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The use of solid polymer electrolytes is a novel and promising approach for enhancing the safety of lithium-ion and sodium-ion batteries. A number of publications on manufacturing electrolytes with lithium-ion and sodium-ion conductivity based on Nafion-like polymers have appeared in recent decade. The present mini-review analyses various methods of the synthesis of such electrolytes and their properties, as well as the information on laboratory lithium-ion and sodium-ion batteries using such electrolytes. The conclusion is made that the use of Nafion-based solid polymer electrolytes with Li+ and Na+ cation conductivity opens the way to creation of a new generation of lithium-ion and sodium-ion batteries. The principal advantage of Nafion-based solid polymer electrolytes over traditional PEO-based electrolytes is a fairly high cation transport number, which provides a sharp decrease in concentration polarization and, consequently, the increase in the energy efficiency of batteries.

In this study, a series of novel composite membranes were synthesized utilizing polyethersulfone (PES), sulfonated polyethersulfone (SPES) as base polymer and titanium tungstomolybdate (TWM) as an inorganic ion exchange resin. The membranes were fabricated through the solution casting technique. The composite membranes exhibited enhanced thermal and chemical stability, as well as improved oxidative stability. All the composite membranes demonstrated higher hydrophilicity, with the SPES-TWM composite membranes displaying the lowest contact angle of 65°. The composite membranes also displayed favorable water uptake (up to 26% for SPES-TWM) and lower methanol uptake (maximum 12% for SPES-TWM) and better mechanical stability (maximum of 40 MPa for SPES-TWM). The SPES-TWM composite membranes exhibited the maximum ion exchange capacity of 1.32 meq.g−1. The transport number of 0.95 was obtained for SPES-TWM, which is comparable to the Nafion-117 membrane. The proton conductivity of both membranes increased as the temperature increased. The maximum proton conductivity of 6.3 mScm−1 was observed for SPES-TWM at 60 °C. • Composite membranes based on PES and SPES with nano TWM were prepared. • Composite membranes exhibited thermal stability up to 220 °C, mechanical stability of 44 MPa and good oxidative stability. • SPES-TWM membrane exhibited an IEC of 1.32 meqg−1 and proton conductivity of 6.3 mScm−1 at 60 °C. • SPES-TWM membrane exhibited higher diffusivity and permselectivity than PES-TWM membrane. • PES-TWM membrane displayed methanol permeation of 5.28 × 10−7 cm2s−1. [ABSTRACT FROM AUTHOR]

A perovskite-structured proton conductor, CaHf 0.9 In 0.1 O 2.95 , was synthesized via solid-state reaction, and proton conductivity and transport number of its grain interior were determined by using the defect equilibria model. The results reveal that the total conductivity of grain interior and the entire sample (grains and grain boundaries) of CaHf 0.9 In 0.1 O 2.95 , respectively, reaches 7.26 × 10−4 S∙cm−1 and 3.03 × 10−4 S∙cm−1 in a humid atmosphere at 800 °C. Moreover, it was observed that the conductivities of the grain interior exhibited higher values than those of the entire sample within the temperature range of 400–800 °C. The activation energy of the entire sample was higher than that of the grain interior; and for the charge carriers of CaHf 0.9 In 0.1 O 2.95 , the activation energy of oxygen vacancies and holes was higher than that of the proton. At 400–800 °C, transport properties of CaHf 0.9 In 0.1 O 2.95 were dominated by proton conduction under the atmosphere containing oxygen and water vapor, where the transport numbers of proton in the grain interior and the entire sample were estimated to be 0.541 and 0.497, respectively, at a temperature of 800 °C. Thus, the proton transport number of grain interior was found to be higher than that of the entire sample. Therefore, the grain interior of CaHf 0.9 In 0.1 O 2.95 can provide better proton conduction than grain boundary. In summary, these results exhibit that CaHf 0.9 In 0.1 O 2.95 possesses certain application prospects in electrochemical sensors. [ABSTRACT FROM AUTHOR]

PVC-Derived nickel cobalt molybdophosphate (NCMP) composite membrane showed mechanical and thermal stability. The hydrothermal technique was used to synthesize the composite material. The ability to control membrane properties by changing the polymer to porous support ratio is a significant advantage of utilizing inorganic. Ion-exchange ability was controlled by chemical characterization TGA, FTIR and SEM with EDX analyses confirming the composition, thermal stability, superficial morphology, porosity, functional groups and ion transport of the composite. The chemical potential was measured using strong electrolytes such as KCl, NaCl, KNO3 and NaNO3. The estimated membrane charge density was calculated for membrane performance. Membrane characteristics like transport number, mobility ratio, and charge efficiency, were determined using the Teorell–Meyer–Sievers theory framework. These characteristics enable the hybrid membrane to be an efficient component in a wide range of electro-membrane execution. Sodium ion extraction and removal efficiency and industrial uses of the NCMP/PVC composite membrane should be investigated. [ABSTRACT FROM AUTHOR]

Polyvinyl chloride (PVC)-derived cobalt molybdophosphate (CMP) nanocomposite material was synthesized by sol-gel technique. The physico-chemical properties such as composition, functional groups, thermal stability, phase transition, and surface structure were characterized using TGA, FT-IR, SEM, and TEM analyses. Membranes from the nanocomposite material were prepared to elucidate the electrochemical properties. The ionic potential was measured using strong electrolytes such as KCl, NaCl, and LiCl. Electrolytes have the following cation-sequenced with observed membrane potentials Li+ > Na+ > K+. The estimated membrane charge density was calculated for membrane performance. Membrane characteristics, such as transport number, mobility ratio, and charge efficiency, were determined using the Teorell–Meyer–Sievers (TMS) theory framework. LiCl has the highest value of t+ and ω ¯ . The nanocomposite membrane is lithium cation-selective, which can, therefore, be effectively utilized in various electro-membrane processes such as lithium-ion extraction and removal. [ABSTRACT FROM AUTHOR]

Flexible solid polymer electrolytes (SPEs) constitute an emerging class of safe and prospective electrolytes to be used in next-generation all solid-state energy storage devices. The present work is an attempt to incorporate organic nanofillers like carbon dots derived from glucose (g-CDs), in a benign polymer blend PVA-PEG with NaCl as the dopant salt and to establish the effect of organic nanofillers on the physico-chemical properties of the blend and the ionic conductivity and ion transport mechanism within the blend polymer. For the free-standing and flexible solid polymer electrolyte membranes of PVA-PEG/NaCl modified with g-CDs, a maximum room temperature ionic conductivity of 1.24 × 10−5 S cm−1 is reported which gets enhanced to 1.77 × 10−4 S cm−1 at 60 °C. A high Na ion transference number of 0.43 and a high electrochemical stability window of 0–3.5 V are also observed. Studies on flexible membranes based on PVA-PEG/NaCl/g-CDs as potential candidates in developing solid polymer electrolytes (SPE) have not been reported earlier. Superior Na ion conductivity and Na ion transference number could have originated from the presence of highly dispersed g-CDs with oxygen functional groups that effectively promote the dissociation of NaCl and increase the segmental motion and interconnection between amorphous domains in the blend polymer. [ABSTRACT FROM AUTHOR]

Heterointerfaces introduce unique localized defects into ionic conductors. This study explores the nanoionic characteristics exhibited by the proton-conducting oxides SrZr 0.9 Y 0.1 O 3-δ and SrCe 0.95 Yb 0.05 O 3-δ including finely dispersed precipitated platinum nanoparticles. The electrical conductivity of both the platinum-doped oxides revealed reversible nanoionic phenomena caused by the exsolution of the platinum in the form of platinum nanoparticles, at 0.5 vol% relative to the metal oxides, and dissolution in response to a change in gas atmosphere. In comparison with the original conductivity of SrZr 0.9 Y 0.1 O 3-δ and SrCe 0.95 Yb 0.05 O 3-δ , the conductivity of platinum-doped SrZr 0.9 Y 0.1 O 3-δ decreased significantly in a wet hydrogen atmosphere, whereas platinum-doped SrCe 0.95 Yb 0.05 O 3-δ showed almost no decrease in conductivity in the same atmosphere. The different responses of the two materials to the change in gas atmosphere are discussed in relation to the precipitation of platinum nanoparticles.

La2Ce2O7 is a fluorite‐type oxide, showing almost pure oxide ion conduction in dry oxygen atmosphere. Under wet oxygen atmosphere, protons are introduced into La2Ce2O7 through hydration reaction, making the material proton‐conducting. However, compared with the oxide ion conductivity, the proton conductivity is negligibly small in La2Ce2O7. Here we report the effect of doping trivalent rare earth cations R3+ (R = Y, Ho, Er, Yb, or Tm) and elevating partial pressure of water vapor on the proton concentration and conductivity of La2Ce2O7. The samples show single fluorite phases with the doping level up to 0.2, and the solubilities of these dopants were within 0.2–0.3 in La2Ce2O7. The proton concentration increased by doping, due to higher amount of hydratable oxygen vacancies, and statistical coordination of oxide ions surrounded by R3+ in addition to La3+. The sample with the Y content (x) of 0.05 showed the highest conductivity at 600°C among La2(Ce1−xYx)2O7−δ (x = 0–0.3) samples, possibly due to the balance between the improved hydration ability and decreased mobility of protons with the increasing Y doping level. Then, the dopant content was fixed to 0.05, and La2(Ce0.95R0.05)2O7−δ (R = Y, Ho, Er, Tm, or Yb) was prepared. It was found that as the water vapor partial pressure increased, the proton concentration and conductivity increased regardless of the dopants. Y‐doped La2Ce2O7−δ ha the highest proton concentration and conductivity. [ABSTRACT FROM AUTHOR]

Doped CaZrO 3 oxides exhibit high proton transport number and have been used in electrochemical hydrogen sensor to measure hydrogen content in aluminum melt. Ionic radius of Hf4+ is close to that of Zr4+; thus, it is speculated that doped CaHfO 3 oxides may also possess high proton transport number. In this study, CaHf 1− x In x O 3− δ (x = 0, 0.05, 0.1, 0.15, 0.2, 0.25) perovskite oxides were fabricated via solid-state reaction method. Phase composition and microstructure were characterized by X-ray diffraction and field emission scanning electron microscopy. Conductivities and transport properties of CaHf 1− x In x O 3− δ were investigated via defect equilibria model. The result indicated that conductivities and transport properties of CaHf 1− x In x O 3− δ after In doping could be improved. Moreover, conductivities increased with increasing In doping content until the stoichiometric ratio of Indium element was 0.1. CaHf 0.9 In 0.1 O 2.95 showed the highest total conductivities of 5.58 × 10−8 to 7.04 × 10−3 S ⋅ cm−1 at 400–800 °C. Transport properties showed that CaHf 1− x In x O 3− δ (x = 0.1, 0.15, 0.2, 0.25) oxides were dominated by protonic conduction under 21% O 2 and 2.5% H 2 O atmosphere at 400–650 °C, and the proton transport numbers of CaHf 1− x In x O 3− δ decreased with the increase in temperature in the range of 400–800 °C. CaHf 0.9 In 0.1 O 2.95 (x = 0.1) displayed a maximum proton transport number of 0.50 at 800 °C. These findings show potential application prospects of CaHf 1− x In x O 3− δ in electrochemical hydrogen sensor. [ABSTRACT FROM AUTHOR]

The electrical properties of the proton-conducting electrolyte BaCe 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 3-δ were studied using the 4-probe direct current (DC) method depending on temperature and oxygen partial pressure in the atmospheres, humidified with H 2 O and D 2 O. Ionic and electron hole contributions to the electrical conductivity were determined, and the transport numbers of charge carriers were calculated. It is shown that in air conditions BaCe 0.7 Zr 0.1 Y 0.1 Yb 0.1 O 3-δ is a mixed ion-electron hole conductor. The contribution of electron hole conductivity decreases with the decrease of temperature and oxygen partial pressure. A significant isotope H/D effect in the electrical conductivity is observed for all investigated conditions expressed in the decrease in conductivity in D 2 O-containing atmospheres with the increase of activation energy values. Replacing H 2 O with D 2 O leads to decrease in the ion transport numbers and ionic conductivity values, while the electron hole conductivity remains almost the same. [Display omitted] • Under air conditions BCZYYb is a mixed ion-electron hole conductor. • A significant isotope H/D effect in the electrical conductivity of BCZYYb is observed. • Ionic conductivity of BCZYYb decreases in D 2 O-containing atmospheres. • The kinetic H/D effect dominates under the studied conditions. [ABSTRACT FROM AUTHOR]

KTaO 3 and KTa 0.9 M 0.1 O 3-α (M = Ti, Hf, Zr) were prepared by solid state reaction at 1330 °C for 2 h and characterized by x-ray diffraction. The AC impedance technique was used to analyze the sintered solid electrolytes in 1%H 2 /Ar and dry air atmosphere. Among KTa 0.9 M 0.1 O 3-α (M = Ti, Hf, Zr), KTa 0.9 Zr 0.1 O 3-α displays the highest conductivity in 1%H 2 /Ar atmosphere. The carriers transport numbers of solid electrolytes were measured by concentration cell method. The results show KTa 0.9 Zr 0.1 O 3-α is a pure proton conductor below 525 °C. Stability tests show that KTa 0.9 Zr 0.1 O 3-α has good chemical stability against CO 2 and H 2 O. [ABSTRACT FROM AUTHOR]

ABO3-type perovskite oxides and A3B′B′′2O9-type composite perovskite oxides exhibit proton conduction from 200 ℃ to 1000 ℃. These high-temperature proton conductors have received considerable attention due to their promise as electrolytes in fuel cells, electrolytic hydrogen production, hydrogen separation, electrochemical reactors, sensors, etc. The Ba3Ca1+xNb2−xO9−δ composite perovskite-type solid electrolyte has stable chemical properties and corrosion resistance to CO2 and H2O, so it can be used in long-term electrochemical devices. Protons are incorporated into Ba3Ca1+xNb2−xO9−δ in a humid or hydrogen-containing atmosphere because of the reaction of H2O and oxygen vacancies in proton conductors. However, proton conductors also exhibit oxygen vacancy conduction in the high-temperature range. In addition, electron holes can be generated by an oxygen vacancy reaction with atmospheric oxygen, causing proton conductors to exhibit electron-hole conduction. Hence, more oxygen vacancies can be produced with more Ca2+ dopant in Ba3Ca1+xNb2−xO9−δ due to a lack of positive charge. Meanwhile, the proton and electron-hole concentrations increase with oxygen vacancies, and the conductivity of Ba3Ca1+xNb2−xO9−δ can be improved. However, the crystal structure of Ba3Ca1+xNb2−xO9−δ can be changed with Ca2+ doping, and changes in proton, oxygen vacancy, and electron-hole transport numbers, the ratio of protons, oxygen vacancies, and electron-hole conductivity to total conductivity respectively, are unknown with Ca2+ doping, with different effects of crystal structure for protons, oxygen vacancies, and electron-hole conduction. Ba3Ca1+xNb2−xO9−δ has high conductivity in a humid atmosphere, and the proton transport number with doping amount needs to be further studied. In this work, Ba3Ca1+xNb2−xO9−δ (x=0, 0.10, 0.18, and 0.30) with a composite perovskite phase was prepared using a solid-state reaction method. With the increase in Ca2+ doping amount, the conductivity of Ba3Ca1+xNb2−xO9−δ samples first increased and then decreased, and the conductivity of the sample with x=0.18 was the highest. The electron-hole transport number of Ba3Ca1+xNb2−xO9−δ under the atmosphere containing hydrogen was relatively low. Protons were mainly conductive carriers in Ba3Ca1+xNb2−xO9−δ below 750 ℃, while Ba3Ca1+xNb2−xO9−δ exhibited mainly oxygen vacancy conduction at 800 ℃. With the increase in dopant amount, the oxygen vacancy transport number of Ba3Ca1+xNb2−xO9−δ increased gradually, while the proton transport number decreased gradually.

The structural characteristics, electrical conductivity, counterion transport numbers, and electrokinetic potential of microporous glass subjected to additional heat treatment at 750°С (MIP-750) in 0.1–0.0001 M NaCl solutions have been studied. The results obtained were compared with the properties of micro- and macroporous glasses prepared by the standard methods. It was found that with an increase in the pore size in the series MIP < MIP-750 < MAP, the absolute values of the electrokinetic potential increase. [ABSTRACT FROM AUTHOR]

Understanding the transport phenomena in electrolyte mixtures involved in electrochemical processes is of utmost importance for the modelling and improvement of battery technology, fuel cells, ion-exchange membrane processes, and much more. In this work, we derive relations and present methods for the analysis of electric potential measurements of concentration cells and ion-exchange membrane permselectivity with ternary mixtures of KCl, H 2 O and ethanol (EtOH). Measurements of electric potentials across the Selemion CMVN (cation-exchange) and AMVN (anion-exchange) membranes in this ternary mixture suggest that the presence of EtOH affects the membrane permselectivity, but that the transference of EtOH is zero; i.e. , t a = 0. Instead, the decrease in membrane permselectivity can be explained by a varying water transference coefficient, t w. In the absence of EtOH we find t w ≈ 4 in both membranes, and that the decrease in t w is proportional to the average thermodynamic activity of EtOH in mixtures adjacent to the membranes. The membranes were also found to be charge selective, as quantified by the ionic transport numbers; i.e. , t K + = 1 for the Selemion CMVN and t K + = 0 for the Selemion AMVN. The presented method can readily be extended and leveraged to determine transference coefficients in other electrochemical systems. • New measurements of ion-exchange membrane electric potentials in KCl/H 2 O/EtOH. • Permselectivity is explained via non-eq. thermodyn. and transport numbers. • Permselectivity measurements indicate no transference of EtOH. • The membrane permselectivity varies due to co-transport of water with ions. • The co-transport of water decreases with increased EtOH concentration. [ABSTRACT FROM AUTHOR]

In the aim of developing localized corrosion, artificial corrosion on a steel sheet coated with concrete was implemented through accelerated chloride migration with a constant applied voltage (20 V). Four chloride solutions (20 g/L NaCl) with different initial pH were used. The pH values and chloride concentrations of the solutions were recorded during the test. Electrochemical non-destructive measurements of corrosion potential (Ecorr) and apparent linear polarization resistance (Rp,app) of the steel sheet were made. The concrete cover was then removed to observe corrosion visually (autopsy). The corrosion products were characterized by XRD and SEM and the results showed that the migration of chloride ions in concrete was slowed down by hydroxide ions, which was highlighted by a reduction of chloride transport number. Whether chloride ions were present at the steel interface or not, corrosion occurred because of acidification at the steel sheet/concrete interface due to the anodic polarization. However, when chloride ions were present, the corrosion propagation phase started earlier and the corrosion rate was higher.

• Ion transport is simulated in a membrane electrochemical system towards NH 3 recovery. • NH 4 + dominates ion transport across the cation exchange membrane. • Na+ in anode solution slightly competes with NH 4 + transport. • Na+ in cathode solution benefits NH 4 + transport due to Donnan dialysis. Recovering ammonia nitrogen from wastewater is a sustainable strategy that simultaneously addresses both nitrogen removal and fertilizer production. Membrane electrochemical system (MES), which utilizes electrochemical redox reactions to transport ammonium ions through cation exchange membranes, has been considered as an effective technology for ammonia recovery from wastewater. In this study, we develop a mathematical model to systematically investigate the impact of co-existing ions on the transport of ammonium (NH 4 +) ions in MES. Our analysis elucidates the importance of pH values on both the NH 4 + transport and inert ion (Na+) transport. We further comprehensively assess the system performance by varying the concentration of Na+ in the system. We find that while the inert cation in the initial anode compartment competes with NH 4 + transport, NH 4 + dominates the cation transport in most cases. The transport number of Na+ surpasses NH 4 + only if the fraction of Na+ to total cation is extremely high (>88.5%). Importantly, introducing Na+ ions into the cathode compartment significantly enhances the ammonia transport due to the Donnan dialysis. The analysis of selective ion transport provides valuable insights into optimizing both selectivity and efficiency in ammonia recovery from wastewater. [Display omitted] [ABSTRACT FROM AUTHOR]

Chronopotentiometry and electromotive force methods were used to determine ion transport numbers in two homogeneous and highly selective cation- and anion-exchange membranes. NaCl aqueous solutions of different concentrations, varying from 1 mol·m−3 to 100 mol·m−3 were used to analyze the possible impact of the electrolyte concentration on the results obtained by both methods. Cation transport numbers close to unity for the cation exchange membrane and to zero for the anion-exchange membrane were found for both membrane types with both methods when the NaCl-concentration exceeded 10 mol·m−3. At the lowest concentrations, a systematic deviation from ideal behavior was seen, mainly in the electromotive force method, possibly due to a higher contribution from transport of water. The cation transport number estimated by the electromotive force method was systematically lower than the number obtained from chronopotentiometry, probably due to larger concentration polarization at low electrolyte concentration. We conclude that chronopotentiometry is a relatively rapid and precise technique for ion transport number determination at electrolyte concentrations for which membranes maintain a good selectivity for the measurement conditions used. [ABSTRACT FROM AUTHOR]

[Display omitted] • RE 3 GaO 6 (RE = Nd, Dy, Er) was experimentally verified as a mixed conductor of electron and oxide ion under an O 2 gas flow. • The conductivity of Dy 2.85 Ca 0.15 GaO 6–δ at 973 K was 2.1 × 10–4 S/cm, with the transport numbers of oxide ion being 21 %. • The main migration path of O2– in Dy 2.85 Ca 0.15 GaO 6–δ was via the vacancies at the O2 sites. First-principles calculations were conducted, which proposed that members of the RE 3 GaO 6 (RE = rare earth) system were oxide ion conductors. This study experimentally verified oxide ion conduction in Dy 3 GaO 6 , Er 3 GaO 6 , and Nd 3 GaO 6. The sintered bodies were synthesized by a solid-state reaction method, and their properties were characterized. The samples with dopants were observed to be mixed electron and oxide ion conductors. Dy 2.85 Ca 0.15 GaO 6-δ exhibited oxide ion conductivities of 2.1 × 10−4 S/cm at 973 K, with an oxide ion transport number of 21 % under O 2 gas flow. Additionally, the Rietveld refinement suggested that oxide ion migration might occur via the oxide ion vacancy between the O2 sites. Overall, the oxide ion conductivities of RE 3 GaO 6 increased in the following order: Nd > Dy > Er, which was in good agreement with that predicted by using the first-principles calculations. The discrepancy between the experimentally measured and predicted conductivities was caused by the solid-solution limit at the RE site for the dopants. [ABSTRACT FROM AUTHOR]

Polyvinylidenefluoride (PVDF)-based nanocomposite polymer electrolyte (NCPE) thin films for electrochemical applications have been synthesized by solution cast technique. NCPEs have 70PVDF:30Mg(NO3)2 solid polymer electrolyte (SPE) with conductivity ~7.3 × 10–8 S cm–1 as phase-I and various nanoparticles as phase-II, dispersed in SPE for enhancement in its conductivity. These NCPE films were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and impedance spectroscopic techniques to study the structural and electrical properties. XRD and FTIR studies of film confirms formation of complexes. From composition and temperature dependence of conductivity analysis, we have obtained an optimum conducting composition of NCPE, i.e., 70PVDF:30Mg(NO3)2:3ZnO with conductivity σ = 3.7 × 10–4 S cm–1. Ionic transport number (tion = 0.99) have been calculated from Wagner's dc polarization technique. Electrochemical cell has been fabricated using cell configuration Mg|NCPE|carbon cell and various cell parameters have been calculated from their discharge characteristics. [ABSTRACT FROM AUTHOR]

Nanocomposite anion exchange membranes were prepared using polymeric blend of poly(vinyl chloride) and poly(methylmetacrylate) by solution casting method. Also functionalized carbon nanotubes were used as additive. The carbon nanotube nanoparticles were modified using acid mixtures and ethylenediamine solution and then the structure and morphology of prepared functionalized carbon nanotubes were studied using infrared spectroscopy (FT-IR) and field-emission scanning electron microscopy (FE-SEM). The study of the physicochemical and electrochemical properties of prepared membranes showed that the water content, ion exchange capacity, membrane potential, transport number, surface charge density and permselectivity of them were improved by adding up to2% by weight of carbon nanotubes. Also, the permeability, flux, electrical resistance and chemical stability of prepared membranes with carbon nanotube increased compared to the nanotube-free membranes.In fact, the high active level and the effect of the functionalized carbon nanotube on increasing the hydrophilicity and the transfer properties of the membranes have created suitable ion channels and facilitated ion transport. By adding nanoparticles up to 4% by weight, the electrochemical properties of the prepared membranes were reduced slightly. This can be attributed to the blockade of functional groups by nanoparticles and the accumulation of carbon nanotubes.

In the present research, a novel kind of homogeneous cation-exchange membranes were provided by solution casting technique via blending of sulfonated polyvinylchloride (SPVC) and sulfonated poly phenylene oxide (SPPO). The performance of the membranes was evaluated by membrane potential, areal resistance, transport number, ionic permeability, ion-exchange capacity, fixed ion concentration, energy consumption (EC), current efficiency, mechanical properties, membrane oxidative stability, water contact angle and water content tests. The microstructures of the membranes were investigated by scanning electron microscopy. Membrane with 70:30 (w/w) composition (SPPO: SPVC) exhibited suitable efficiency, mechanical strength and oxidative stability in comparison with other samples in this study. Also, amino groups have been successfully attached to the multi-walled carbon nanotubes (MWCNTs) structure and the modified MWCNTs were selected as filler additive. The results revealed that a series of membranes with improved transport properties, hydrophilicity and EC can be prepared with the polymeric matrix-containing aminated-MWCNTs. [ABSTRACT FROM AUTHOR]

Proton conducting Y‐doped BaZrO3, BaCeO3 and their solid solutions are receiving increasing attention due to their promising application as electrolytes in ceramic fuel cells and electrolysis cells. However, the literature indicates a clear tendency that the performance of the cells increases with increasing Ce content in the electrolyte. In this work, to elucidate this phenomenon, a systematic work is performed on investigating the phase, hydration, and transport behaviors of BaZr0.8−xCexY0.2O3−δ (BZCY20). The results reveal that in the temperature range between 500 and 700 °C, with increasing Ce content, the dehydration temperature elevates and the proton concentration increases, showing that the Ce component favors the stabilization of protons. Furthermore, the transport number of hole conduction decreases, whereas the transport number of ionic conduction increases with the increasing Ce content. By further separating the contribution of oxide ions and protons, it is found that the oxide ion conductivity increases with the increasing Ce content at higher temperatures of 600 and 700 °C. Such decreased hole conductivity and increased oxide ion conductivity result in the enhancement of the ionic conduction of BZCY20 with increasing Ce content, and therefore improve the performance of fuel cells and electrolysis cells. [ABSTRACT FROM AUTHOR]

• Bismuth-based oxides, AE(TM) 2 Bi 2 O 9 , identified by materials informatics, are experimentally verified as good oxide ion conductors (e.g., 3.3 × 10−3 S/cm at 973 K for SrTa 2 Bi 2 O 9 , with transport numbers of >95 %). • First-principles calculations show a microscopic mechanism of the transport properties in terms of the weak bonding of oxygen with Ta or Nb, represented by the charge transfer between Ta/Nb and oxygen. Bismuth-based oxides (AE(TM) 2 Bi 2 O 9 , AE: Ca, Sr, Ba; TM: Nb, Ta), including SrTa 2 Bi 2 O 9 , SrNb 2 Bi 2 O 9 , BaNb 2 Bi 2 O 9 , and CaTa 2 Bi 2 O 9 were synthesized via a conventional solid-state reaction, and their ionic transport properties were investigated. All the materials are verified oxide ion conductors and identified in recent reports using materials informatics. The materials exhibited good oxide ion conductivities, for example, 3.3 × 10−3 S/cm at 973 K for SrTa 2 Bi 2 O 9 with transport numbers > 95 %. The materials have relatively high oxide ion conductivity without doping, which does not increase conductivity. First-principles calculations show a microscopic mechanism of oxide ion transport that is characterized by the weak bonding of oxygen with Ta or Nb. [ABSTRACT FROM AUTHOR]

Poly(ethylene glycol) methyl ether methacrylate polymer networks (PEO-based networks), with or without anionic bis(trifluoromethanesulfonyl)imide (TFSI)-grafted groups, are promising electrolytes for Li-metal all solid-state batteries. Nevertheless, there is a need to enhance our current understanding of the physicochemical characteristics of these polymer networks to meet the mechanical and ionic conductivity property requirements for Li battery electrolyte materials. To address this challenge, our goal is to investigate the impact of the cross-linking density of the PEO-based network and the ethylene oxide/lithium ratio on mechanical properties (such as glass transition temperature and storage modulus) and ionic conductivity. We have synthesized a series of cross-linked PEO-based polymers (si-SPE for single ion solid polymer electrolyte) via solvent-free radical copolymerization. These polymers are synthesized by using commercially available lithium 3-[(trifluoromethane)sulfonamidosulfonyl]propyl methacrylate (LiMTFSI), poly(ethylene glycol)methyl ether methacrylate (PEGM), and [poly(ethylene glycol) dimethacrylate] (PEGDM). In addition, we have synthesized a series of cross-linked PEO-based polymers (SPE for solid polymer electrolyte) using LiTFSI as the ionic species. Most of the resulting polymer films are amorphous, self-standing, flexible, homogeneous, and thermally stable. Interestingly, our research has revealed a correlation between ionic conductivity and mechanical properties in both the SPE and si-SPE series. Ionic conductivity increases as glass transition temperature, α relaxation temperature, and storage modulus decrease, suggesting that Li + transport is influenced by polymer chain flexibility and Li + /EO interaction.

A polyvinyl alcohol supported zirconium tungstate (ZrW/PVA) composite ion exchange membrane has been synthesized by the sol-gel technique. The membrane was prepared by blending zirconium tungstate sol into polyvinyl alcohol gel which was cross-linked with glutaraldehyde (GA). The prepared membrane was analyzed by FT-IR, optical microscopy, SEM, XRD & EDS. The membrane was found to be devoid of any cracks and defects. Electrochemical properties which include transport number, ion exchange capacity (IEC), and proton conductivity were also measured. An IEC count of 0.92 meq.g−1 and transport number of 0.88, thus obtained, were indicators of good electrochemical properties that shows its potential to be used in the direct methanol fuel cell. Moreover, water uptake, methanol uptake and chemical resistivity in the acidic and basic medium of the prepared membrane have also been assessed. Synthesized membrane showed high water holding capacity as compared to Nafion-117. The water uptake of ZrW/PVA composite membrane was found to be 114% which is much higher than that of Nafion-117 (29.2%) 18. The final weight loss of the ZrW/PVA composite membrane in acidic medium was 10%. Oxidative stability of the membrane was evaluated by using Fenton's reagent. The weight loss in the reagent after 24 h was 17% without disruption. • ZrW/PVA composite ion exchange membrane was successfully developed. • An IEC count of 0.92 meq.g−1 and a transport number of 0.88 was obtained. • The water uptake of ZrW/PVA composite membrane was found to be 114%. • Final weight loss in acidic medium was 10% & in the basic medium was 26%. • Oxidative stability under Fenton's reagent revealed 17% loss in weight. [ABSTRACT FROM AUTHOR]

In this study, ion exchange nanocomposite membranes was prepared by addition of Mg(OH)2 nanoparticles to a blend containing sulfonated polyphenylene oxide and sulfonated polyvinylchloride via a simple casting method. Magnesium hydroxide nanoparticles were synthesized via a facile sono-chemical reaction and were selected as filler additive in fabrication of ion exchange nanocomposite membranes. Nanoparticles and nanocomposites were then characterized using scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. The effect of nanoparticles loading on physicochemical and electrochemical properties of prepared cation exchange nanocomposite membranes was studied. The membranes performance was evaluated by membrane potential, transport number, permselectivity, ionic permeability, flux of ions and membrane oxidative stability. Various characterizations revealed that the addition of different amounts of inorganic fillers could affect the membrane performance. The inorganic nanoparticles not only created extra pores and water channels that led to ion conductivity enhancement, but also improved transport number, permselectivity and flux of ions.

SrCe 0.9 Y 0.1 O 3-δ -Ce 0.9 Y 0.1 O 2-δ (SCY-YDC, 1:1 mole ratio), as a novel composite electrolyte, was successfully synthesized and characterized. X-ray diffraction patterns showed that SCY-YDC composite electrolyte is a mixture of SCY and YDC. Besides, no impurity phase emerged after sintering at 1550 °C for 10 h. AC impedance spectroscopy was used to determine the electrical properties of SCY-YDC at 500–800 °C in various atmospheres. Partial conductivities of oxygen vacancies, protons, and electrons (p-type) were calculated using the defect structure model. Results showed that SCY-YDC is a mixed (hole, proton, and oxygen-ion) conductor. Moreover, the contribution of holes is minor at 650–800 °C in high pressure (1 atm) or low pressure (10−4 atm) O 2 atmospheres. Dominant carrier switched from protons to oxygen ions as temperature increased at vapor pressure in air of 0.038 atm. Total conductivity for SCY-YDC is 6.19 × 10−3 S cm−1 at 800 °C under pO 2 = 1 atm and pH 2 O = 6 × 10−3 atm, which is higher than that of SCY (2.47 × 10−3 S cm−1). Results also showed that SCY-YDC composite material exhibits higher ionic conductivity and lower electron-hole conductivity than SCY. Electron-hole transference number for SCY-YDC is 0.049 at 800 °C in pO 2 = 0.21 atm and pH 2 O = 0.038 atm. Ultraviolet–visible spectrophotometry results provided evidence that SCY-YDC can suppress electron conduction. [ABSTRACT FROM AUTHOR]

Solid and liquid electrolytes for electrochemical energy storage and conversion cells, such as batteries, supercapacitors and fuel cells, contain often high concentrations of mobile ions. Therefore, the ion dynamics in these electrolytes is characterized by pronounced directional correlations between successive ion movements, which exert a strong influence on charge and mass transport. In this manuscript, we review the relevant transport properties of (i) single‐ion conducting solid electrolytes and of (ii) liquid electrolytes with a single type of cations and a single type of anions. All transport quantities are based on Onsager's linear irreversible thermodynamics and are defined in the laboratory frame of reference, so that they can be easily related to correlations functions of the equilibrium ion dynamics by means of linear response theory. In the case of single‐cation conducting solid electrolytes, we discuss how the complex interplay between cation‐cation and cation‐lattice interactions leads to a competition between cation self‐correlations and distinct‐cation correlations. In the case of liquid electrolytes, we describe how cation‐cation, anion‐anion, and cation‐anions correlations influence the various transport quantities, such as total ionic conductivity, Haven ratio, salt diffusion coefficient and cation transference numbers. Moreover, we discuss how, in dilute liquid electrolytes, ion correlations can be governed by ion pair formation. Finally, the competition between cation/anion and cation/polymer chain interactions can lead to negative cation transference numbers in polymer electrolytes, i. e. to cations migrating towards the positive electrode. Taken together, these case studies showcase how ion correlations in electrolyte systems can strongly influence the overall efficiency of energy storage and conversion devices due to transport limitations. [ABSTRACT FROM AUTHOR]

Proton conductive BaZr0.8Y0.2O3−δ (BZY20) is a promising electrolyte candidate with perspective application in electrochemical devices, including fuel cells, electrolyzer cells. Mn, Fe, and Co are commonly incorporated into BZY20, to improve the sinterability (CoO), or due to possible inter‐diffusion by calcining with cathode materials (eg, La1−xSrxMnO3−δ, La1−xSrxCo1−yFeyO3−δ) for cell preparation. This work was performed to investigate the influence of Mn, Fe, and Co on the structural and electrochemical properties of BZY20. As reported in literature, the sinterability of BZY20 was improved by adding CoO. XANES analysis shows that Mn, Fe, and Co are possibly incorporated into the perovskite crystal structure of BZY20, and are partially reduced when the samples were exposed to hydrogen at 600°C for 24 hours. However, through electrochemical analysis, we found that all these three elements decrease both the proton conductivity and transport numbers of proton conduction of BZY20. Therefore, the BZY20 electrolyte should be carefully handled to avoid the incorporation of these transition metal elements, to fabricate the cells with high performance. [ABSTRACT FROM AUTHOR]

We analyse electromotive force measurements of concentration cells using non-equilibrium thermodynamics, and determine the transference coefficients of ion-exchange membranes in aqueous KCl solutions. By taking advantage of the analytical expression for the permselectivity, we extract transport coefficients with high accuracy. The transport number of K+ and the transference coefficient of water in the Selemion CMVN cation-exchange membrane are found to be 100 t K + = 99. 59 ± 0. 56 and t w = 3. 69 ± 0. 40 respectively, while for the Selemion AMVN anion-exchange membrane they are 100 t Cl − = 100. 21 ± 0. 37 and t w = − 3. 75 ± 0. 27. These results suggest that the membranes are perfectly selective to the target ion, and that each ion carries 3-4 water molecules through the membrane, which reduces the membrane permselectivity. In these concentration cells, the electrical potential contribution of the membrane alone was more easily isolated with bare Ag/AgCl electrodes without reference solutions and liquid junction plugs. Additionally, we find a large contribution to the measured concentration cell voltage from concentration gradients across the porous plug of the reference electrode, which cannot be explained by Henderson's equation alone. For most of the concentration range, the transport number of the porous plug is determined to be 100 t K + = 49. 43 ± 0. 78 with negligible water transport, similar to literature values for bulk electrolyte. In dilute electrolyte solutions with concentrations below 0.1 mol kg−1, the plug shows anomalous behaviour consistent with an increase in K+ selectivity and water co-transport. [Display omitted] • Membrane potentials of Selemion CMVN and AMVN in KCl solutions were measured. • Permselectivity modelled as function of salt and water transference numbers. • Permselectivity varies due to the co-transport of water with ions. • Water co-transport reduces available work from a reverse electrodialysis cell. • Junctions of reference electrodes have large contributions to measured voltages. [ABSTRACT FROM AUTHOR]

Membrane resistance and permselectivity for counter-ions have important roles in determining the performance of cation-exchange membranes (CEMs). In this study, PVA-based polyanions—poly(vinyl alcohol-b-sodium styrene sulfonate)—were synthesized, changing the molar percentages CCEG of the cation-exchange groups with respect to the vinyl alcohol groups. From the block copolymer, poly(vinyl alcohol) (PVA)-based CEMs, hereafter called “B-CEMs”, were prepared by crosslinking the PVA chains with glutaraldehyde (GA) solution at various GA concentrations CGA. The ionic transport properties of the B-CEMs were compared with those previously reported for the CEMs prepared using a random copolymer—poly(vinyl alcohol-co-2-acrylamido-2-methylpropane sulfonic acid)—hereafter called ”R-CEMs”. The B-CEMs had lower water content than the R-CEMs at equal molar percentages of the cation-exchange groups. The charge density of the B-CEMs increased as CCEG increased, and reached a maximum value, which increased with increasing CGA. A maximum charge density of 1.47 mol/dm3 was obtained for a B-CEM with CCEG = 2.9 mol% and CGA = 0.10 vol.%, indicating that the B-CEM had almost two-thirds of the permselectivity of a commercial CEM (CMX: ASTOM Corp. Japan). The dynamic transport number and membrane resistance of a B-CEM with CCEG = 8.3 mol% and CGA = 0.10 vol.% were 0.99 and 1.6 Ωcm2, respectively. The B-CEM showed higher dynamic transport numbers than those of the R-CEMs with similar membrane resistances.

The transport properties of various anion and cation exchange membranes were studied in different electrolyte solutions using chronopotentiometry technique to get insight about the influence of the counter ion on the transport properties of the membranes. The investigated samples include heterogeneous ion exchange membranes varying in the functionality of fixed charged groups, physical properties of the polymer and the preparation procedure. Chloride and nitrate were investigated as counter-ion in their sodium salts for anion exchange membranes while sodium, calcium, potassium, and magnesium were selected as counter-ion in their chloride salts to study cation exchange membranes transport properties. First, the current – voltage curve of an ion exchange membrane in a given solution was recorded to obtain the limiting current, then a constant current above the limiting current was used for chronopotentiometry measurement. In all the studied membranes the potential across the membrane remained constant for a time interval called the transition time , when a constant current was applied. Then the potential increased rapidly to reach the steady state potential. The permselectivty and the transport number of a membrane were calculated using the corresponding transition time.

An analytical method to determine the electrochemical energy efficiencies of electrolytes with partial electronic conduction has been developed previously and reported in the literature. However, this analytical method does not address the effects of differing ionic species in electrolytes, i.e., the oxide‐ions or protons. Therefore, we aimed to modify this analytical method to account for the effects of differing ionic species, and applied it to compare the energy efficiencies of oxide‐ion conducting solid electrolytes such as yttria‐stabilized zirconia (YSZ) and gadolinia‐doped ceria (GDC) to proton‐conducting solid electrolytes, such as yttria‐doped barium zirconate (BZY). With the modification, difference in the influence of the fuel consumption between the oxide‐ion conducting electrolyte and the proton‐conducting electrolyte has been successfully taken into account. The energy efficiency of the BZY electrolyte relatively increased against those of YSZ or GDC electrolytes by the modification. Additionally, partial oxide‐ion conduction in the proton‐conducting electrolyte was successfully estimated using the modified analytical method. [ABSTRACT FROM AUTHOR]

A series of Ba 3 Sr 1+ x Ta 2− x O 9− δ (x = 0,0.1,0.2,0.3,0.4) double perovskite proton conductors were fabricated at 1400 °C for 10 h and further sintered at 1650 °C for 10 h via a solid-state reaction process. Their phase composition, microstructure characterization and valence were investigated by XRD, FESEM and XPS techniques. Conductivities of these proton conductors were measured under the atmosphere of various water vapor and oxygen pressures by the electrochemical impedance spectra technique. It was found that the grain boundary thicknesses of Ba 3 Sr 1+ x Ta 2− x O 9− δ were significantly higher than other perovskite proton conductors. The total conductivities of Ba 3 Sr 1+ x Ta 2− x O 9− δ increased with the increase of both temperature and stoichiometric proportion of Sr, and Ba 3 Sr 1.4 Ta 1.6 O 8.4 exhibited the highest conductivity of about 4.4 × 10−3 S cm−1 at 750 °C. Additionally, the transport numbers of proton, oxide ion and hole were measured using defect equilibria model. The results indicated that Ba 3 Sr 1+ x Ta 2− x O 9− δ oxides were almost pure proton conductors at 400–550 °C and mixed proton - oxide ion - hole conductors at 550–850 °C, and Ba 3 Sr 1.3 Ta 1.7 O 8.55 exhibited the highest protonic transport number. The performance of the hydrogen sensor using Ba 3 Sr 1.3 Ta 1.7 O 8.55 was also measured in various hydrogen partial pressure, a good linear relationship between EMF and p H 2 was observed at 400–800 °C, and the response time was around 10s. • The structure of Ba 3 Sr 1+ x Ta 2− x O 9− δ moved from P 6 3 / mmc into F m 3 ¯ m with increasing x. • Ba 3 Sr 1.4 Ta 1.6 O 8.4 displayed a higher conductivity than BCN18. • The protonic transport number of Ba 3 Sr 1.3 Ta 1.7 O 8.55 is 0.88 at 600 °C. • The hydrogen partial pressure can be measured accurately at 400–800 °C. [ABSTRACT FROM AUTHOR]

Abstract In this study, the NiO additive was employed as a sintering aid to prepare dense BaZr 0.9 Y 0.1 O 3-δ (BZY10) ceramics for proton ceramic fuel cell (PCFC) and electrolysis cell (PCEC) applications. It was found that the NiO additive contributed to facilitating the grain growth and enhancing the proton conductivity of BZY10 ceramics. However, the subsequent studies on the transport number reveal a detrimental effect of NiO additive on increasing the electronic leakage of BZY10 ceramics under humid oxidizing atmosphere. This is expected to cause the misdiagnosis of the electrocatalytic activity of PCFC cathodes and a lower Faraday efficiency of PCECs. Considering the utilization of BZY10 ceramics as the proton conducting electrolyte, it is preferred to obtain a high density (∼95%) and applicable proton conductivity at the minimum NiO usage. This strategy was achieved by sintering the nanocrystalline BZY10 powders with 0.2 wt% NiO additive at 1500 °C for 6 h in air, of which the usage is 80% lower than that in the well-known solid state reactive sintering approach. Highlights • 0.2 wt% NiO additive facilitates densification of BZY10 proton conducting ceramics. • Compared to BZY10 ceramic, 0.2 wt%NiO addition induces even grain size distribution. • BZY10 + 0.2 wt%NiO ceramics give a proton conductivity of 0.0024 S cm−1 at 400 °C in H 2 • 0.2 wt% NiO addition increases electronic leakage of BZY10 in oxidizing atmosphere. [ABSTRACT FROM AUTHOR]

Abstract A detailed analysis of the electrical properties of the proton-conducting BaCe 0.8 Y 0.2 O 3-δ phase (BCY20) and the effects of Br doping has been undertaken. Members of the system of nominal stoichiometry BaCe 0.8 Y 0.2 O 2.9-(x/2)±δ Br x (x = 0, 0.05, 0.1 and 0.2) were synthesised by a citrate-nitrate process and high-temperature annealing up to 1500 °C. X-ray diffraction revealed the formation of single-phase material with a monoclinically distorted perovskite structure (space group I2/m) with greater distortion for Br-synthesised phase. Significant contrasts in electrical behaviour and stability between BCY20 and Br-synthesised series members were also found. However, chemical analysis by total X-ray fluorescence spectroscopy indicated that only trace amounts of Br remain after synthesis, indicating that Br addition influences stoichiometry but not directly the physicochemical properties. Higher conductivity is observed for the Br-synthesised compositions in wet and dry oxidising conditions in the temperature range 300–900 °C, reaching a value of 5.8 S m−1 at 800 °C for the x = 0.2 member in wet O 2 (pH 2 O ∼ 0.022 atm). Determination of partial-conductivity components indicated that, in humid conditions and low temperature, the conductivity of 20% Br-synthesised material is principally protonic (t H = 0.91 at 600 °C and pO 2 = 0.2 atm) and superior to that of BCY20. Mixed oxide-ionic-electronic conductivity dominates at high pO 2 (1 atm) and oxide-ionic conductivity at low pO 2 (∼10−4 atm) in the temperature range 600–900 °C for both BCY and Br-doped samples. Stability was found to be poorer in CO 2 for the Br-synthesised phases as determined by thermogravimetry and prolonged conductivity measurements. Graphical abstract Br addition on synthesis of BCY samples improves the ionic transport numbers in both wet and dry conditions. Image 1 [ABSTRACT FROM AUTHOR]

An electrolyte in fuel cells requires not only high ionic conductivity, but also high transport numbers of ionic conduction. Although Y‐doped BaZrO3 is regarded to be the most promising candidate as the electrolyte in protonic ceramic fuel cells (PCFCs), significant hole conduction generates in wet oxygen at high temperatures. With the aim to increase the transport number of ionic conduction, in this work, Sr and Ca were introduced to partially substitute Ba in BaZr0.8Y0.2O3‐δ. The results revealed that a single cubic perovskite phase was obtained for Ba0.95Ca0.05Zr0.8Y0.2O3‐δ and Ba1‐xSrxZr0.8Y0.2O3‐δ (x = 0.05, 0.10, 0.15, 0.20 or 0.40). However, replacing Ba with Sr resulted in almost no increase in the transport number of ionic conduction in wet oxygen atmosphere, but drastic decrease in proton conductivity at all replacement levels. In addition, Ba0.95Ca0.05Zr0.8Y0.2O3‐δ shows no meaningful change in the transport number of ionic conduction, compared with BaZr0.8Y0.2O3‐δ. Incorporating Ca or Sr into the Ba‐site of BaZr0.8Y0.2O3‐δ appears to impart no positive influence on electrochemical properties. These interesting results also indicate that the hole conductivity decreases with the decrease in proton conductivity, and will aid to consider the hole conduction mechanism. BaHfO3 doped with 10 and 20 mol% Y was also prepared. A bimodal microstructure was observed for BaHf0.9Y0.1O3‐δ, whereas BaHf0.8Y0.2O3‐δ shows uniform grain size after sintering at 1600°C for 24 hours. The transport numbers of ionic conduction and bulk conductivity in such Y‐doped BaHfO3 samples are close to those of BaZrO3 doped with the same amount of Y. [ABSTRACT FROM AUTHOR]

An electrolyte in fuel cells requires not only high ionic conductivity, but also high transport numbers of ionic conduction. Although Y‐doped BaZrO3 is regarded to be the most promising candidate as the electrolyte in protonic ceramic fuel cells (PCFCs), significant hole conduction generates in wet oxygen at high temperatures. With the aim to increase the transport number of ionic conduction, in this work, Sr and Ca were introduced to partially substitute Ba in BaZr0.8Y0.2O3‐δ. The results revealed that a single cubic perovskite phase was obtained for Ba0.95Ca0.05Zr0.8Y0.2O3‐δ and Ba1‐xSrxZr0.8Y0.2O3‐δ (x = 0.05, 0.10, 0.15, 0.20 or 0.40). However, replacing Ba with Sr resulted in almost no increase in the transport number of ionic conduction in wet oxygen atmosphere, but drastic decrease in proton conductivity at all replacement levels. In addition, Ba0.95Ca0.05Zr0.8Y0.2O3‐δ shows no meaningful change in the transport number of ionic conduction, compared with BaZr0.8Y0.2O3‐δ. Incorporating Ca or Sr into the Ba‐site of BaZr0.8Y0.2O3‐δ appears to impart no positive influence on electrochemical properties. These interesting results also indicate that the hole conductivity decreases with the decrease in proton conductivity, and will aid to consider the hole conduction mechanism. BaHfO3 doped with 10 and 20 mol% Y was also prepared. A bimodal microstructure was observed for BaHf0.9Y0.1O3‐δ, whereas BaHf0.8Y0.2O3‐δ shows uniform grain size after sintering at 1600°C for 24 hours. The transport numbers of ionic conduction and bulk conductivity in such Y‐doped BaHfO3 samples are close to those of BaZrO3 doped with the same amount of Y. [ABSTRACT FROM AUTHOR]

Fast ion-conducting (FIC) system composed of xCdI2-(100-x)[44.4Ag2SO4-55.6(40TeO2-60B2O3)] has been prepared by melt-quenching method. The prepared samples were characterized by X-ray diffraction (XRD), impedance, and transport studies. XRD, DSC studies conclude that the samples with x = 0 to 20 show predominantly glassy nature. Conductivity measurements were performed in the frequency range 20 Hz-3 MHz by varying temperature from 30 to 150 °C. Electrical parameters such as conductivity and activation energies of all the samples were evaluated by complex impedance analysis and Arrhenius plots, respectively. The obtained results of conductivity are discussed using exchange reaction between the cations based on Lewis’ hard and soft acids and bases (HSAB) principle. Ionic conductivity is identified as being mainly due to Ag+ ions. The highest conductivity (order of 10−4 S cm−1) and ionic current (2.063 μA) is observed for CBT20 sample at room temperature; hence, it can be used as the best electrolyte material for solid-state battery application. [ABSTRACT FROM AUTHOR]

Silver ion conducting glass system composed of xAgI-(100 − x)[0.444 Ag2SO4-0.555 (0.4TeO2-0.6B2O3)] has been prepared by melt quenching method for x = 0 to 80 in step of 10. XRD, DSC, FTIR, and SEM were carried out to understand some structural properties of prepared samples. XRD and DSC studies of the samples with x ≤ 60 show predominantly glassy nature. Electrical parameters and activation energies of all the samples were evaluated by complex impedance analysis and Arrhenius plots of DC conductivity, respectively. Carrier concentration, mobility, inter-ionic distance, and ionic conductivity of samples were measured and discussed. It is observed that the conductivity varies with increasing the temperature and composition. The highest conductivity (1.8 × 10−1 S cm−1) and ionic current (8.33 μA) is observed for = 50 sample at room temperature; hence, it can be used as best electrolyte material for solid-state battery application. [ABSTRACT FROM AUTHOR]

An ion exchange membrane is a polymer matrix of cross-linked polyvinyl chloride macromolecular chains, on which are grafted ionic functional sites. The transport numbers of two metal ions and proton through these membranes were determined using the well-known electrochemical Hittorf’s method. The cation exchange membrane Nafion, having sulfonic reactional site (-SO3−), yielded the transport number of copper relatively less than that of sodium, leaving way to proton to be transported. In contrast, the anion membrane of alkyl ammonium reactional site (-NR4+) prevented the transfer of cation metals and allowed the proton to displace by defect of permselectivity. These two membranes were used as separators in microbial fuel cells (MFC). In effect, the MFC with the anion membrane AMX, gave relatively higher power density (1.10 mW/m2) compared to the cation exchange membrane Nafion (0.45 mW/m2). Really, with the AMX separator, the metal ions present in the wastewater anolyte compartment were blocked by the membrane giving way to the protons to displace freely and be reduced efficiently at the cathode. In the mono-compartment cell, the ions moved sideways between anode and cathode, yielding the highest power density (11.90 mW/m2) so far obtained. The pH adjustment of anolyte and cathode compartments support, therefore, strongly the cell voltage evolutions. In addition, the cyclic voltammetry results showed that the electroactive biofilm of the bioanode using the AMX membrane described a diffusion-limited process, while that of the Nafion membrane made in evidence the adsorption monolayer of redox species. Besides, the electrochemical impedance spectroscopy revealed that the charge transfer resistance at the interface bioanode/biofilm decreased drastically from 728 to 18 Ω cm2 for Nafion MFC during 11 days of functioning. [ABSTRACT FROM AUTHOR]