Potential Applications In Electrochemical Devices Research Articles

Ion Conduction Mechanism in Polymer Blend Electrolyte Films

AbstractThis paper presents the development of the blend polymer solid electrolyte films (BPSE) for potential applications in electrochemical devices. Two host polymers, polyvinyl alcohol (PVA) and polymethyl methacrylate (PMMA), along with the salt KI, are employed to create the solid polymer electrolytes (SPEs). The synthesis involves varying the weight percentage of salt within the SPEs to investigate its impact on the material properties. Conductivity measurements are conducted using AC impedance spectroscopy, unveiling the conductivity behavior of the BPSEs. Additionally, surface morphology is characterized using polarized optical microscopy (POM) at 10 pixel resolution, offering a detailed examination of the film's microstructure. This comprehensive study not only contributes to the understanding of the fundamental properties of BPSEs but also opens avenues for their utilization in various electrochemical applications.

Harmonizing Energies: The Interplay Between a Nonplanar SalEn-Type Molecule and a TEMPO Moiety in a New Hybrid Energy-Storing Redox-Conducting Polymer.

Redox-conducting polymers based on SalEn-type complexes have attracted considerable attention due to their potential applications in electrochemical devices. However, their charge transfer mechanisms, physical and electrochemical properties remain unclear, hindering their rational design and optimization. This study aims to establish the influence of monomer geometry on the polymer's properties by investigating the properties of novel nonplanar SalEn-type complexes, poly[N,N'-bis(salicylidene)propylene-2-(hydroxy)diaminonickel(II)], and its analog with 2,2,6,6-tetramethylpiperidinyl-N-oxyl (TEMPO)-substituted bridge (MTS). To elucidate the charge transfer mechanism, operando UV-Vis spectroelectrochemical analysis, electrochemical impedance spectroscopy, and electron paramagnetic resonance are employed. Introducing TEMPO into the bridge moiety enhanced the specific capacity of the poly(MTS) material to 95mA h g-1, attributed to TEMPO's and conductive backbone's charge storage capabilities. Replacement of the ethylenediimino-bridge with a 1,3-propylenediimino- bridge induced significant changes in the complex geometry and material's morphology, electrochemical, and spectral properties. At nearly the same potential, polaron and bipolaron particles emerged, suggesting intriguing features at the overlap point of the electroactivity potentials ranges of polaron-bipolaron and TEMPO, such as a disruption in the connection between TEMPO and the conjugation chain or intramolecular charge transfer. These results offer valuable insights for optimizing strategies to create organic materials with tailored properties for use in catalysis and battery applications.

A novel protonic ceramic fuel cell with SrSn0.8Sc0.2O3-δ electrolyte

The recent discovery of SrSn0.8Sc0.2O3-δ (SSS) perovskite oxide as a promising proton-conducting material has generated interest in its potential application in electrochemical devices as PCFCs. This study assesses the feasibility of SSS in PCFCs by its stability, density, chemical compatibility, and electrochemical performance. The study demonstrated the favorable stability of SSS even after reduction at 800 °C under H2 for 24 h as well as immersion in boiling water for 5 h. The relative density of SSS could easily exceed 94% after sintering with NiO aid at 1400 °C. The chemical compatibility and electrochemical performance of SSS were investigated with various electrode materials. The BaCo0.4Fe0.4Zr0.1Y0.1O3-δ exhibited relatively better electrochemical performance with SSS. The electrolyte was co-sintered with a Ni-based anode substrate and densified to high density at 1450 °C without sintering aids. The fuel cell utilizing an anode-supported Ni-SSS|SSS|BCFZY-SSS configuration exhibited a peak power density of 432.1 mW cm−2 at 800 °C.

Interfacial molecular structure of phosphazene-based polymer electrolyte at the air-aqueous interface using sum frequency generation vibrational spectroscopy

The change induced in the physicochemical properties of polymer while hosting ions provides a platform for studying its potential applications in electrochemical devices, water treatment plants, and materials engineering science. The ability to host ions is limited in very few polymers, which lack a detailed molecular-level understanding for showcasing the polymer-ion linkage behavior at the interfacial region. In the present manuscript, we have employed sum frequency generation (SFG) vibrational spectroscopy to investigate the interfacial structure of a new class phosphazene-based methoxyethoxyethoxyphosphazene (MEEP) polymer in the presence of lithium chloride salt at the air-aqueous interface. The interfacial aspects of the molecular system collected through SFG spectral signatures reveal enhanced water ordering and relative hydrogen bonding strength at the air-aqueous interface. The careful observation of the study finds a synchronous contribution of van der Waals and electrostatic forces in facilitating changes in the interfacial water structure that are susceptible to MEEP concentration in the presence of ions. The observation indicates that dilute MEEP concentrations support the role of electrostatic interaction, leading to an ordered water structure in proximity to diffused ions at the interfacial region. Conversely, higher MEEP concentrations promote the dominance of van der Waals interactions at the air-aqueous interface. Our study highlights the establishment of polymer electrolyte (PE) characteristics mediated by intermolecular interactions, as observed through the spectral signatures witnessed at the air-aqueous interface. The investigation illustrates the polymer-ion linkage adsorption effects at the interfacial region, which explains the macroscopic changes observed from the cyclic voltammetry studies. The fundamental findings from our studies can be helpful in the design and fine-tuning of better PE systems that can offer improved hydrophobic membranes and interface stability for use in electrochemical-based power sources.

Entropy stabilization of two-dimensional transition metal dichalcogenide alloys: A density functional theory study

As high-entropy alloying provides an increasingly important avenue for widening the set of functional materials for a variety of applications, it is useful to uncover synthesis routes that do not rely on large temperatures for achieving entropic stabilization. Focusing on transition-metal dichalcogenides, we present direct computational evidence from density functional theory calculations that high-entropy disulfide (HES) alloys with five cations from groups 4–6 are thermodynamically stable at temperatures routinely achievable in conventional deposition systems. While all 126 sulfide combinations with five group 4–6 transition metals are thermodynamically favorable at low (<800 K) or medium (<1200 K) temperatures, we show that electronegativities, valence electron concentrations, and atomic radii of cations can help predict whether an HES alloy is stable in the 1-H or the 1-T structure. Furthermore, replacing one of the five cations with another, from outside groups 4–6, can still yield HES alloys with nearly planar layer morphologies and stabilization temperatures below 1200 K, albeit with some localized defects. These results demonstrate that a wide range of stable HES alloys can be synthesized experimentally as 2D layers, thereby providing facile ways for expanding the materials’ space with potential applications in electrochemical devices, catalysis, energy storage, or sensing.

Crystal Structures of Two Titanium Phosphate-Based Proton Conductors: Ab Initio Structure Solution and Materials Properties.

Transition-metal phosphates show a wide range of chemical compositions, variations of the valence states, and crystal structures. They are commercially used as solid-state catalysts, cathode materials in rechargeable batteries, or potential candidates for proton-exchange membranes in fuel cells. Here, we report on the successful ab initio structure determination of two novel titanium pyrophosphates, Ti(III)p and Ti(IV)p, from powder X-ray diffraction (PXRD) data. The low-symmetry space groups P21/c for Ti(III)p and P1̅ for Ti(IV)p required the combination of spectroscopic and diffraction techniques for structure determination. In Ti(III)p, trivalent titanium ions occupy the center of TiO6 polyhedra, coordinated by five pyrophosphate groups, one of them as a bidentate ligand. This secondary coordination causes the formation of one-dimensional six-membered ring channels with a diameter dmax of 3.93(2) Å, which is stabilized by NH4+ ions. Annealing Ti(III)p in inert atmospheres results in the formation of a new compound, denoted as Ti(IV)p. The structure of this compound shows a similar three-dimensional framework consisting of [PO4]3– tetrahedra and TiIV+O6 octahedra and an empty one-dimensional channel with a diameter dmax of 5.07(1) Å. The in situ PXRD of the transformation of Ti(III)p to Ti(IV)p reveals a two-step mechanism, i.e., the decomposition of NH4+ ions in a first step and subsequent structure relaxation. The specific proton conductivity and activation energy of the proton migration of Ti(III)p, governed by the Grotthus mechanism, belong to the highest and lowest, respectively, ever reported for this class of materials, which reveals its potential application in electrochemical devices like fuel cells and water electrolyzers in the intermediate temperature range.

Phase transformation and ionic conductivity mechanism of a low-temperature sintering semiconductor Na2CaV4O12

Alkaline earth metal vanadates have drawn attention because of their potential applications in electrochemical devices. Here, Na2CaV4O12 was prepared at extremely low temperatures (350–550 °C) and showed a semiconductor behavior with a bandgap of 2.92 eV. A phase transition from P4/nbm to P4̅b2 occurred at 510 °C was identified by an in-situ XRD upon heating, where the 16 n site for oxygen atoms in the P4/nbm phase evolves into two distinguishable 8i sites in the P4̅b2 phase. Ionic conduction in Na2CaV4O12 at elevated temperatures was reported for the first time in the present work. A strong correlation between ionic conductivity and phase structure of Na2CaV4O12 is observed. The charged carriers are mainly sodium ions for the low-temperature P4/nbm phase, while mixed conduction contributed by sodium ions and oxide ions happened in the transformed phase. Bond valence-based energy landscape calculations disclosed a two-dimensional interstitial diffusion mechanism for Na+ ions in the Na2Ca-layers, as well as a two-dimensional diffusion mechanism for oxide ions in the V4O12-layers. The novel semiconductor ceramic would have potential applications in all-solid sodium ions batteries or solid oxide fuel cells as electrolytes.

Imidazolium zwitterion‐based protic ionic liquids: from monomers to polymer membranes

AbstractWe present the results of synthesis and investigation of the thermal behavior, ion transport properties and electrochemical stability of polymerized imidazolium‐based protic ionic liquids (poly(ILs)) as materials with potential applications in electrochemical devices. The phase behavior of both poly(ILs) and the corresponding IL monomers (MILs) was studied using differential scanning calorimetry and thermogravimetric analysis. The temperature dependences of the conductivity and electrochemical window of all the MILs and poly(ILs) are discussed. © 2021 Society of Chemical Industry

Fabrication of Electrically Conductive Cellulose Acetate/Polyaniline/WO3 Nanocomposite Nanofibers with Potential Applications in Electrochemical Devices

In this work, due to the importance of biopolymers utilization in electrochemical applications, a new type of electroconductive/electroactive cellulose acetate (CA) base nanofibers is prepared via electrospinning of acid-doped polyaniline (PANI), WO3 nanopowders and CA. The fabricated nanocomposite mats were evaluated and characterized using various techniques such as scanning electron microscopy (SEM), cyclic voltammetry (CV), differential scanning calorimetry (DSC), electrochemical impedance spectroscopy (EIS), Fourier infrared spectroscopy (FTIR) and X-ray diffraction (XRD). SEM images indicated that the nanofibers morphology was ribbon-like, smooth and bead free that may be due to solvent system selection and ambient conditions. Also, the average diameter of CA nanofibers has been decreased from 320 to 230 nm by adding 5 wt % of PANI to CA solution. FTIR results confirmed the existence of hydrogen interaction between the polyaniline and CA molecular chains. The results obtained from XRD and DSC showed that crystalline region of CA/PANI mats has increased by addition of WO3 nanoparticles. Electrochemical analysis showed good electrocatalytic properties for the electrospun CA/PANI/WO3 nanocomposite nanofibers. The results indicated that charge transfer and ohmic serial resistance of the nanocomposites were decreased due to addition of PANI and WO3 nanoparticles.

Hydrothermal synthesis of novel Ni microflowers with enhanced ferromagnetic properties

Novel nickel microflowers assembled with many thin nanoplates were synthesised through a simple hydrothermal method using sodium hypophosphite as a green reducing reagent. Sodium tartrate served as a complexing reagent and cetyltrimethylammonium bromide (CTAB) was used as a surfactant. It was found that the amount of sodium hydroxide played a key role in determining both the shape and to further the self-assembly process of nickel flowers. Such a flower-like nickel microstructure shows a great enhancement of the ferromagnetic properties with a coercivity of 308.7 Oe, which may be ascribed to the distinctive two-dimensional (2D) anisotropic structure of the nanoplates and the final hierarchically flower-like shape. This work presents a preferred approach to fabricate high-quality magnetic nickel microflowers which have potential applications in electrochemical devices, magnetic sensors, and catalytic agents.

Investigation on transport and thermal studies of solid polymer electrolyte based on carboxymethyl cellulose doped ammonium thiocyanate for potential application in electrochemical devices

In this work, a free standing and flexible solid polymer electrolyte (SPE) based on non-hazardous and environmental friendly material, carboxymethyl cellulose (CMC) was successfully produced in order to overcome environmental and pollution issues. The effect of doping ammonium thiocyanate (NH4SCN) into SPE based on carboxymethyl cellulose (CMC) on transport, thermal and electrochemical stability window properties have been investigated for potential application in electrochemical devices. CMC-NH4SCN SPE was prepared via solution casting technique. The properties of the prepared CMC-NH4SCN SPE were characterized via Fourier transform infrared spectroscopy (FTIR) deconvolution, transference number measurement (TNM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and linear sweep voltammetry (LSV) techniques. FTIR deconvolution was performed in order to investigate the dissociation of ions and transport properties of CMC-NH4SCN SPE system and it can be correlated with the ionic conductivity of CMC-NH4SCN SPE system. The result of TNM was obtained via a DC polarization method where the ionic transference number for the highest conducting CMC-NH4SCN SPE was found to be 0.93. Thus, it can be suggested that the conducting species for the highest conducting CMC-NH4SCN SPE are mainly due to ions. TGA was performed to investigate the thermal stability of CMC-NH4SCN SPE. The value of glass transition temperature of CMC-NH4SCN SPE was obtained from DSC analysis. Electrochemical stability window of the highest conducting CMC-NH4SCN SPE obtained from LSV technique was up to 1.6 V. As a result, it can be inferred that the highest conducting CMC-NH4SCN SPE had shown a promising performance and has a great potential to be applied in electrochemical devices application such as proton batteries.

THE EFFECT OF TEMPERATURE ON THE CONDUCTIVITY OF POLYMER FILMS

The effects of temperature on PVA (Poly Vinyl Alcohol) based organic blends containing chlorine have been studied for their potential applications in electrochemical devices. The composite polymers PVA-Chloral Hydrate (CH) blends were blended separately with 23, 34, 45 and 57% CH. The composite films were prepared by solvent-casting method and each film has been heated different temperature up to 353 K. The electrical properties have been studied using LCR meter and impedance analyzer in the frequency range from 20 Hz to 1 MHz. The conductivity-temperature relation study revealed that an increase conductivity of the PVA-CH blends with increasing temperature up to 353 K. The increase of conductivity with temperature is attributed to the increase of free ion mobility due to thermal energy kT and possible more ions gained kinetic energy via the thermally activated hopping of charge carriers between trapping sites and phonon-assisted quantum tunneling through a barrier separating two equilibrium positions. The conductivity activation energy obtained decreases with the blend composition increases.Keywords: Influence, Temperature, Conductivity, Polymer Films

Mechanical properties of 1 mol% CeO2‐10 mol% Sc2O3 co‐doped and stabilized ZrO2 synthesized through hydro/solve‐thermal method

AbstractUltra‐fine 1 mol% CeO2‐10 mol% Sc2O3 co‐doped and stabilized ZrO2 (1Ce10ScSZ) powders with average grain size less than 10 nm in diameter were prepared by hydro/solve‐thermal method using either deionized water, ethanol, or methanol as solvent. As‐synthesized powders were characterized in terms of phase structure, particle morphology, and chemical composition by X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), high‐resolution transmission electron microscopy (HRTEM), and inductively coupled plasma‐optical emission spectroscopy (ICP‐OES), respectively. Sintering studying was conducted on pellets of 15 mm in diameter and 3 mm in thickness under uniaxial compaction using 25 MPa at either 600, 800, 1000, 1100, 1200, 1400, or 1500°C for 1 hour. Phase transitions and grain morphologies of those sintered samples were characterized by XRD and field emission scanning electron microscopy (FESEM). Mechanical properties were characterized on dense pellets sintered at 1500°C by nanoindentation. Experimental results showed that ethanol was more effective to synthesize agglomerate‐free 1Ce10ScSZ powders as compared with deionized water and methanol. Choice of solvent affected the environment of hydro/solve‐thermal solution, which led to variation of chemical compositions of powders and porosities of sintered pellets, and therefore, influenced their mechanical performance. Our study showed that solvent was important to make dense, thin, and mechanically robust 1Ce10ScSZ electrolyte for potential applications in electrochemical devices. Absolute values of hardness (H) and Young's modulus (E) measured from our samples are much higher and more consistence than those results obtained from commercial vendors reported in literatures.

Investigation of biosourced carboxymethyl cellulose-ionic liquid polymer electrolytes for potential application in electrochemical devices

Biosourced carboxymethyl cellulose polymer electrolytes have been studied for potential application in electrochemical devices. The carboxymethyl cellulose was obtained by reacting cellulose derived from kenaf fibre with monochloroacetic acid. Films of the biosourced polymer electrolytes were prepared by solution-casting technique using ammonium acetate salt and (1-butyl)trimethyl ammonium bis(trifluoromethylsulfonyl)imide ionic liquid as charge carrier contributor and plasticizer, respectively. The shift of peak of carboxyl stretching in the Fourier transform infrared spectra confirmed the interactions between the host biosourced polymer with the ionic liquid. Scanning electron microscopy indicated that the incorporation of ionic liquid changed the morphology of the electrolyte films. The room temperature conductivity determined using impedance spectroscopic technique for the film without ionic liquid was 6.31 × 10−4 S cm−1 while the highest conductivity of 2.18 × 10−3 S cm−1 was achieved by the film integrated with 20 wt% (1-butyl)trimethylammonium bis(trifluoromethanesulfonyl) imide. This proved that the incorporation of ionic liquid into the salted system improved the conductivity. The improvement in conductivity was due to an increase in ion mobility. The results of linear sweep voltammetry showed that the electrolyte was electrochemically stable up to 3.07 V.

Synthesis of High-Aspect-Ratio Nickel Nanowires by Dropping Method.

A facile and high-yield route, dropping method, has been used to synthesize Ni nanowires (NWs) with a high aspect ratio. Compared to the conventional chemical reduction method, the diameter of Ni NWs prepared by the dropping method distinctively decreased and the surface roughness was improved. After optimizing the process parameters such as the Ni ion concentration and volume of the dropped NiCl2·6H2O solution, the diameter and aspect ratio of the NWs are 70 nm and ~600, respectively. The possible synthesized process of the dropping method was discussed. This work presents a preferred approach to fabricate high-quality one-dimensional magnetic materials which have potential applications in electrochemical devices, magnetic sensors, and catalytic agents.

Effects of Gamma Radiation on Electrical Conductivity of PVA-CH Composites

Keywords: Gamma radiation, electrical conductivity, PVA-CH compositesAbstract.The effects of radiation on polymer composite PVA-based organic blends containing chlorine have been studied for their potential applications in electrochemical devices. The polymer composite PVA-Chloral Hydrate (CH) were blended separately with 23, 34, 45 and 57% CH. The composite films were prepared by solvent-casting method and each film has been irradiated with g-rays at different doses up to 12 kGy. The electrical properties have been studied using an impedance analyzer of LCR meter in the frequency range from 20 Hz to 1 MHz. The conductivity-dose relation study revealed that increase in conductivity of the irradiated PVA-CH blends with increasing dose up to 12 kGy. The increase in the conductivity with dose is attributed to the increase of ionic carriers in the composites induced by radiation scission of CH molecules and also due to hydrolysis of water.

Properties of Stannum-Based Li-NASICON-Structured Solid Electrolytes for Potential Application in Electrochemical Devices

Properties of Stannum-Based Li-NASICON-Structured Solid Electrolytes for Potential Application in Electrochemical Devices

Structural and DC Ionic conductivity studies of carboxy methylcellulose doped with ammonium nitrate as solid polymer electrolytes

Solid polymer electrolytes have been prepared by solution casting technique. Carboxy methylcellulose (CMC)-ammonium nitrate (AN) films were studied with varied AN salt concentration from 5-50 wt.% at ambient temperature. X-ray diffraction (XRD) pattern shows the amorphous nature of polymer electrolyte samples. IR-spectra confirm the polymer-salt complexes in the range of 1633 - 829 cm-1. Impedance analysis reveals that polymer electrolyte film containing 45wt.% AN exhibits the highest ionic conductivity of (7.71 ± 0.04) x10-3 Scm-1, while pure CMC film gives the lowest ionic conductivity of (1.86 ± 0.03) x10-8 Scm-1. It was evident from this study that the increase of ionic conductivity depends on the AN salt concentration. The present polymer-salt system has potential application in electrochemical devices based on the results obtained. Key words: Carboxy methylcellulose, ammonium nitrate, solid polymer electrolytes, ionic conductivity.

Silk-Ion Jelly: a novel ion conducting polymeric material with high conductivity and excellent mechanical stability

In this work, a thin, flexible and mechanically stable polymer conducting material (Silk-Ion Jelly) was developed though application of Ion Jelly on to silk fabrics. Ion Jelly was prepared through jellification of a room temperature ionic liquid, 1-butyl-3-methyl-imidazolium dicyanamide ([bmim][dca]) using gelatin and water and applied to silk fabrics using two different processes: impregnation and in-situ. Various parameters influencing ionic conductivity such as Ion Jelly composition (ratio of [bmim][dca], water and gelatin) and incorporation as well as the type of application process were thoroughly investigated. It was observed that the Ion Jelly compositions containing lower gelatin and water ratio as well as application through in-situ process at high temperature (200 °C) led to considerable improvement in conductivity, mainly due to increased [bmim][dca] concentration, structural flexibility and reduced silk crystallinity. Silk-Ion Jelly prepared using optimized conditions showed excellent mechanical stability and possessed high room temperature conductivity (2.9 × 10−3 S. cm−1), similar to [bmim][dca], and therefore, this novel ion conducting material may find potential applications in electrochemical devices due to its eco-friendly preparation route using biomaterials and green solvents. Copyright © 2012 John Wiley & Sons, Ltd.

Implementation of a diffusion-limited aggregation model in the simulation of fractals in PVDF-HFP/PEMA–NH4CF3SO3–Cr2O3 nanocomposite polymer electrolyte films

We initially prepared films of poly(vinylidene fluoride-co-hexafluoropropylene)/poly(ethyl methacrylate)–ammonium trifluorome–thanesulfonate dispersed with various wt.% of chromium oxide to study their properties and potential application in electrochemical devices. However, a few months later the nanocomposite polymer electrolyte membranes were found to become a sort of medium for fractal growth. This discovery led to a simulation of the fractals observed in these polymer electrolyte films using a diffusion-limited aggregation model that is based on Brownian motion theory (random walk). The fractal dimensions, D, of the fractal patterns obtained from experimental and simulation work were calculated using the box-counting method. The fractal patterns and dimensions of the simulated fractal patterns were comparable with those obtained from the original fractals observed in the polymer electrolyte films.