the electrostatic force developed at the interface between the device and the object. More specifically, the electrical potential generated by the device induces opposite charges on the object to give electrostatic Maxwell force. Although this technology has a great deal of potential, the key design factors based on the fundamental principles of interfacial polarization have yet to be clearly identified. In this study, we identify that the lifting force is quantitatively related to the total length of the boundary edges of the electrodes, where the induced charges are selectively concentrated. We subsequently propose a model equation that can predict the electrostatic lifting forces for different object materials as a function of the applied voltage, impedance, and electrode-boundary length. The model is based on the fact that the amount of induced charges should be concentrated where the equipotential field distance is minimal. We report that the impedance magnitude is correlated with the electroadhesive lifting forces by analyzing the impedance characteristics of objects made of different materials (e.g., paper, glass, or metal), as attached in situ to the electroadhesive device.

We investigated the rheological and mechanical properties of a polypropylene (PP) composite reinforced by microfibrillated cellulose (MFC) fibers, of which the size was fractionated at ca. 24 µm by removing substances such as lignin or hemicellulose out of natural plants to exert the maximum mechanical performance of cellulose fibers. Due to the poor compatibility of MFC with a non-polar hydrophobic PP matrix, the MFC surface was modified through silylation and acetylation to increase its wetting and dispersion characteristics. The content of silylated-MFC could increase up to 30 wt% in the PP composite through large-volume process such as extrusion and injection molding. In addition, all mechanical properties of the silylated-MFC/PP composite were improved compared to untreated MFC/PP, acetylated MFC/PP composite. It was ensured by a strong shear thinning characteristic of the PP composite with silylated MFC content 30 wt% exhibiting a 69% lower viscosity (337 Pa·s at 4.7 s−1) than the neat PP at 180 °C. The same 30 wt% silylated specimens gave a well-dispersed fibrous MFC in PP, providing a tensile modulus (3.09 GPa) and a flexural modulus (3133 MPa), which were 64 and 81% higher than the neat PP, and 16 and 15% higher than the untreated-MFC composites, respectively. The flexural strength and the heat distortion temperature were also increased by 10 and 22%, compared to neat PP, respectively. In the acetylation reaction, the fibril structure of MFC was damaged due to full substitution by acetyl groups, and the reinforcing effect was insignificant as a filler in PP matrix. The developed silylated-MFC/PP composites provided excellent mechanical properties and high-loading processability that would be difficult to achieve by other eco-friendly composite systems.

Amyloid β oligomer (AβO) is a promising biomarker with potential to diagnose the Alzheimer’s disease (AD). To detect the low level of AβO is highly desirable for the early diagnosis of AD. Here we describe the fabrication and sensing performance of curcumin based AβO sensor. Curcumin-Ni was electropolymerized on Ni foam substrate, and the surface resistance change of the poly(curcumin-Ni) electrode depending on AβO concentration was confirmed by electrochemical impedance spectroscopy. The impedance response of the curcumin based sensor showed a proportional relationship with the concentrations of AβO in the range from 0.001 to 5 nM. The feasibility of the sensor was verified by the detection of AβO in artificial cerebrospinal fluid. The proposed AβO sensor presents valuable information related to early diagnosis of AD.

COVID-19 is a pandemic that has caused serious disruption in almost every day-to-day life around the world, and wearing a mask is essential for human safety from this virus. However, masks are non-recyclable materials, and the accumulation of masks used every day causes serious environmental issues. In this study, we investigate the recycling of mask materials for addressing the environmental problems and transforming as a high value-added material through chemical modification of masks. The recycled mask is applied as a separator for aqueous rechargeable batteries, and shows outstanding safety and electrochemical performance than the existing separator. This approach will lead to an advanced energy technology considering nature after overcoming COVID-19.

Next-generation energy storage devices such as lithium-sulfur batteries (LSBs) face several challenges including fast charging and high-power delivery. Thus, it is necessary to improve the stability of the electrodes with efficient electrochemical system. In this work, a durable sulfur cathode even at high rates is enabled via lean binder content. The binder consists of a chitosan cross-linked with a carboxylated nitrile-butadiene rubber (XNBR), which exhibits high affinity toward lithium polysulfide along with robust mechanical properties because of the synergistic effect of the polar chitosan and the elastomeric XNBR. Despite using extremely small content of binder (3 wt%), the LSB shows a highly stable long-term cycling performance with capacity retention decay values of 0.026% and 0.029% after 500 cycles at 5 and 10 C. Moreover, the cell shows an outstanding specific capacity of 228 mAh g-1 at an ultrahigh charge-discharge rate of 20 C. This approach may significantly improve the design of the sulfur cathode and pave a facile way to fabricate commercially viable next-generation energy storage devices.

Highlights A multi-functional interlayer for Li–S batteries has been developed to efficiently regulate the shuttle effect and enhance the sulfur utilization using hierarchical Fe3O4/C3N4 nanostructures. C3N4 nanotube exhibits high surface area and high affinity toward LPS, and the decorating Fe3O4 nanospheres on the surface of C3N4 nanotube accelerate the adsorption of LPS and improve the electronic pathways. The combination of Fe3O4 nanospheres and C3N4 nanotube leads to remarkable battery performance with 400% improvements in specific capacity compared with Li–S battery without using interlayer and a low capacity decay per cycle of 0.02% at 2 C over 1000 cycles. Electronic supplementary material The online version of this article (10.1007/s40820-020-00475-5) contains supplementary material, which is available to authorized users., Li–S batteries have attracted considerable interest as next-generation energy storage devices owing to high energy density and the natural abundance of sulfur. However, the practical applications of Li–S batteries are hampered by the shuttle effect of soluble lithium polysulfides (LPS), which results in low cycle stability. Herein, a functional interlayer has been developed to efficiently regulate the LPS and enhance the sulfur utilization using hierarchical nanostructure of C3N4 (t-C3N4) embedded with Fe3O4 nanospheres. t-C3N4 exhibits high surface area and strong anchoring of LPS, and the Fe3O4/t-C3N4 accelerates the anchoring of LPS and improves the electronic pathways. The combination of these materials leads to remarkable battery performance with 400% improvement in a specific capacity and a low capacity decay per cycle of 0.02% at 2 C over 1000 cycles, and stable cycling at 6.4 mg cm−2 for high-sulfur-loading cathode. Electronic supplementary material The online version of this article (10.1007/s40820-020-00475-5) contains supplementary material, which is available to authorized users.

Coral-like structured barium titanate (BaTiO

Zinc ion batteries (ZIBs) are promising candidates for application in next-generation energy storages because of their high capacity, low cost, and safety. However, structural issues such as irregular Zn growth, volume change, and electrochemical issues (side reactions and byproducts) hinder their practical application. Herein, we present an innovative method to develop a nanostructured conductive polymer shield for a Zn anode, which leads to an efficient and reversible ZIBs. The direct and spontaneous deposition of nanostructured conductive polymer on a Zn surface plays vital role of mechanical and electrochemical shield for Zn anode. The 3D-PPy@Zn anodes display high symmetric cycling stability for up to 1500 h at 1 mA cm−2, and the full cell assembled with a MnO2 cathode exhibits highly reversible battery performance.

Magnesium oxysulfate (MOS) whisker is considered as a promising inorganic material recently attracting a great attention for being used as a reinforcing filler for polymer composites due to high aspect ratio and extremely-low bulk density. In this study, the MOS was treated with 3-methacryloyloxypropyl-trimethoxy silane (MPS) via sol-gel condensation reactions, which successfully allowed melt mixing with polypropylene (PP) up to 30 wt% of MOS. The tensile strength at yield and modulus of the MOS/PP composites were substantially increased by 50.8% and 362%, respectively, when compared with the pristine PP. As a novel finding, the flame retardancy of MOS was proved by identifying water evolution at elevated temperatures giving out 9 wt% of water in 250–320 °C and 14 wt% in 350–420 °C in two steps. This work demonstrated that the MOS could be an excellent filler for PP not only increasing the mechanical properties in a great extent but also imposing flame retarding capability. Keywords: Magnesium oxysulfate, Surface modification, Mechanical properties, Flame retardant

Polymeric binder is extremely important for Si-based anode in lithium-ion batteries due to large volume variation during charging/discharging process. Here, natural rubber-incorporated chitosan networks were designed as a binder material to obtain both adhesion and elasticity. Chitosan could strongly anchor Si particles through hydrogen bonding, while the natural rubber could stretch reversibly during the volume variation of Si particles, resulting in high cyclic performance. The prepared electrode exhibited the specific capacities of 1350 mAh/g after 1600 cycles at the current density of 8 A/g and 2310 mAh/g after 500 cycles at the current density of 1 A/g. Furthermore, the cycle test with limiting lithiation capacity was conducted to study the optimal binder properties at varying degree of the volume expansion of silicon, and it was found that the elastic property of binder material was strongly required when the large volume expansion of Si occurred.

The effects of ZnO particle size on crosslinking and thermal aging behavior of natural rubber (NR) were investigated. NR vulcanizates filled with nano ZnO allowed higher crosslink density, lower polysulfide crosslink, and stronger mechanical properties than those filled with micro ZnO. After thermal aging, NR filled with nano ZnO exhibited much more stable chemical and mechanical properties. The high crosslink density as well as the formation of more stable mono- and di-sulfidic crosslinks was attributed to the good dispersion and high surface area of the nano ZnO.

Potassium-sulfur batteries have attracted significant research attention owing to the naturally abundant resources of potassium and sulfur, and have promising applications in large-scale energy storage systems. However, the sluggish reaction kinetics of K

Lithium-sulfur batteries (LSB) are highly promising candidates for next generation energy storage devices due to their high theoretical capacity and the low cost of sulfur. However, dissolution of lithium polysulfides (LPS) into electrolyte causes undesirable effects, resulting in loss of active materials, low Coulombic efficiency, and fast capacity fading. To address these issues, designed interlayers are inserted between a separator and S cathode to evaluate the effect of blocking of long chain LPS and catalytic conversion of LPS to Li2S2/Li2S on battery performance. In order to amplify the effect of interlayer, the Ni2P nanoparticles are electrochemically deposited on carbon fabric (CF) which exhibit excellent adsorption and conversion effect of LPS. A cell fabricated with the Ni2P@CF interlayer allows remarkable improvement in the capacity decay of 0.04% per cycle at 1C for 1000 cycles and outstanding high rate capability. The cell delivered a capacity retention of 64% employing a current density of 8 C.

With a diffusion-assisted post-crosslinking method, polymer microspheres containing epoxy groups are crosslinked with ethylenediamine (EDA), gradually diffusing and reacting in the particles via amine/epoxy ring-opening reactions as confirmed by FT-IR and DSC results. Using a microcompression test, we find that the mechanical property (deformability under different applied force, breaking points, and recoverability) of the crosslinked microspheres is varied when different amounts of EDA are used in the system, resulting from different crosslinking density of the particles. An additional feature of the EDA treatment is to generate amine groups on the surface of the microspheres, enabling us to produce hybrid microspheres. We exploit them as immobilization sites for gold nanoparticles, forming gold-coated crosslinked microspheres. We also introduce a sequential functionalization method to fabricate crosslinked microspheres with selective functional groups on the surface. This approach can be a facile method to produce functional microspheres with controlled mechanical and surface properties.

The practical applications of lithium–sulfur batteries (LSBs) are extremely limited owing to their poor electrochemical performance, which results from the shuttling effect of lithium polysulfides (LPSs) and the growth of Li dendrites. Here, we propose the use of the metal oxide, Ga2O3, which has several types of oxygen vacancies, as a multifunctional shield for ultrastable LSBs. The Ga2O3 shield enhances LPS adsorption by improving the catalytic ability; it also provides stable Li plating and stripping by suppressing Li dendrite growth. The multifunctional shielding of the LSB by the Ga2O3 interlayer results in outstanding ultrastable cycling performance, where the capacity decay was only 0.010% over 4,000 cycles at a high rate of 2C. The proposed multifunctional shield is expected to have a wide range of applications in energy storage systems in addition to LSBs.

We demonstrate a novel strategy for the preparation of copper sulfide dendrite. Copper dendrite was electrodeposited on nickel foam by hydrogen gas bubbling and then, the surface of the Cu dendrite was treated by a vapor-phase sulfurization from thiourea at 185 °C for 30 min. The dendritic structure exhibits large surface area and high ability for fast electron transport. CuS dendrites electrode provides excellent performance in terms of electrocatalytic activity, response rate, and stability to glucose sensor. The CuS dendrite demonstrates a high sensitivity of 8337 μA mM −1 cm −2 in the wide linear detection range 0.001–4.9 mM with a detection limit of 0.05 μM. The CuS dendrite electrode can be a potential competitive candidate for application to biosensors.

Here, we introduce a layered hollow sphere (LHS) architecture of iridium-decorated carbon electrode. The electrode was prepared by coating of a solution composed of graphene oxide (GO), IrCl3, and polystyrene bead followed by subsequent pyrolysis. The morphology of the electrode was investigated according to the composition of solution, and the electrocatalytic properties were characterized. The usage of GO highly enhanced the electrochemical surface area of the electrode (by ∼6 times). The LHS electrode also showed outstanding electrocatalytic properties: a current density of 89.99 mA/cm2 could be obtained at a potential of 1.6 V.

In the advent of the miniaturized mobile devices, the packaging technology is required utmost high performance of the thin composite laminates in such materials properties as the coefficient of thermal expansion (CTE) and stiffness. Accordingly, the composition of a thermosetting resin becomes extremely complicated often including multiple fillers, monomers and/or catalysts in thermoset-based glass fiber prepregs. The prepreg systems is so complicated that it is usually difficult to obtain a reliable kinetic description and methodology that could be used for the complex thermal cycles including both isothermal and dynamic-heating segments in a facile manner. In this investigation, we propose an isoconversional kinetic using an ultra-thin glass fiber epoxy prepreg with highly loaded silica filler (the ultra-thin glass fiber/silica bead epoxy prepreg) as a model system. The activation energy was determined as a function of the conversion of curing reactions, which was fitted to linear models. The kinetic prediction using the linear models showed an excellent agreement to isothermal experiments. The master curve of a conversion-dependent function which derived from activation energy dependency used to investigate the complex reactions of the ultra-thin glass fiber/silica bead epoxy prepreg.

Morphology-controlled synthesis of nickel sulfide (Ni3S2) was performed directly on Ni foam using thioacetamide as a sulfur ion source. Various morphologies of nickel sulfide were fabricated using a hydrothermal process by adjusting the solvent composition of ethanol and water. In the water-dominant condition, a dendrite structure was obtained; otherwise, a flaky structure was achieved. A hierarchical cauliflower-like structure was obtained at a solvent mixture composition of 1:1 and was used as non-enzymatic glucose sensor. The hierarchical Ni3S2 electrode showed a high level of electro-catalytic activity toward the oxidation of glucose (16,460μAmM(-1)cm(-2)) over a wide range of detection (0.0005-3mM) and a low detection limit (0.82μM) with excellent selectivity in the presence of several electroactive species.

The pristine lignin molecules contain multiple reactive hydroxyl [OH] groups, some of which undergo limited polymerization depending on their configuration (aromatic or aliphatic) or conformation. The key issue in lignin-polymerization is to quantify the number of hydroxyl groups in the pristine molecules for subsequent activation to specific lignin-polymer chain lengths or degree of grafting. In this study, using ε-caprolactone (CL) as a reactive solvent, we successfully polymerized CL on the [OH] sites in the kraft lignin macromonomers (LM, Mw = 1,520 g mol−1), which resulted in a thermoplastic lignin-polycaprolactone (PCL) grafted copolymer. We found that the average number of [OH] groups in the LM was 15.3 groups mol−1, and further detected 40–71% of the [OH] groups in the CL bulk polymerization. The degree of polymerization of PCL grown on each [OH] site ranged between 7 and 26 depending on the reaction conditions ([CL]/[OH] and reaction-time) corresponding to 4,780 and 32,600 g mol−1 of PCL chains per a LM. The thermoplastic characteristics of the synthesized lignin-PCL copolymers were established by the melt viscosity exhibiting a shear-thinning behavior, e.g., 921 Pa.s at 180 °C. The thermal stability was remarkable providing a Tid (2% of weight loss) of 230 °C of the copolymers, compared with 69 °C for the pristine lignin.

In this work, the ferrocene-encapsulated Zn zeolitic imidazole framework (ZIF-8) was prepared by the self-assembly of Zn ions and 2-methylimidazole and used for the dual detection of amyloid-beta oligomers (AβO), which is the main neuropathological hallmark of Alzheimer's disease. Ferrocene is an optically and electrochemically active signal which was successfully encapsulated inside of the ZIF-8 and released by the competitive coordination between Zn ions and AβO after being treated with AβO. The released ferrocene content was monitored by ultraviolet/visible spectrophotometry and cyclic voltammetry. The dual determination of AβO played a synergetic role in the quick qualitative and precise quantitative analyses in a wide detection range of 10-5 to 102 μM and good feasibility in artificial cerebrospinal fluid.

Li-S batteries (LSBs) are considered as next-generation energy-storage devices because of their high energy density. However, long-term use of LSBs is limited by the volume changes of sulfur and the shuttle effect. To address these issues, a multifunctional polymer binder is developed by combining a commercial binder and elastic rubber. Poly(vinyl pyrrolidone) (PVP) is used as the main binder, and carboxylated nitrile butadiene rubber (XNBR) is added to enhance its mechanical toughness and adsorb soluble lithium polysulfides. The XNBR is vulcanized with S to enhance its mechanical properties and chemical polarity. The combination of PVP and crosslinked-XNBR allows control of the volume change of sulfur, regulates soluble polysulfides, and ensures the good dispersion of the electrode material. LSBs with the proposed binder exhibit a remarkable battery-performance improvement of 300% after 500 cycles at 1C compared with an LSB using a PVP binder, as well as cycle stability, with a small capacity decay of 0.02% per cycle at 1C for 1000 cycles.

In this work, an ultra-sensitive amyloid beta oligomer (AβO) sensor is presented in the detection range at atomolar level. A hierarchical gold dendrite (AuD) was electrochemically prepared on a gold substrate. Poly(pyrrole-3-carboxylic acid) [PPy-3-COOH] was electrodeposited on AuD to maintain the outstanding electrochemical properties, such as high conductivity and large surface area. After immobilization of the cellular prion protein (PrPC) bioreceptor through amide bond formation, the electrochemical sensor was incubated in gradient concentrations of AβO. The impedance response of the dendritic PPy-3-COOH/PrPC biosensor showed a proportional relationship to the increase of AβO concentration from 10−9 to 10 nM. The sensitivity at an atomolar level and high selectivity to AβO can be used in the diseased mice and blood test for the early diagnosis of Alzheimer’s disease.