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In-situ incorporation of layered double hydroxides (LDH) nanocontainers into plasma electrolytic oxidation (PEO) coatings on AZ91 Mg alloy has been achieved in the present study. Fumarate was selected as Mg corrosion inhibitor for exchange and intercalation into the nanocontainers, which were subsequently incorporated into the coating. It was found that the thickness and compactness of the coatings were increased in the presence of LDH nanocontainers. The corrosion protection performance of the blank PEO, LDH containing PEO and inhibitor loaded coatings was evaluated by means of polarization test and electrochemical impedance spectroscopy (EIS). The degradation process and corrosion resistance of PEO coating were found to be greatly affected by the loaded inhibitor and nanocontainers by means of ion-exchange when corrosion occurs, leading to enhanced and stable corrosion resistance of the substrate.

The need to develop a low-power, low-cost nitrate, phosphate, and pH sensor and sensing system is essential for monitoring water quality in real-time. A novel interdigital sensor has been fabricated and characterized for temperature, nitrate, phosphate, and pH detection in water. The sensor is fabricated using the 3D printing technique where electrodes are formed using Multi-Walled Carbon Nanotubes (MWCNTs), and the substrate is developed using Polydimethylsiloxane (PDMS). The sensor is characterized by Electrochemical Impedance Spectroscopy (EIS) to determine various temperatures, pH levels, nitrate, and phosphate concentrations. Experimental outcomes prove that the developed sensor can distinguish nitrate and phosphate concentrations ranging from 0.1 ppm 30 ppm, pH values from 1.71 12.59, temperature from 0 45circ C. The sensitivity for temperature, nitrate, phosphate, and pH level of the sensor are 1.1974Ω/circ C, 1.9396Ω/ppm, 0.8839Ω/ppm and 1.0295Ω, respectively. A location-independent portable smart sensing system with LoRa connectivity is also developed to surveil water quality and get feedback from the experts. A machine learning algorithm trains the Arduino-based system and determines temperature, nitrate and phosphate concentrations, and pH level in real water samples. All the outcomes are compared with the standard method for validation. The sensor and the sensing system’s performances are highly stable, reliable, and repeatable to be a part of a smart sensing network for continuous water quality monitoring.

Electrolysis of seawater gets an attention to produce hydrogen for renewable energy technology. It significantly reduces the use of fresh water instead of seawater. Development of low temperature fabrication of electrocatalyst can explore seawater splitting by avoiding chloride reduction during the hydrogen production. In the present work, we fabricated low temperature hydrothermal growth of Cu2S electrocatalyst on Ni foam at constant temperature of 80 °C at different growth times of 1–3 h. The prepared Cu2S electrocatalyst grown for 1 h exhibited low overpotentials of 76 and 118 mV at 10 mA/cm2 (289 and 358 mV overpotentials at 100 mA/cm2) in 1 M KOH deionized water and seawater, respectively for hydrogen evolution reaction (HER). The Tafel plot of Cu2S catalyst grown for 1 h showed lesser Tafel slope value of 128 mVdec−1 than that of other growth times 2 h (136 mVdec−1) and 3 h (142 mV dec−1) indicating elevated electrocatalytic behaviour of Cu2S grown for 1 h. Electrochemical impedance spectroscopy (EIS) showed charge transfer resistance of 12.8Ω, 19.6 Ω and 25.7Ω, for Cu2S grown for 1, 2 and 3 h, respectively, this lower charge transfer resistance indicated higher charge transfer properties. The Cu2S electrocatalyst grown for 1 h sustained retention of 80% after 12 h continuous stability test. Therefore, the cost-effective and low temperature fabrication of Cu2S electrocatalyst proceeds for development of largescale seawater splitting for hydrogen production.

Abstrct Polycaprolactone/hydroxyapatite (PCL/HA) composite coating was fabricated by a combination of hydrothermal and dipping methods to delay the degradation of Mg alloy AZ31 as bioresorbable materials. The PCL/HA coating was composed of nano rod-shape HA crystals and PCL filled in the space of HA crystals. Compared with the single HA coating, the binding strength between the PCL/HA composite coating and Mg alloy was obviously improved and the PCL/HA coating still adhered to the surface of AZ31 substrate even after 38 days of immersion. The electrochemical corrosion rate of HA coated sample was reduced by ten times after being filled by PCL. The electrochemical impedance spectroscopy (EIS) and immersion test results showed that the PCL/HA composite coating could provide a more effective barrier for Mg substrate than the HA coating alone. The cytocompatibility and the antibacterial property of HA coating and PCL/HA coating were evaluated by culturing with bone marrow-derived mesenchymal stem cells (BMSCs) and methicillin-resistant staphylococcus aureus (MRSA) for 24 h under direct culture conditions, respectively. The PCL/HA composite coating showed better BMSC cell compatibility, more suitable for BMSC adhesion than HA coating alone and showed a potential application prospect as a biological materials. However, from the perspective of clinical applications, the antibacterial property of PCL/HA composite coating needs to be further improved.

Composite electrolytes containing lithium ion conducting polymer matrix and ceramic filler are promising solid-state electrolytes for all solid-state lithium ion batteries due to their wide electrochemical stability window, high lithium ion conductivity and low electrode/electrolyte interfacial resistance. In this study, we report on the polymer infiltration of porous thin films of aluminum-doped cubic garnet fabricated via a combination of nebulized spray pyrolysis and spin coating with subsequent post annealing at 1173 K. This method offers a simple and easy route for the fabrication of a three-dimensional porous garnet network with a thickness in the range of 50 to 100 µm, which could be used as the ceramic backbone providing a continuous pathway for lithium ion transport in composite electrolytes. The porous microstructure of the fabricated thin films is confirmed via scanning electron microscopy. Ionic conductivity of the pristine films is determined via electrochemical impedance spectroscopy. We show that annealing times have a significant impact on the ionic conductivity of the films. The subsequent polymer infiltration of the porous garnet films shows a maximum ionic conductivity of 5.3 × 10-7 S cm-1 at 298 K, which is six orders of magnitude higher than the pristine porous garnet film., Deutsche Forschungsgemeinschaft

In this article, a pioneering study is presented where the intermittent current interruption method is used to characterize the aging behavior of commercial lithium ion batteries. With a very resource-efficient implementation, this method can track the battery resistive and diffusive behaviors over the entire state of charge range and be able to determine the aging throughout the lifetime of the batteries. In addition, the incremental capacity analysis can be carried out with the same data set. This method can provide measurement results with a high repeatability and produce equivalent information as the electrochemical impedance spectroscopy method. In this study, both the resistive and diffusive parameters increase with the battery capacity fading. This method does not require advanced test equipment and even with a 0.1 Hz sampling frequency, it is possible to extract usable parameters by prolonging the interruption length. Therefore, it has the potential to be easily implemented in the charging sequence in electric vehicles or stationary storage batteries for aging diagnostics., IEEE Transactions on Transportation Electrification early access

The cerium conversion coating (CeCC) containing copper and manganese cations was applied to the galvanized steel. The microstructure and the composition of specimen were analyzed by field emission scanning electron microscopy (FE-SEM) and energy dispersive spectroscopy (EDS). Electrochemical impedance spectroscopy (EIS) and polarization tests were conducted in 3.5 wt% NaCl solution to investigate the coating corrosion resistance. The results show that there are improvements in corrosion resistance and microstructure of CeCC containing copper and manganese cations but copper ions increase corrosion resistance of CeCC from 5800 to 27000 Ω⋅cm2.

Kinetics and mechanism of the oxygen reduction reaction (ORR) in an alkaline medium have been studied on La2BO4±δ (B: Ni, Co or Mn) various mixed conducting oxides (MIEC: mixed electronic and ionic conductor). The preparation of these materials was carried out using the citrate method. The purity, the surface chemical state and the morphology were investigated by X-ray diffraction, X-ray photon-electron spectrometry (XPS) and scanning electron microscopy, respectively. An iodometric titration was also performed to evaluate the oxygen (over)-stoichiometry. The catalytic activity of the La2NiO4±δ (L2NO), La2CoO4±δ (L2CO) and La2MnO4±δ (L2MO) oxides towards ORR in alkaline medium was evaluated using the rotating disc electrode in 0.5 M NaOH solution completed by various electrochemical techniques such as cyclic voltammetry, linear voltammetry, the Koutecky–Levich diffusion model and impedance spectroscopy. The La2NiO4±δ sample is pure and more porous, but the La2CoO4±δ and La2MnO4±δ samples show secondary phases and are less porous. The XPS analysis shows that the surface of the La2NiO4±δ material is rich in hydroxide ions (OH−) and the Ni3+/Ni2+ ratio is very low unlike La2CoO4±δ and La2MnO4±δ materials in which OH¯ are low. Porosity and percentages of OH¯ and B3+/B2+ ratio are parameters influencing the ORR mechanism and therefore favouring, for this purpose, a one-step mechanism on La2NiO4+δ and a two-step mechanism on La2CoO4±δ and La2MnO4±δ electrocatalysts. Graphic abstract: [Figure not available: see fulltext.]

In practical pouch cell, LiNi0.5Mn0.3Co0.2O2/artificial graphite lithium ion battery using single-crystal LiNi0.5Mn0.3Co0.2O2 (S-NMC532) as cathode can have excellent cycle performance. However, single-crystal LiNi0.5Mn0.3Co0.2O2 inevitably suffers poor rate capability compared to the polycrystalline materials. Here, we systematically studied the relationship between microstructural characteristics and the practical rate performance, as well as explored the impedance change during the cycling process in the pouch cell. This work shows that the (001) plane microtexture of the electrode surface structure is a critical barrier for rate capability. Electron backscatter diffraction (EBSD), electrochemical impedance spectroscopy (EIS) and distribution of relaxation times (DRT) are conducted on the cathodes. These analyses allow to conclude on the influence of the (001) plane microtexture on the electrode surface, which illustrates a diffusion resistance of lithium ions, and then, leading a high interfacial resistance. Thus, this work confirms the main cause of the inferior rate capability of S-NMC532 and offers guidance for developing a battery with high rate and ultralong cycling life.

Ionic liquids (ILs) are promising electrolytes and many efforts have been made in basic scientific research as well as in applied research. In this contribution, we synthesised a variety of partly novel phosphonium ILs with different anions as well as with different compositions and lengths of the side chains of the cations. We measured a variety of their important transport properties such as viscosity, conductivity and diffusivity by means of stress-controlled rheology, impedance spectroscopy and PFGSTE NMR diffusometry. The results are analysed with respect to different models for derivation from ideal behaviours such as the ionicity and the (fractional) Walden rule depending on their molecular structure. These models are well established in the literature and are herein applied to rarely investigated but promising phosphonium ILs, with a particular emphasis placed on the effect of ether side chains. In comparison, the models show a qualitative correlation but distinct deviation in the quantification especially in the temperature dependent values and with other IL systems. These results aim to facilitate a better understanding of the IL properties depending on the molecular composition and by this way help to choose the ILs with optimal properties for practical applications.

Tris(trimethylsilyl)borate (TMSB) has been intensively studied to improve the performances of lithium-ion batteries. However, it is still an interesting issue needed to be resolved for the research on the Li+ solvation structure affected by TMSB additive. Herein, the electrochemical tests, quantum chemistry calculations, potential-resolved in-situ electrochemical impedance spectroscopy measurements and surface analyses were used to explore the effects of Li+ solvation structure with TMSB additive on the formation of the cathode electrolyte interface (CEI) film in LiNi0.8Co0.1Mn0.1O2/Li half cells. The results reveal that the TMSB additive is easy to complex with Li+ ion, thus weaken the intermolecular force between Li+ ions and ethylene carbonate solvent, which is benefit for the cycle performance. Besides, the changed Li+ solvation structure results in a thin and dense CEI film containing compounds with Si–O and B–O bonds which is favorable to the transfer of Li+ ions. As a result, the performances of the LNCM811/Li half cells are effectively improved. This research provides a new idea to construct a high-performance CEI film by adjusting the Li+ solvation structures.

To enhance the corrosion resistance of an aluminum (Al) 6082 alloy, our research used electroless deposition to coat a trio sequence of Zn-Cu-Sn layers: zinc, copper and tin. To isolate the reactions and micro-mechanisms in the tin coating, the Zn-Cu layering parameters of time, temperature, and bath concentration were held constant while varying those during the Sn electroless deposition. Microstructures and layer thicknesses of the coated samples were studied using both optical and scanning electron microscopy (SEM). Local chemical compositions were analyzed using energy dispersive spectroscopy (EDS). Tin deposition on the Cu layer starts with a displacement reaction formed by the nucleation of discontinuous bulges that gradually grow into inhomogeneous crowns. During Sn deposition, surface Cu consumption and bath composition varies hindering access to displacement reactants, thus curtailing the significance of displacement. However, deposition continues via reduction and disproportionation directly tied to the solution. Peak layer quality was deposited at a temperature of 45 oC with a 1.5 times concentration for 1200 sec. Anti-corrosion behavior of the Sn-coated sample was examined by Electrochemical Impedance Spectroscopy (EIS) to detect notable enhancement.

A combinatorial library of twenty-three, phase pure, near-NMC111 (LiNi0·33Mn0·33Co0·33O2) compositions were synthesised and their electrochemical performance, was mapped (in lithium ion half-cells). Each of the 23 compositions was made in series, using a two-step process of 1) a rapid initial continuous hydrothermal precipitation, followed by 2) solid state lithiation. The 23 lithiated NMC samples were then subjected to analytical methods including electron microscopy (selected samples), Powder X-ray Diffraction and electrochemical tests in half cell Li-ion configurations versus Li metal. A sample with a Ni:Mn:Co (NMC) ratio of 39:28:33, revealed a specific capacity of 150 mA h g−1 at a C/20 rate, which was 63 and 43% greater capacity than NMC111 and NMC433 samples produced in this work, respectively. The sample with NMC ratio 47:25:28, showed the best capacity retention characteristics, retaining 70% of its C/20 capacity at 1C, after 40 cycles. Further analysis of all the samples by cyclic voltammetry and electrochemical impedance spectroscopy, allowed compositional mapping of diffusion coefficients. Overall, the mapping data revealed a gradual change of properties across compositional space, which has validated our combinatorial approach and allowed identification of the optimum performing near-NMC111 cathode materials.

Selective and efficient electrochemical analytical methods for the characterization of the corrosion behavior of beryllium bronze alloys are significant and necessary. These electrochemical methods are based on open-circuit chronopotentiometry curves, potentiodynamic polarization, and electrochemical impedance spectroscopy. From the electrochemical analysis, the results show that the corrosion reaction of the untreated samples became more severe as the NaCl concentration was increased. However, the corrosion reaction was not obvious when the alloy was treated by commercial latex paint and laboratory-produced latex paint. Furthermore, the corrosion potential has same variation tendencies and the value of the corrosion potential was more positive when the alloy surface was treated by the laboratory-produced latex paint. The maximum and minimum of the corrosion potential were found for conditions using the untreated samples and samples treated with the laboratory-produced latex paint. The corrosion c...

In this study, a new self-healing strategy that can simultaneously recover the corrosion resistance and the adhesion strength of coatings was introduced. The coating was based on a shape memory epoxy resin containing ethylene vinyl acetate (EVA) microspheres loaded with Ce(NO3)3 inhibitors, and was cured at a relatively high temperature to facilitate the fusion of adjacent microspheres for a strengthened self-healing effect. The electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscopy (SECM) results demonstrated that the shape memory effect of epoxy matrix, the filling of molten EVA microspheres as well as the release of Ce(NO3)3 inhibitors contributed synergistically to suppress the corrosion reaction at the coating damage. After healing, the low frequency impedance modulus of the coatings containing Ce(NO3)3-EVA microspheres was three orders of magnitude higher than that of the blank epoxy coating. The adhesion strength of the coatings containing Ce(NO3)3-EVA microspheres on the metal substrate was also largely repaired thanks to the strong bonding effect of the EVA microspheres.

Applications of superhydrophobic (SHS) and lubricant infused surfaces (LIS) involve exposure to corrosive environments from the acidic to the basic, at a range of temperatures, that are not fully characterized. We present for the first time a multifactorial study of the effects of surface fabrication method, surface modification, surface functionalization time, temperature and pH of the immersion medium on the corrosion performance of nonwetting copper surfaces. Bioinspired SHS and LIS fabricated using facile methods of etching and electrodeposition are systematically assessed using potentiodynamic polarization measurements for their corrosion resistance in saline solution ( pH ≈ 7) over a temperature range 23–85 °C. SHS and LIS are shown to exhibit diminished corrosion rate, by up to two orders of magnitude, compared to bare copper surface. An Arrhenius model is developed for the first time, describing the temperature-dependent corrosion rate of SHS and LIS. Electrochemical impedance spectroscopy is used to show that corrosion resistance of LIS is larger by three orders of magnitude in extremely acidic ( pH = 1) and by an order magnitude in extremely alkaline ( pH = 14) media compared to bare copper surface. Etched LIS are generally more resistant to corrosion compared to SHS at all temperatures with excellent microstructural durability.

In this work, we report the structure-dependent electrochemical performance of cobalt carbonate hydroxide (Co2(OH)2CO3) nanocrystals by experimental investigation and theoretical simulation. Different Co2(OH)2CO3 nanostructures including two-dimensional (2D) nanosheets (NSs) and one-dimensional (1D) nanowires (NWs), were synthesized on self-supported carbon cloth substrates by a facile hydrothermal method. Compared to 1D NWs, 2D Co2(OH)2CO3 NSs provided a short ion transfer path, and low electron transfer resistance during the electrochemical reaction. At the current density of 2 mA cm−2, 2D Co2(OH)2CO3 NSs exhibited a higher area capacitance of 2.15F cm−2 and better cycling performance (96.2% retention after 10,000 cycles) than that of 1D NWs (1.15F cm−2 and 90.1% retention). First-principles density functional theory (DFT) calculations revealed that the band gap of the (1 2 0) facet in 2D NSs was 0.2 eV, far less than of the (2 0 0) facet in 1D NWs (1.04 eV). Electrochemical impedance spectroscopy (EIS) measurements further indicated that the electron transfer and reaction kinetics were more efficient in 2D NSs. This work can provide an important insight in understanding the mechanism of electrochemical energy storage.

Ba3MoNb1-xGaxO8.5-δ (BMNG, 0 ≤ x ≤ 0.2) powders are successfully prepared by sol-gel autoignition method. The effects of acceptor-type Ga3+ doping on Ba3MoNbO8.5 (BMN) are characterized by thermogravimetric analysis, X-ray diffraction, scanning electron microscope, Raman spectroscopy, and electrochemical impedance spectroscopy. All BMNG samples crystallize as a single phase in the R-3m space group and show great phase stability at various environments. Doping a small amount of gallium can effectively improve bulk conductivity and sintering density of BMN. The ionic conductivity of Ba3MoNb0.9Ga0.1O8.5-δ (BMNG10) is the highest, which can reach 2.05 × 10−2 S cm−1 at 800 °C. The enhanced ionic conductivity is primarily related to the increase of oxygen vacancy concentration and the number of tetrahedral units within the structure. In addition, through successfully assembling and evaluating a single cell supported by the BMNG10 electrolyte, it is proved that the practical utilization of BMNG10 in intermediate temperature-solid oxide fuel cells (IT-SOFCs) is feasible. In short, hexagonal perovskite derivative BMNG10 is a promising oxide ion conductor for IT-SOFCs.

Novel epoxy resin (E)/CNW nanocomposite coatings were developed with different total contents of rare-earth doped aluminate nanoparticles (REA NPs). The produced epoxy-cellulose nanowhiskers-rare earth doped aluminate nanoparticles (E-CNW-REA) coatings were applied onto mild steel. The epoxy/CNW nanocomposite coatings were characterized by X-ray fluorescence analysis (XRF), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDXA), transmission electron microscope (TEM) and infrared spectra (FT-IR). Both colorimetric properties and transparency of the nanocomposite coatings were proved by exploring UV–Vis absorption spectroscopy and CIE Lab parameters. The hardness and superhydrophobic properties were also explored. The photoluminescent transparent coatings showed an excitation at 365 nm, and a bright green emission wavelength at 517 nm under UV light. The corrosion protection performance of the coated mild steel samples soaked in an aqueous solution of sodium chloride (3.5%) was investigated using electrochemical impedance spectroscopy (EIS). The coatings with CNW were found to have anti-corrosion properties. Moreover, the nanocomposite coating with CNW (1 w%) was monitored to exhibit the most pronounced long-persistent photoluminescence for 60 min in the dark. The photoluminescent coatings exhibited highly durable long-lasting phosphorescence. Thus, the current strategy can be considered as a simple promising technology for industrial production of anti-corrosive, superhydrophobic and long-persistent phosphorescent.

Graphene oxide (GO) can enhance the corrosion resistance of epoxy coating, but there are problems such as poor filler dispersion and mechanical damage that will reduce the coating corrosion resistance. To resolve these problems, here, we used a facile and green liquid-phase synthetic strategy to grow covalent organic framework (COF) on GO sheets with 1,3,5-Triformylphloroglucinol and p-phenylenediamine as monomers for the COF synthesis. The COF could not only improve the compatibility of GO with epoxy coating, but also act as a nanocontainer for loading corrosion inhibitors. Electrochemical impedance spectroscopy showed that the low-frequency impedance of GO/COF-2% coating immersed in 3.5 wt% NaCl solution for 60 days was 8.58 × 108 Ω cm2. This was one order of magnitude higher than that of GO-2%, showing excellent corrosion resistance. Then, corrosion inhibitor of benzotriazole (BTA) was loaded into GO/COF, where the adsorption and release of BTA was controlled by environmental pH values. Results proved that the GO/COF@BTA-2% reinforced epoxy coating had superior corrosion resistance as well as self-healing ability because of the good compatibility, greater crosslinking density and controllable release of BTA.

Studies on the formation and evolution of the solid electrolyte interface (SEI) film under different ambient temperatures are important to understand the failure behavior of lithium-ion batteries (LIBs). Herein, in-situ electrochemical impedance spectroscopy (EIS) test is performed on the whole discharge process of Si@Graphite@C/Li cell at 0, 25 and 55 ℃, respectively. Combining with scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy characterizations, it is found that the SEI film undergoes a complicated evolution process of pre-formation, self-improvement and gradual decay in succession at 25 ℃. Besides, due to the dissolution of organo-alkyl lithium at high temperature, the formed film is mainly composed of LiF, Li2CO3 and other inorganic salts, which helps to decrease the impedance. However, the electrolyte is consumed continuously on the new exposed interface, leading to the degraded performance of the cell. Moreover, the dynamic properties of Li+ ions are poor at low temperature, though the migration ability of Li+ ions in the solid phase can be improved as the cycle goes on. Therefore, the development and application of in-situ EIS technology are expected to become an important means to explain the electrochemical performance of batteries.

In the current investigation, a triazole, namely 1-Amino-2-mercapto-5-(4-(pyrrol-1-yl)phenyl)-1,3,4-triazole (AMPPT), was synthesized and characterized using ¹H and ¹³C nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopies in addition to CHN micro elemental analysis. A preliminary study of the title compound as corrosion inhibitor for mild steel in 1 M hydrochloric acid solution was evaluated by performing gravimetrical, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements in addition to scanning electronic microscope (SEM). The obtained experimental results indicated that AMPPT works perfectly as a corrosion inhibitor for mild steel in 1 M HCl solution and its effectiveness is up to 96.3% at 500 ppm and corrosion inhibition efficiency increase with increasing the concentration of tested inhibitor, suggests that the adsorption of AMPPT molecules on the mild steel surface obeyed the Langmuir adsorption model. Polarization measurements show that the studied inhibitor is a mixed type. EIS measurements revealed that the charge transfer resistance increases with increasing concentration of AMPPT. The free energy (ΔGoads) value showed that the adsorption of AMPPT molecules suggesting a mixed-mode of physisorption and chemisorption. Density functional theory (DFT) calculations were performed on AMPPT molecules to determine the quantum parameters and the relationship between the inhibitor structure and inhibiting efficiency. The molecular parameters, such as energy gap and frontier molecular orbitals (HOMO and LUMO), the absolute electronegativity (χ) value, and the fraction transfer of electrons (∆N) were also calculated and correlated with inhibition activity. The theoretical outcomes showed that the inhibition efficiency of AMPPT increased with the increase the energy of HOMO, and the nitrogen and sulphur atoms are the most likely sites for bonding by giving electrons to the unoccupied 3d-orbitals of Fe atoms on the mild steel surface.

Although the power conversion efficiency (PCE) of perovskite solar cells (PSCs) has improved greatly in recent years, the challenges of efficiency and stability still need to be overcome before these solar cells can be used in commercial applications. Here, a weak acid buffer, hydroxyethyl piperazine ethane sulfonic acid (HEPES), is used to passivate the interface of an SnO2 electron transport layer (ETL) and a photoactive layer in n-i-p solar cells. The device efficiency based on a SnO2/HEPES ETL reaches 20.22%, which is 9.7% higher than that of the control (18.43%), and the device stability is also significantly improved. The improvement in the device performance is mainly due to the introduction of the HEPES interface layer to adjust the interface energy level, which also improves the crystallinity of the perovskite film and reduces the interface defects. Electrochemical impedance spectroscopy and transient photovoltage/photocurrent results show that the HEPES-modified PSCs have lower charge transfer resistance, weaker leakage current intensity and improved interfacial charge separation and transport.

Indirectly monitoring Listeria monocytogenes (LMs) via gas sensor detecting metabolites 3-hydroxy-2-butanone (3H-2B) biomarker is a newly-emerged strategy. However, such sensors are required to simultaneously endow with outstanding selectivity, high sensitivity and ppb-level detection limit, which remains technologically challenging. Herein, we have developed highly selective and sensitive 3H-2B sensors with zinc oxide nanorods decorated with cobaltosic oxide nanoparticles (ZnO NRs / Co3O4 NPs), which have been synthesized by an optimized hydrothermal and annealing process. Specifically, the ZnO NRs / Co3O4 NPs exhibit ultrahigh sensitivity toward 5 ppm 3H-2B (Ra / Rg = 550 at 260 oC). Meanwhile, the sensor prototypes enable to detect as low as 10 ppb 3H-2B, show excellent long-term stability, and present remarkable selectivity through interfering selectivity survey and principal component analysis (PCA). Such outstanding sensing performance is attributed to the the modulated electron depletion layer by n / p heterojunction and abundant gas diffusion pathways of radial architectures, which is testified via electrochemical impedance spectroscopy test, Mott-Schottky measurement and ultraviolet-visible absorption analysis. Our highly selective and sensitive ZnO NRs / Co3O4 NPs are potential in real-time detection of 3H-2B biomarker of LMs.

This work reports urea as a promising complexing agent in sodium carbonate-based alumina slurry for chemical?mechanical planarization (CMP) of tantalum and copper. Ta and Cu were polished using Na2CO3 (1 wt. %) with alumina (2 wt. %) in the presence and absence of urea. The effect of slurry pH, urea concentration, applied downward pressure and platen rotational speed were deliberated and the outcomes conveyed. Prior to the addition of urea, the Ta removal rate (RR) was observed to increase with pH from acidic to alkaline, having a maximum RR at pH 11. However, Cu RR decreases with increasing pH with minimum RR at pH 11. With the addition of urea in the slurry, a Cu to Ta removal rate selectivity of nearly 1:1 was encountered at pH 11. The addition of urea simultaneous boosts the Ta RR and suppresses Cu RR at pH 11, as it adsorbs on the metal surface. Potentiodynamic polarization was conducted to determine the corrosion current (Icorr) and the corrosion potential (Ecorr). Electrochemical impedance spectroscopy of both metals was carried out in the proposed formulation and the obtained outcomes are elaborated.

Mixed phase of iron telluride based thin films consisting of nanopebbles has been grown successfully over conducting stainless steel (SS) substrate through successive ionic layer adsorption reaction (SILAR) process. Crystal structural and elemental states through XPS revealed clear indication of FeTe: Fe2TeO5 mixed phase growth and well supported through FTIR studies. Agglomeration of embedded quantum dots forming nanopebbles like surface architecture resulting in enhanced hydrophilic nature evident through contact angle and higher surface roughness by atomic force micrographs found beneficial as more electroactive surface area for electrolyte ions to interact. This helped to achieve a significant specific capacitance of 591 F/g (166 mF/cm2) @3 mV/s potential scan rate and, 107 F/g (30 mF/cm2) @0.4 mA/cm2 in NaCl electrolyte. Performed electrochemical impedance spectroscopy (EIS) studies explored clear insight of the solution and charge transfer resistances, and relaxation time constant. Iron telluride based thin film clearly demonstrates very high value of pseudo capacitive contribution than the electric double layer due to the intrinsic pseudocapacitive behavior of mixed phase.

This paper report a new biodegradable epidermis of onion (Allium cepa) doped with low viscosity ionic liquid as novel electrolyte for EDLC application. The porous membrane used in present study was epidermis of onion (onion peel membrane) and low viscosity ionic liquid (IL) i.e. 1-ethyl 3-methyl imidazolium thiocynate. The electrical, structural, optical characterization was carried out in detail. The optical micrographs show addition in amorphosity with adding IL. Fourier transform infrared spectroscopy (FTIR) revealed the interaction between ionic liquid and membrane as well as composite nature of membrane electrolyte. Impedance spectroscopy revealed the twofold enhancement in conductivity value by doping IL. Electrical double layer supercapacitor (EDLC) has been fabricated using carbon nanotube (CNT). Cyclic voltammetry and low frequency impedance spectroscopy data further affirm the reasonable value of specific capacitance (Csp = 9.2F/g).

Novel heterostructure photocatalyst built from titanium dioxide (TiO2), graphene oxide (GO) and indium sulfide (In2S3) has been successfully prepared for photoelectrochemical hydrogen production. The stepwise introduction of three materials on conductive glass substrate has been realized through hydrothermal, electrochimical and spin coating deposition methods, respectively. The structure, morphology, composition, optical and photoelectrochemical properties of the resultant photoanodes were investigated in detail. The presence of GO in the heterostructure film was confirmed by Raman analysis with D and G band intensity. Surface morphology analysis of the GO/In2S3/TiO2 NRs structure reveal the homogenous distribution of graphene oxide on In2S3/TiO2 NRs surface. From UV–Vis analysis, band gap energy of the samples decreases gradually from 3.34 eV (TiO2 NRs) to 3.12 eV, with In2S3 and GO addition. The electrochemical impedance spectroscopy (EIS) further confirmed that GO/In2S3/TiO2NRs heterostructure possessed the lowest charge-transfer resistance, revealing that In2S3 and GO could significantly accelerate the electron mobility compared with bare TiO2. From Mott-Schottky plots, several parameters such as flat-band potential and free carrier concentration were determined. Next, The GO/In2S3/TiO2 NRs electrode achieved remarkably improved current density (0.45 mAcm2 at 0.8 V vs Ag/AgCl) compared to pure TiO2 NRs or In2S3/TiO2 NRs electrodes, which attributes to the uniform structure and excellent electrical conductivity of GO, which could reduce the combination rate of the photo electron-hole pairs. These results reveal that GO/In2S3/TiO2 NRs possesses great potential toward the development of newly synthesizable catalysts in the field of photoelectrochemical water splitting.

The lithium halide doped phosphate glass system was investigated using LiCl as an additive halide. Glass of composition (1-x) (0.5LiCl–0.5Li2O)–xP2O5 with x = 0.65; 0.60; 0.55 and 0.50 were prepared by the melt quench method. Electrical conductivity measurements were made in the temperature range from RT to 383 K using the impedance spectroscopy technique. The frequency dependence as well as the electrical modulus of the glasses are investigated. The results showed that the conduction mechanism in these glasses is governed by the correlated barrier hopping (CBH) mechanism and the conductivity relaxation is of the non-Debye type.

Polymers have exhibited a promising ability for the corrosion protection of metals. In the present study, poly(o-anisidine) (POA) nanoparticles and its nanocomposites with silicon dioxide (SiO2) like POA/SiO2 containing different compositions content of SiO2 (5%, 10% & 15% w/w) were prepared by chemical oxidative polymerization. FT-IR spectra of POA/SiO2 composites indicate the presence of SiO2 nanoparticles in the polymer nanocomposites. The X-ray diffraction (XRD) studies was showed more crystalline behavior of polymer nanocomposites and the particle grain size was calculated using Scherer’s formula and it was found to be within nano range. The surface morphology of the polymer composites were investigated by Scanning Electron Microscopy (SEM). Energy dispersive X-ray spectroscopy (EDS) confirms the incorporation of silicon and oxygen in the polymer nanocomposites. Further the synthesized polymeric composites were introduced into acrylic resin and the polymer/SiO2/acrylic hybrid materials were applied on the surface of mild steel sample. The corrosion efficiency and corrosion rate of the polymer nanocomposites were calculated for mild steel in 3.5% NaCl solution using Polarization curve and Electrochemical Impedance Spectroscopy (EIS).

The B-site-doping method of barium titanate (BaTiO3) is one of the promising route to prepare lead-free materials with enhanced dielectric and piezoelectric properties. Lead-free (Ba0.85 Ca0.15)(Zr0.1-xSnxTi0.9)O3 [BCZT:Sn] (x = 0, 0.02, 0.04 and 0.06) ceramics were synthesized using the sol-gel method. The effects of Sn content on the energy-storage performance and electric conduction mechanisms of BCZT ceramic were systematically investigated. The energy storage performance investigation showed that the recoverable energy storage has been enhanced with Sn doping rate, the composition doped x = 0.02 (BCZT: 2Sn) depicted the highest recoverable energy density and efficiency (Wrec = 19 mJ/cm3, ɳ = 81.65%). The electrical properties of the BCZT:Sn ceramics were investigated using the impedance spectroscopy technique at temperature range of 25–450 °C. The net impedance of the samples showed a significant enhancement as the Sn content increases, owing to the lattice distortion created by the relative difference in the radius of Sn4+and Zr4+ and different outer electronic shells. The AC conductivity was measured and analyzed as a function of frequency and temperature. Obtained activation energy values were associated with possible conduction mechanisms.

The demand for alternative power sources for perceiving sustainable/clean energy has created an increasing interest and becoming more critical owing to the development of applications such as electric vehicles and new type of portable electronic devices currently available in the market. In this regard, relatively safe nature of all solid state batteries (ASSB) makes it distinct as a viable battery over the battery research scenario. Improvement of the technology predominantly depends on the solid electrolyte material employed in the batteries. A very good solid electrolyte must have high ionic conductivity as well as a wide electrochemical window. Lithium Lanthanum Zirconate (LLZO) is one of the promising electrolyte materials for All Solid State Batteries (ASSB). In the present work, LLZO powders have been prepared via a solution route synthesis. The morphology and the purity of the samples were analysed using X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X-ray Spectroscopy (EDS) analysis (EIS). The ionic conductivities of the samples were investigated using alternating current Electrochemical Impedance Spectroscopy. UV–vis Spectroscopy was employed to determine the optical band gap of LLZO, and the value (∼6 V) was in agreement with the potential window of LLZO available in the literature. The high potential window and good ionic conducting properties shows that LLZO is a better alternative electrolyte material for next generation solid-state assemblies.

Considerable efforts are being made to find cheaper and more efficient alternatives to the currently commercially available catalysts based on precious metals for the Hydrogen Evolution Reaction (HER). In this context, fullerenes have started to gain attention due to their suitable electronic properties and relatively easy functionalization. We found that the covalent functionalization of C60, C70 and Sc3N@IhC80 with diazonium salts endows the fullerene cages with ultra-active charge polarization centers, which are located near the carbon-diazonium bond and improve the efficiency towards the molecular generation of hydrogen. To support our findings, Electrochemical Impedance Spectroscopy (EIS), double layer capacitance (Cdl) and Mott-Schottky approximation were performed. Among all the functionalized fullerenes, DPySc3N@IhC80 exhibited a very low onset potential (-0.025 V vs RHE) value, which is due to the influence of the inner cluster on the extra improvement of the electronic density states of the catalytic sites. For the first time, the covalent assembly of fullerenes and diazonium groups was used as an electron polarization strategy to build superior molecular HER catalytic systems.

Nanocomposite polymer electrolytes (NCPE) have been prepared by blending poly (ethylene oxide) (PEO) and polyhedral oligomeric silsesquioxane-functionalized with poly (ethylene glycol) (POSS-PEG) with lithium tetrafluoroborate (LiBF4). NCPE has been characterized by DSC and impedance analyzer. POSS-PEG was highly compatible with PEO up to 50 wt% and resulted in single Tg and increased ionic conductivity. The ionic conductivity of the nanocomposites increased to 4.02 × 10−6 S/cm at POSS-PEG 50 wt% by more than 2 orders of magnitude. POSS-PEG nanoparticles sustainably increased ionic conductivity without impeding chain motion of polymer and were highly compatible with PEO up to POSS-PEG 50 wt%, which can mitigate the restriction of the amount of nanoparticles introduction. Also, the stable POSS core structure supplements the mechanical properties of polymer electrolytes. To understand ion transport behaviors, the segmental relaxation times ( τ s) of nanocomposites were studied by dielectric spectroscopy as function of POSS-PEG loading. τ s decreased to −1.54 from −1.01 at POSS-PEG 5 ∼20 wt%, but it slightly increased to −1.28 from −1.54 at POSS-PEG 40 ∼ 50 wt%, which could be attributed to bridged complex formed between PEO and POSS-PEG through Li+.

Sr surface segregation has been one of the main reasons for the cathode performance degradation during the long-term operation of solid oxide fuel cells (SOFC). Investigation on Sr segregation mechanism and proposing strategies on suppressing the Sr surface segregation are significant for SOFC development. In this paper, La0.8Sr0.2Co0.2Fe0.8-xNbxO3-δ (LSCFNb, x = 0, 0.02, 0.04, 0.06, 0.08 and 0.1) are prepared via sol-gel method. The electrochemical performance and long-term stability are tested through electrochemical impedance spectroscopy (EIS) and constant current polarization. The results show that the long-term stability of LSCFNb cathodes are strongly affected by Nb content. Combining the results of ICP and XPS, it's revealed that the Sr surface segregation can be effectively suppressed with the increase of Nb content. The LSCFNb cathodes gain the optimal electrochemical performance when x = 0.04, with minimum polarization resistance of 0.27 Ω cm2 at 750 °C and oxygen reduction reaction activation energy of 1.54 eV. After cathodic polarization for 144 h, the polarization resistance and activation energy of LSCFNb4 cathode increase slightly, revealing it a promising cathode material for SOFC research.

This study had dealt with the resistance to corrosion with nanostructured materials since they consume less energy and was employed in a variety of lightweight applications. For this study, nano-sized cerium oxide had been used as an anti-corrosive inhibition. This CeO2 nanoparticle was synthesized utilizing a hydrothermal technique. The coating was obtained by mixing various concentrations of CeO2 nanoparticles with a water-based epoxy resin. Resistance to corrosion with the formulated coating on a mild steel substrate was tested inside a simulated concrete pore solution containing 0.5 M NaCl solution. The corrosion inhibiting effect was evaluated by immersing the nano CeO2 – Epoxy composite coated mild steel substrate in a simulated concrete pore solution utilizing electrochemical impedance spectroscopy methodology. Tafel tests were used to calculate the corrosion rate. The outcomes showed that the nano-sized cerium oxide as filler material for epoxy covering displayed a superior corrosion inhibiting effect along with the commencement of a stable protective shield when compared to substrate of pure epoxy and without coating.