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Enhancing the electronic and ionic conductivity of Li 4 Ti 5 O 12 electrode materials, as well as suppressing the interface reaction between Ti4+ on the surface of Li 4 Ti 5 O 12 and the electrolyte, is one of the key factors in preparing high-power and long-life Li 4 Ti 5 O 12 lithium-ion batteries. To tackle these challenges, fluorine ions with strong electronegativity was chosen as dopants to engineer fluorine-doped Li 4 Ti 5 O 12 electrode materials. Fluorine ion doping changes the surface state of Li 4 Ti 5 O 12 , increases the interface compatibility, suppresses the reactivity between Li 4 Ti 5 O 12 and the electrolyte, and forms a uniform SEI film during cycling. Moreover, fluorine ion doping induces the generation of oxygen vacancies and improves the crystallinity of Li 4 Ti 5 O 12 , thereby fostering improved electronic and ionic transport kinetics. The above appealing features enables the prepared fluorine-doped Li 4 Ti 5 O 12 material demonstrates exceptional high-rate performance, delivering specific capacities of 175 mAh·g−1/0.5C, 159 mAh·g−1/10C, and 138 mAh·g−1/50C. In essence, the fluoride ion doping strategy holds profound implications for enhancing electrode interface characteristics, transport kinetics, and the fabrication of high-power lithium-ion batteries. [ABSTRACT FROM AUTHOR]

The non-stoichiometric Bi 4 (V 0.9 Cu 0.1) x O 6+2.35 x (nx-BICUVOX) samples were designed and synthesized by solid-state reactions. The tetragonal γ -Bi 4 (V 0.9 Cu 0.1) x O 6+2.35 x solid solution is identified as 1.80 ≤ x ≤ 2.05 by X-ray diffraction (XRD) analysis. The unit cell of nx-BICUVOX shows an anisotropic in-plane layer shrinkage and the cell volume V decreases from 240.18(2) Å3 to 237.99(1) Å3 as x increases from 1.80 to 2.05. The nx-BICUVOX shows a large positive thermal expansion with the volume thermal expansion coefficient (TEC) estimated to be 5.20 × 10−5 K−1, 5.48 × 10−5 K−1, 5.90 × 10−5 K−1 from RT to 700 °C, for Bi 4 (V 0.9 Cu 0.1) 1.80 O 10.23 , Bi 4 (V 0.9 Cu 0.1) 1.90 O 10.465 , Bi 4 (V 0.9 Cu 0.1) 2.00 O 10.7 , respectively. The nx-BICUVOX shows an obvious electronic insulating manner. Three peaks of V-2 p , three peaks of O-1 s and two peaks of Bi-4 f are observed in X-ray photo-electron spectroscopy (XPS) of nx-BICUVOX, which agrees with the crystal structure of the nx-BICUVOX. The grain conductivity of nx-BICUVOX (x ≠ 2.00) is significantly higher than that of stoichiometric Bi 4 (V 0.9 Cu 0.1) 2.00 O 10.7. The Bi 4 (V 0.9 Cu 0.1) 1.95 O 10.5825 and Bi 4 (V 0.9 Cu 0.1) 2.05 O 10.8175 show the highest grain conductivity, in which accompanying with the smallest activation energy. Therefore, the composition control of nx-BIMEVOX is an effective way in the research and development of new BIMEVOX electrolytes. [ABSTRACT FROM AUTHOR]

Solid-state electrolyte structures using sodium polyaluminate ceramics, have been fabricated for the first time using direct ink writing; a material extrusion-based additive manufacturing process. A series of test samples were prepared using a high solids loading (80 wt%; 51.2 vol%) ceramic paste formulations with suitable rheological characteristics for 3D printing. Following optimum densification via conventional sintering at 1600 °C for 30 min, the additively manufactured electrolyte test samples exhibited an ionic conductivity of σ = 0.14 ± 0.019 S·cm−1 at 300 °C and density of ρ = 3.1 ± 0.02 g·cm−3 (relative density of 95%). These results suggest that direct ink writing of sodium polyaluminates is a promising approach for electrolyte manufacture. Additionally, this approach shows great potential for manufacturing complete solid-state battery structures, through multi-material direct ink writing. [ABSTRACT FROM AUTHOR]

An innovative sintering technique, the Cold Sintering Process (CSP), has been employed to obtain dense Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) Solid-State Electrolytes (SSE) by optimising the particle size (d 50) of the starting powder. The CSP is carried out at 700 MPa, 150 ºC, and 90 min of sintering time, using acetic acid solution as Transient Liquid Phase (TLP). The CSP lowers the LATP sintering temperatures almost 1000 ºC. To study the electrical properties, an in operando Electrochemical Impedance Spectroscopy (EIS) technique has been used. The optimum d 50 is 0.415 µm, yielding to competitive microstructure and electrical properties (ionic conductivity of 6.93·10−5 S cm−1 at 30 ºC, activation energy of 0.363 eV, and a relative density of 81.2 ± 0.8%). Relative density, ionic conductivity and TLP content must be balanced, because at small d 50 , although relative density is enhanced the ionic conductivity is reduced. A packing model has been used to understand this behaviour and the mass transfer mechanisms. [Display omitted] • Cold Sintering Process method to sinter LATP Solid Electrolyte. • Combination of 3 cornerstones: particle size, CSP and in operando impedance. • Effect of particle size on microstructure and electrical properties. • Dissolution-precipitation mechanisms involving the Cold Sintering Process. [ABSTRACT FROM AUTHOR]

Solid-state electrolytes (SSEs) play a crucial role in solid-state lithium metal batteries, with covalent organic frameworks (COFs) emerging as a promising materials class for SSE applications. In this study, a series of Tp-COFs materials were successfully synthesized through a solvothermal approach. Subsequently, these COFs underwent a coating process involving lithium salt and polyvinylidene fluoride film to yield TpMa, TpDa, and TpDa-Li SSEs. The materials subjected to characterization for their ionic conductivity, Li+ transfer number, electrochemical window, and charge-discharge cycle performance. Particularly noteworthy was the exceptional performance of TpDa-Li, exhibiting an ionic conductivity of 9.25 × 10−4 S cm−1, a Li+ transfer number of 0.89, an electrochemical window spanning 1.0–4.4 V, and a capacity retention rate of 77% after 300 cycles at 1 C rate and 83% after 300 cycles at 0.2 C rate. • TpMa, TpDa, and TpDa-Li COFs compounds were successfully synthesized through a solvothermal method. • TpPa-Li was applied to all-solid-state lithium metal batteries. • TpDa-Li solid electrolyte shows a high ionic conductivity of 9.25 × 10−4 S cm−1, a Li+ transfer number of 0.89. [ABSTRACT FROM AUTHOR]

Amorphous Li 3 PS 4 , Li 2.94 Mn 0.06/n PS 4 (M = Mg, Ca, Al) and Li 2.94 Ca 0.03 PS 3.94 Xy 0.06/y (X = N, I) solid electrolytes were successfully prepared by planetary ball-milling method. Their structure was investigated using XRD and Raman spectroscopy. The data obtained from complex impedance spectroscopy was analyzed to study the ionic conductivity and relaxation dynamics in the prepared samples. The data was interpreted using conductivity isotherms, electrical modulus and dielectric loss tangent. Among the samples, Li 2.94 Al 0.02 PS 4 exhibited highest ionic conductivity at 25 °C, which was about 6.6 x 10−4 Scm−1. Electrical modulus and dielectric loss tangent analysis suggested that grain boundary polarization and ionic conductivity increased with multivalence cation doping. [ABSTRACT FROM AUTHOR]

The commercial potential of composite polymer electrolytes (CPEs) is significant due to their ability to combine the advantages of both inorganic and polymer solid electrolytes. However, the unstable interface and insufficient ionic conductivity remain important challenges in practical applications of CPEs for achieving high-performance solid-state lithium batteries (SLBs). Herein, we construct a double-layer composite polymer electrolyte (D-CPE) by incorporating nanosized TiO 2 fillers with adjustable concentrations of oxygen vacancies into poly (ethylene oxide) (PEO)-based electrolyte composites. In the D-CPE structure, one CPE layer containing TiO 2 fillers with oxygen vacancies exclusively interfaces with the LiFePO 4 cathode, while the other CPE layer consisting of pristine TiO 2 fillers (with negatively charged surfaces) solely contacts the lithium anode. This design of D-CPE achieves high ionic conductivity, a broad electrochemical window, and interfacial stability without additional resistance at the electrolyte-electrolyte interface simultaneously. The LiFePO 4 /D-CPEs/Li battery exhibits excellent cycling stability at 0.1 C, maintaining a capacity of 157.2 mAh g−1 with a capacity retention rate of 99.1% after 100 cycles. Furthermore, even at 0 °C, it delivers an impressive discharge capacity of 133.1 mAh g−1 at 0.1 C. This work presents a simple and effective approach to achieving superior polymer-based electrolytes for high-performance solid-state lithium batteries. [ABSTRACT FROM AUTHOR]

In this paper, the effects of frequency on the flash sintering behavior and microstructure of Li 6.4 Ga 0.2 La 3 Zr 2 O 12 (0.2Ga-LLZO) were investigated. The results showed that an increase in frequency had little effect on the onset temperature, but this increase reduced the duration of the weak current stage the incubation stage. Moreover, this phenomenon led to a decrease in the power loss during the constant current stage. Scanning Electron Microscope images showed that the microstructure was symmetrically distributed, and the uniformity increased with increasing frequency. Finite element simulations and an IR thermocamera were used to analyze the temperatures of the specimens. The symmetric distribution of temperature during the flash sintering process was the root cause. The results of AC impedance spectroscopy showed that when the frequency of flash sintering was ≥ 400 Hz, the ionic conductivity of Ga-LLZO was greater than that of conventional sintering. The results of this work demonstrated the important role of frequency in controlling the microstructures of ceramic materials in flash sintering. [ABSTRACT FROM AUTHOR]

Proton exchange membranes (PEMs) are the core components of fuel cells, and research has long focused on how to balance their proton conductivity and durability. In this work, a series of homogeneous blend of sulfonated polyimide (SPI) and sulfonated polyether ether ketone (SPEEK) hybrid membranes with were constructed refined with sulfonated MoS 2 (H–MoS 2) and sodium lignosulfonate (SLS). The results showed that the tensile strength of the films was enhanced by 39.4% (67.84 MPa) compared to the base film. The composite films incorporating 1 wt% H-MoS 2 and 2 wt% SLS has excellent proton conductivity, which can reach 50.24 mS/cm at 80°C and 100% humidity. The embed hybrid structure constructed by H–MoS 2 and SLS, which not only effectively solves the limitations of the proton transport channel of traditional polymer materials, but also provides abundant proton transport sites, which provides a new strategy for preparing high-performance PEM. [Display omitted] • The stability of composite films was improved by organic/inorganic co-modification • H–MoS 2 and SLS together construct a continuous proton transport channel • The tensile strength of the best composite film is up to 67.84 MPa [ABSTRACT FROM AUTHOR]

Symmetrical solid oxide fuel cell (S–SOFC) has gained extensive attention for its simplifying fabrication process and reducing cost. Fe-based double perovskite PrBaFe 2 O 5+δ (PBF) is a potential electrode material for S–SOFC due to the excellent mixed electronic and oxygen ionic conductivity. However, the electrochemical performance of PBF is limited by lacking enough oxygen vacancies and the sluggish oxygen-ion transport kinetics. Herein, a BaCoO 3-δ (BCO) impregnated PBF (PBF–BCO) electrode is investigated with enhanced catalytic activity. The BCO decoration can significantly decrease the polarization resistance (Rp) by approximately 36.5% and 26.0% compared to PBF at 800 °C in air and hydrogen atmosphere, respectively. The peak power density (PPD) of an electrolyte-supported S–SOFC with PBF–BCO electrode is nearly 36% higher than that of PBF electrode. The prominent electrochemical performance of the PBF–BCO electrode is attributed to the significantly accelerated oxygen adsorption/dissociation processes, which promote the oxygen reduction reactions (ORR) and enhanced charge transfer processes in H 2 atmosphere for superior hydrogen oxidation reaction (HOR). The results demonstrate that the BCO impregnated PBF is one of the promising electrode materials for S–SOFC. • BCO impregnated PBF are studied as electrodes for S–SOFC. • The introduction of BCO can reduce the Rp of PBF in air and hydrogen atmospheres. • The PBF–25BCO electrode achieves a 36% enhancement in PPD compared with the PBF. • PBF–25BCO cell displays favorable stability under operating conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] Traditional dual-ion lithium salts have been widely used in solid polymer lithium-metal batteries (LMBs). Nevertheless, concentration polarization caused by uncontrolled migration of free anions has severely caused the growth of lithium dendrites. Although single-ion conductor polymers (SICP) have been developed to reduce concentration polarization, the poor ionic conductivity caused by low carrier concentration limits their application. Herein, a dual-salt quasi-solid polymer electrolyte (QSPE), containing the SICP network as a salt and traditional dual-ion lithium salt, is designed for retarding the movement of free anions and simultaneously providing sufficient effective carriers to alleviate concentration polarization. The dual salt network of this designed QSPE is prepared through in-situ crosslinking copolymerization of SICP monomer, regular ionic conductor, crosslinker with the presence of the dual-ion lithium salt, delivering a high lithium-ion transference number (0.75) and satisfactory ionic conductivity (1.16 × 10−3 S cm−1 at 30 °C). Comprehensive characterizations combined with theoretical calculation demonstrate that polyanions from SICP exerts a potential repulsive effect on the transport of free anions to reduce concentration polarization inhibiting lithium dendrites. As a consequence, the Li||LiFePO 4 cell achieves a long-cycle stability for 2000 cycles and a 90% capacity retention at 30 °C. This work provides a new perspective for reducing concentration polarization and simultaneously enabling enough lithium-ions migration for high-performance polymer LMBs. [ABSTRACT FROM AUTHOR]

Samarium praseodymium (Sm–Pr) co-doped ceria was synthesized by the co-precipitation technique as an electrolyte for low-temperature solid oxide fuel cell (LT-SOFC) applications. The structural, morphological, compositional, and electrical characterization of the synthesized samples were evaluated via x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX) and impedance spectroscopy. The generation of a single-phase fluorite structure of co-doped ceria without any secondary phases has been verified by XRD analysis, exhibiting the successful incorporation of Sm and Pr ions into the ceria lattice. Vegard's law is utilized for Pr redox behavior explaining the variation in lattice constant values. SEM pictures show that the co-doped ceria powder has a homogeneous and well-dispersed microstructure, and has enhanced particle size. The impedance spectroscopy results indicate that Sm–Pr co-doped ceria has much higher ionic conductivity than single-doped ceria. The highest amount of ionic conductivity (σ i o n i c ) for the composition Ce 0.80 Sm 0.10 Pr 0.10 O 2 − δ recorded as 2.12 × 10 − 2 S / c m at 500 ° C , and 6.19 × 10 − 2 S / c m at 750 ° C with the lowest activation energy E a = 0.48 e V , which has been not reported earlier. Sm and Pr are chosen as dopants because of their capacity to generate oxygen vacancies and improve ceria's ionic conductivity. This study contributes to the enhancement in the ionic conductivity of co-doped ceria by co-precipitation technique and the temperature-dependent frequency exponent factor "s" is also explored to comprehend the conduction mechanism of the prepared samples. [ABSTRACT FROM AUTHOR]

Owing to structure advantages, poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) has garnered significant attention in the field of anion exchange membranes (AEMs) for fuel cell applications. However, its low ionic conductivity has remained a formidable obstacle for high-performance SEBS based AEMs. Herein, an innovative approach is employed, incorporating ionic oligomeric polystyrene (OPS) into physically crosslinked SEBS based AEMs, to fabricate two series of OPS/SEBS AEMs via precise control of the molecular weight and load ratio of OPS, respectively. The variables are theoretically capable of decreasing the glass transition temperature (T g) of the polystyrene phase below the operating temperature of fuel cells. The results demonstrate that the lower molecular weight and the higher load quantity of OPS not only broaden the ion transport channels but also lower the energy barrier of the conducting polystyrene phase. Remarkably, the membrane (1300-CHM–OH–35) with an IEC of 2.41 mmol g−1 significantly improved the ionic conductivity to 150.9 mS cm−1 at 80 °C, despite its low total polystyrene content (45.78%), and attained a peak power density of 506.26 mW cm−2 at 1100 mA cm−2 in a H 2 /O 2 single cell operating at 70 °C. This outstanding performance underscores the promising potential of our approach in the development of high-performance SEBS AEMs for fuel cell applications. [Display omitted] • A series of SEBS based AEMs with broaden ion transport channels was synthesized. • The AEMs show good ionic conductivity and alkaline stability. • A new approach of loading ionic oligomers is used to prepare high-performance AEMs. [ABSTRACT FROM AUTHOR]

Doped barium stannate belongs to the perovskite-structured complex oxides with proton transport capability. Such objects are of high interest in terms of their application in various protonic ceramic electrochemical cells. In the present work, In-doped barium stannate (BaSn 1−x In x O 3−δ , 0 ≤ x ≤ 0.4) materials were prepared and thoroughly characterized by structural, microstructural, and electrochemical techniques. The single-phase and high-dense ceramic materials were prepared by the conventional solid-state synthesis route over the entire doping range investigated. The chemical composition of these materials was found to be in close agreement with the nominal values, indicating no evaporation of Ba-, Sn-, or In-containing phases during sintering. The high-temperature electrochemical analysis showed that the ionic conductivity of BaSn 1−x In x O 3−δ gradually increases with increasing the In-content without reaching a concentration maximum, even for high dopant concentrations. The relatively high activation energy values indicate that this ionic conductivity is determined by oxygen-ionic transport, which, however, becomes predominantly protonic at reduced temperatures. The determination of bulk and grain boundary transport showed that both were improved with the In-doping. The possible reasons for these observations were discussed in detail in this work. Therefore, the obtained data are important for discovering the transport properties of stannates and their potential applications. [Display omitted] • In-doped BaSnO 3 materials (BaSn 1−x In x O 3−δ , 0 ≤ x ≤ 0.4) were successfully prepared. • Single-phase and high-dense ceramics were prepared for all In-concentration. • Electrical properties of BaSn 1−x In x O 3−δ were comprehensively studied at 200–900 °C. • Ionic conductivity of BaSn 1−x In x O 3−δ continuously increases with In-doping. • BaSn 1−x In x O 3−δ are MIEC materials in both oxidizing and reducing atmospheres. [ABSTRACT FROM AUTHOR]

Developing proton-exchange membranes (PEMs) for energy applications is necessary for fulfilling the increasing energy demand without environmental effects. In this study, we prepared composite membranes containing mercaptoethanol-assisted sulfonic acid-functionalized polysiloxanes (MASFPs) and perfluorinated sulfonic acid (PFSA). The MASFP-containing composite membrane (i.e., CMASFP-2) exhibited better membrane properties than the composite membrane prepared without mercaptoethanol (CMASFP-1) and the reference Nafion 212 membrane. Wide-angle X-ray diffraction (XRD) studies revealed a broad peak at 2θ = 17.4° and 39°, indicating that the composite membranes are semicrystalline. Scanning electron microscopy (SEM) analysis revealed that the prepared composite membranes had good morphology, whereas energy-dispersive X-ray spectroscopy analysis revealed that it had siloxane and more sulfonic acid than the pristine PFSA membrane. Thermogravimetric and mechanical strength analyses revealed that incorporating sulfonic acid-functionalized siloxanes improved the thermal stability and mechanical strain of the membrane. The prepared CMASFP-2 membrane had a high ionic conductivity of 0.106 mS cm−1 and an ion-exchange capacity of 1.09 meq·g−1. CMASFP-2 also exhibited lower hydrogen gas permeability than the Nafion 212 and PFSA membranes, demonstrating that it can be used for energy applications. [Display omitted] • A new sulfonic acid-functionalized siloxane was used in composite membranes with PFSA. • The addition of mercaptoethanol enhanced the sulfonic acid amount in the siloxanes. • The CMASFP-2 membrane had a better ionic conductivity and ion-exchange capacity than Nafion 212. • The addition of siloxane improves mechanical strain and lowers H 2 gas permeability. [ABSTRACT FROM AUTHOR]

Perovskite oxide La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3 (LSGM) is an intermedium-temperature solid oxide cell electrolyte material with extraordinary oxygen-ion conductivity. However, the manufacturing procedures of LSGM discs are complex involving multiple steps of powder preparation, forming, and sintering at high temperatures. Herein, thin LSGM electrolyte discs are prepared by coupling of tape casting and in situ solid-state reaction using oxides/carbonates as the feedstock. A pure-phase LSGM electrolyte disc with uniform elemental distribution is obtained by sintering at 1450 °C, and it possesses an ionic conductivity of 0.105 S cm 1 at 800 °C, a thermal expansion coefficient of 12.2 × 10 6 K 1, and a bending strength of 156 MPa A 170 µm thick LSGM electrolyte-supported single cell delivers a peak power density of 0.96 W cm 2 at 800 °C and an electrolysis current density of 1.82 A cm 2 at 1.5 V with no noticeable degradation for 200 h. The findings of this research provide a cost-effective approach for manufacturing the LSGM electrolytes of efficient and durable solid oxide cells. • Thin LSGM discs are prepared by coupling of tape casting and in situ solid-state reaction. • Pure-phase LSGM discs are produced with favourable physical properties. • A LSGM-supported single cell exhibits outstanding output performance and durability. [ABSTRACT FROM AUTHOR]

Herein, we present the results of a study of nanopowders of Ag 6.25 P 0.75 Ge 0.25 S 5 I, Ag 6.5 P 0.5 Ge 0.5 S 5 I solid solutions, and ceramic materials based on them. Nanopowders were obtained by dry grinding in a ball mill and characterized by XRD and SEM. Solid solutions based ceramic materials obtained by annealing of pressed disks were studied by SEM, EDS, EIS, and microhardness measurement. The SEM method revealed a change in the size of crystallites during recrystallization. The frequency dependence of the electrical conductivity is typical for superionic conductors. For ceramics of the composition Ag 6.5 P 0.5 Ge 0.5 S 5 I, a slight increase in ionic electrical conductivity of 3.62 × 10–2 S/cm (30 min) and 3.84 × 10–2 S/cm (60 min) is observed with a decrease in crystallite size. For the entire series of solid solutions of Ag 6+x (P 1−x Ge x)S 5 I, a comparative analysis of the parameters of ceramics made from micro- and nanocrystalline powders (with different grain sizes) with single crystalline samples was performed. [ABSTRACT FROM AUTHOR]

This work shows the synthesis, characterization and evaluation of dense-ceramic membranes made of Ce 0.85 Gd 0.15 O 2-δ -LaNiO 3 (CG-LN) composites, where the fluorite-perovskite ratio (CG:LN) was varied as follows: 75:25, 80:20 and 85:15 wt.%. Supports were initially characterized by XRD, SEM and electrical conductivity (using vacuum and oxygen atmospheres), to determine the composition, microstructural and ionic-electronic conductivity properties. Later, supports were infiltrated with an eutectic carbonates mixture, producing the corresponding dense dual-phase membranes, in which CO 2 permeation tests were conducted. Here, CO 2 permeation experiments were performed from 900 to 700°C, in the presence and absence of oxygen (flowed in the sweep membrane side). Results showed that these composites possess high CO 2 permeation properties, where the O 2 addition significantly improves the ionic conduction on the sweep membrane side. Specifically, the GC80-LN20 composition presented the best results due to the following physicochemical characteristics: high electronic and ionic conductivity, appropriate porosity, interconnected porous channels, as well as thermal and chemical stabilities between the composite support and carbonate phases. [ABSTRACT FROM AUTHOR]

Room temperature water splitting due to reactive surface charges created by defects and porosity in metal oxides fabricated as Hydroelectric Cell (HEC) has translated it into electric current and voltage. Novel oxygen-deficient, nanoporous nanocomposites [(1- x) Na 0.5 Bi 0.5 TiO 3 - (x) MgFe 2 O 4 (x = 0, 0.2, 0.5, 0.8 and 1)] denoted as (1- x) NBT - (x) MFO used as multiferroic, have been prepared by solid state reaction for water splitting. NBT-MFO based hydroelectric cell has been fabricated to generate current and voltage by water splitting. Maximum offload current 8.23 mA and voltage 1 V has been recorded for 0.50NBT-0.50MFO nanocomposite based hydroelectric cell of area 2 × 2 cm2. Dissimilarity in ferroelectric-ferrite phase in nanocomposites generates strain in the perovskite phase evaluated by W–H plot analysis of X-Ray diffraction patterns. The validation of oxidation states of cations and the highest oxygen vacancies ratio of 80% has been calculated by X-ray photoelectron spectroscopy (XPS) peak area. The interstitial defects in nanocomposites have been analyzed by PL emission spectra. The actual charge transfer processes in HEC have been studied by circuit modeling of Nyquist plot by Electrochemical Impedance Spectroscopy (EIS). By virtue of utmost defects, highest nanoporosity and extremely low charge transfer impedance (1.169 Ω), nanocomposite 0.50NBT-0.50MFO delivered significant short circuit current. Furthermore, nanocomposites based HECs stand out as economical, facile and eco-friendly energy devices with no harmful by-products. [ABSTRACT FROM AUTHOR]

Ideally, a solid electrolyte which is a central component of SOFC should exhibit high anionic or cationic ionic conductivity at the proposed operating temperatures. In most cases, the performance is compromised when operating above 1000 °C due to poor mechanical, thermal and chemical stability of selected functional and non-functional materials. In this context, pyrochlores are one of the potential candidates due to their high conductivity, flexibility to accommodate large cations, and high mechanical, thermal and chemical stability. In this study, we report the synthesis of nano-powders of Ho 2 Hf 2 O 7 (HH) and Ho 2 Zr 2 O 7 (HZ) pyrochlore ceramics by eco-friendly alginate mediated ion-exchange process also known as Leeds Alginate Process (LAP) and provide further insight into the structure - conductivity relationship of HH and HZ compounds by EXAFS studies. Both the compositions were sintered at temperatures, ranging from 1100 °C-1500 °C at 2 h dwell time to achieve the desired high-density ceramic with stable pyrochlore structure. X-ray diffraction and Extended X-ray absorption fine structural (EXAFS) analysis showed superlattice reflections and complex coordination geometry of these oxides. The coordination number and disorder factor in the case of HZ were found to be more stable than the HH sample, as evident from the EXAFS. Impedance spectroscopy and dc-conductivity analysis showed a better charge transport behavior in HZ ceramics than in HH making HZ as a preferred solid electrolyte for SOFC. The conductivity of Ho 2 Zr 2 O 7 is comparable with the best-known fluorite oxide-ion conductor such as Sc 2 O 3 -stabilized ZrO 2 at 500 °C. [ABSTRACT FROM AUTHOR]

In this study, a series of pyrochlore-type compounds (Y 2-x Zn x)Ti 2 O 7- δ with x = 0.0, 0.1, and 0.2 were synthesized using the molten salt method. The samples were studied by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and UV–visible spectroscopy. Rietveld refinement of the XRD patterns shows that Zn2+ ions occupy Y3+ sites. Consequently, a lattice parameter and ionic radius ratio r A /r B decrease; consequently, the crystal structure is less ordered. Raman spectroscopy shows that the disorder manifests by broadening of FWHM Raman modes and increasing the A 1g Raman mode frequency as the Zn content (x) rises. Another repercussion arising from the disorder observed in the pyrochlore is the occurrence of oxygen vacancies, which are associated with ionic conductivity and are localized at 531 eV in the high-resolution O1s XPS spectra. First-principles studies using LDA + U show that Y 2 Ti 2 O 7 has a 3.07 eV electronic band gap, slightly lower than the 3.12 eV experimentally reported. The valence band (VB) is a contribution of O 2p hybridized states with Ti-3d and Y-4d, while the conduction band (CB) has Ti-3d states hybridized with O-2p states. The VB XPS spectrum and calculated DOS for Y 2 Ti 2 O 7 are well correlated. As the Zn content (x) increases, the VB XPS spectra shift to low energies, with an increment in partial states at zero eV, which induces an increase in the carrier charge. UV–visible absorption measurements using the Tauc plot approximation show a decrease in the optical band gap due to an increased concentration of Zn content. [ABSTRACT FROM AUTHOR]

Among all the cathode materials in lithium-ion batteries (LIBs), V 2 O 5 has gained a lot of attention due to its high theoretical specific capacity (∼440 mAh g−1). However, only some of the lithium-ions can be reversibly extracted after inserting into V 2 O 5 cells, making the actual reversible capacity of the crystalline V 2 O 5 cathode material much lower than its theoretical specific capacity. In this work, we prepared Li 2 O–V 2 O 5 –P 2 O 5 ternary glass by melt-quenching method. Subsequently, we grew nano-sized crystals and super-lattice structures in the glass matrix by precise heat treatment. Systematic structural, electrochemical tests and first-principles computations have shown that a reasonable amount of super-lattice structure can significantly enhance the electronic and ionic conductivity of glass matrix materials. Benefiting from this, the LVP-70-2 composite cathode exhibited excellent lithium storage performance with a stable reversible capacity of nearly ∼280 mAh g−1 at 50 mA g−1 and an outstanding cycling performance of a remaining capacity of 90 mAh g−1 at 1600 mA g−1 after 200 cycles. [ABSTRACT FROM AUTHOR]

Garnet-structured Li 7 La 3 Zr 2 O 12 (LLZO) is an attractive electrolyte for lithium solid-state batteries (SSBs), but its processing requires long sintering at temperatures above 1000 °C to achieve sufficient ionic conductivity. Such sintering is not only time and energy consuming, but also leads to undesirable material interactions. Therefore, a significant reduction of the sintering time is very important for the future development of garnet-based batteries. A promising method is the recently introduced photonic blacklight sintering with light sources in the UV spectrum, which enables energy-efficient sintering of ceramic layers within seconds. In this work, blacklight sintering of garnet-based SSBs is validated using a model cell consisting of LLZO and LiCoO 2 (LCO) composite cathode layers printed on dense LLZO pellets. An optimized sintering program allowed the production of working cells in only 20 s. This study demonstrates the suitability of blacklight sintering for processing garnet-based SSBs and provides guidance for future process optimization. [ABSTRACT FROM AUTHOR]

NASICON-structured Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) solid electrolyte has low grain boundary conductivity, which impedes its practical application. Herein, W was adopted to partially replace the Al element in LATP to improve its grain boundary conductivity. The W doping reduces the crystal lattice of the electrolyte, which is detrimental to the grain conductivity. But the doping of W can make the grains closely connect and reduce the voids between the grains, which can greatly enhance the grain boundary conductivity. The LATP sample with the W doping content of 0.03 (LATWP003) exhibits the highest total ionic conductivity of 1.186 mS/cm at 30 ℃, which results from the optimum grain boundary conductivity of 2.315 mS/cm. Moreover, the LATWP003 electrolyte displays a negligible electronic conductivity of 2.01×10−9 S/cm. The LiFePO 4 /LATWP003/Li battery with PVDF-HFP polymer protective layer can be charged and discharged. Therefore, the W doped LATP sample is a promising electrolyte for lithium-ion batteries. [ABSTRACT FROM AUTHOR]

To achieve a coating density meeting the solid oxide fuel cell (SOFC) electrolyte requirements of high gas tightness and ionic conductivity, in this study, a new interface healing densification process based on a liquid-phase sintering induction mechanism was conducted on plasma-sprayed 8 mol% Y 2 O 3 -stabilized ZrO 2 (8YSZ) coatings. Using Fe 2 O 3 and Bi 2 O 3 as healing additives, metallurgical healing of unbound interfaces was achieved by impregnating the additives into the gap interfaces, followed by liquid-phase sintering at 1200 and 1050 °C. After healing, the YSZ coating exhibited a dense bulk-like microstructure with a significant reduction in the gas leakage rate by two orders of magnitude, and the oxygen ion conductivity of the coating was significantly increased. The YSZ coating healed with the Fe 2 O 3 additive showed an oxygen ionic conductivity nearly one order of magnitude higher than that of the as-sprayed coating, reaching more than 80% of the value of the high-temperature-sintered YSZ bulk. • A new interface healing process based on liquid-phase sintering was conducted on APS YSZ coatings. • The interface-healed YSZ coating exhibited a dense bulk-like microstructure. • The gas leakage rate of the interface-healed YSZ coating decreased by two orders of magnitude. • Ionic conductivity of the interface-healed YSZ coating reached > 80% of the sintered bulk. • The cell assembled with interface-healed YSZ-Fe 2 O 3 electrolyte achieved MPD of 1.04 W/cm2 at 800 °C. [ABSTRACT FROM AUTHOR]

In this work, a porous Co 3 O 4 anode material with capsule–shaped morphology is prepared by a simple solvothermal method and subsequent heat treatment process in air. The as–synthesized CoCO 3 precursor and Co 3 O 4 sample are systematically studied and analyzed by a series of testing technologies, such as XRD, FTIR, FESEM, (HR)TEM, TGA, XPS and N 2 adsorption/desorption measurement. As negative materials in Li–ion batteries, the Co 3 O 4 active material exhibits high charge/discharge specific capacity, good rate performance and satisfactory cycle stability. The excellent electrochemical properties are inevitably related to the structural characteristics of the electrode material itself, including regular morphology, rich pore structure, large specific surface area, high crystallinity, nanoscale particle size, etc. [ABSTRACT FROM AUTHOR]

Chalcogenide solid states electrolytes (SSEs) are considered as one of the most promising alternative to replace liquid electrolytes for their high ionic conductivity and appropriate mechanical properties. However, the commercial applications of chalcogenide SSEs in all-solid lithium-ion batteries (ASSIBS) are still limited by the inferior interfacial stability, which leads to lithium dendrite growth and continual interphase formation. Here, the interfacial stability of Li 2 S–P 2 S 5 –B 2 S 3 SSEs have been enhanced effectively via LiI incorporation. In detail, a series of (100- x) (75Li 2 S–15P 2 S 5 –10B 2 S 3)- x LiI (x = 0, 5, 15, 30, 40) SSEs are prepared via ball-milling and then melt-quenching, which exhibit a high ionic conductivity of 1.53 mS cm−1 and a steady long cycling life up to 1637 h without obvious resistance growth at 0.1 mA cm−2. This excellent cycle life is originated from the electronic insulation interphase containing LiI without unaltered the "multi-layer mosaic like" structure of Li 2 S–P 2 S 5 –B 2 S 3 ternary glass system. In addition, this work also confirmed that LiI can act as a catalyst to enhance the charge transfer kinetics within S composite electrode thereby reducing the interface impedance. The stable interface performance obtained by this work could facilitate the development of ASSIBS with prolonged cycle life. [ABSTRACT FROM AUTHOR]

This study focuses on developing a perovskite Li 3x La 2/3-x TiO 3 (LLTO) electrolyte using a simple and effective sol-gel technique. This study aims to enable the hopping of lithium ions in lanthanum sites, which enhances the overall ionic conductivity of the material. By employing an ion conduction mechanism, we investigated the conductivity of powdered and pelletized (dense) LLTO materials. Dense-LLTO exhibits a higher grain ionic conductivity of σ = 1.32 × 10−4 S/cm at room temperature, whereas powdered-LLTO gives a significantly lower conductivity. This significant difference in conductivity can be attributed to the closely packed arrangement of ions in the dense-LLTO structure, which minimizes the evaporation of lithium (Li) in lanthanum (La) sites and promotes ion mobility. Therefore, the thermal treatment process plays a crucial role in facilitating the ion(s) movement and its impact on the ionic conductivity of LLTO, which is mainly influenced by the lithium content. To further evaluate the practical application of LLTO as a solid electrolyte, we constructed a solid-state device with LiFePO 4 /LLTO/AC. The LLTO electrolyte is sandwiched between the activated carbon and LiFePO 4 electrodes. This device exhibits an impressive energy density, achieving 2.42 Wh/kg and a power density of 192 W/kg. Moreover, the device demonstrates better rate capability, allowing for efficient charge and discharge processes. Remarkably, the cyclic stability analysis revealed a retention rate of 92 % over 10,000 cycles, indicating the robustness and durability of the LLTO-based solid-state battery system. These findings highlight the potential of LLTO as a promising solid electrolyte material for advanced energy storage devices. The sol-gel synthesis method provides a simple and effective approach for obtaining high-performance LLTO electrolytes. The enhanced ionic conductivity and excellent electrochemical performance of the solid-state LiFePO 4 /LLTO/AC device demonstrate the feasibility and prospects of LLTO-based batteries in practical applications, offering improved energy density, power density, and long-term cycling stability. [ABSTRACT FROM AUTHOR]

Bulk glass-ceramic solid electrolytes of the Li 2 O–Al 2 O 3 –TiO 2 –P 2 O 5 –SiO 2 system were prepared by melt-quenching and one-step heat treatment method in this work. The effects of the gradual substitution of Al3+ by Cr3+ and the elevation of the heat treatment temperature on the phase composition, microstructure, and ionic conductivity of the solid electrolytes were systematically investigated. The results show that the major crystalline phase is LiTi 2 (PO 4) 3 , and the conductivity of the glass-ceramics initially enhances and then decreases as the Cr 2 O 3 content increases from 0 mol% to 3 mol%. The highest conductivity is obtained when the Cr 2 O 3 content is 2 mol%, measuring 4.45 × 10−4 S/cm at 25 °C. Additionally, the mechanism of the surface exfoliation of the glass-ceramics and the enhancement achieved by doping with Cr3+ are explained according to microstructure analysis. This work provides a simple method to enhance the electrical conductivity and physical properties of LATP glass-ceramic solid electrolytes, which is of great significance for the design of lithium-ion solid electrolytes. [ABSTRACT FROM AUTHOR]

All-solid-state lithium batteries have great potential applying to the fields of transportation and portable devices because of their high safety and energy density as the power source. As a critical component of device, solid-state electrolyte has been paid much attention. Given the excellent physical and chemical stability, Li 1+ x Al x Ti 2- x (PO 4) 3 (LATP)-based electrolyte has been considered as one of the most promising electrolytes for the next generation batteries. However, a further promotion of its ionic conductivity becomes extremely difficult, originating mainly from the poor connection of grains and a low relative density of LATP. Here, the nanosized and homogenous LATP (x = 0.3) powders were synthesized through reducing the agglomeration of precursor powders and preparing at low temperatures. It is revealed that uniformly superfine LATP powders are able to improve the microstructure of grain boundaries during the pellet sintering process, thereby reducing the grain boundary resistance. Furthermore, as-synthesized nanosized powders mixed with Bi 2 O 3 additive present a better enhancement on the connection of grains and the relative density in LATP. On the basis of this understanding, we prepared LATP electrolytes with 0.5 wt% Bi 2 O 3 exhibiting a high ionic conductivity of 8.56 × 10−4 S/cm, a high relative density of 94.4 % and a low activation energy of 0.27 eV, which is demonstrated as a prospective electrolyte in all-solid-state lithium battery LiFePO 4 /PEO/LATP/PEO/Li. [ABSTRACT FROM AUTHOR]

For ceramic fuel cells with low temperatures operation (LT-CFCs; 350°-550 °C), increasing the ionic conductivity and improving the oxygen reduction electrocatalytic activity response at low operating temperatures would be highly desired. This Study presents a novel semiconductor heterostructure composite with a competent electrolyte membrane for LT-CFCs. The composite comprises CoAl 2 O 4 (CA) in a spine-like structure and wurtzite-structured ZnO. We have demonstrated a button-sized CFC under H 2 and ambient air environment delivering a high power density of 835 mW-cm−2 at 550 °C, with potential operating up-to 400 °C. Compared to ZnO and CA alone, the CA-ZnO heterostructure composite has reduced oxygen vacancy production and activation energy, facilitating ion transport more quickly through the CA-Zn interface. Density functional theory (DFT) computations, photoelectron spectroscopy, U-visible, X-ray diffraction, and HR-TEM are the characterization techniques used to study the enhanced ionic conduction of the CA-ZnO heterostructure composite. These results imply that the heterostructure approach works better than the simple bulk structure for the electrolyte application of LT-SOFCs. [Display omitted] [ABSTRACT FROM AUTHOR]

A new preparation technique of Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) ceramics is focused on optimisation of weight fractions of LATP glass additives into green ceramic powder followed by enhanced two-step sintering to improve key parameters of relative density and ionic conductivity of LATP solid-state electrolyte (SSE) pellets. The LATP SSE has been obtained with the relative density and ionic conductivity of (96.3±0.2)% and (8.0±0.2)×10−4 S/cm, respectively, after pre-annealing at 570°C for 6 h and sintering at 900°C for 6 h of mixed glass and ceramic powders with an optimal weight ratio of 5%/95%. Notably, the Li||LATP||Li symmetric cell using such LATP SSE could maintain voltage stability for 300 h, and the Li||LATP||NCM111 full cell exhibits good cycling performance over 100 cycles with capacity above 100 mAh/g (capacity retention of 79.1%). The proposed simple technique seems to be effective to improve the relative density and ionic conductivity thus acclerating the development of all-solid-state lithium metal battery. [ABSTRACT FROM AUTHOR]

The increasing necessity of high ionic conductor for solid state electrolytes implies the enhancement of our understanding in the relationship between doping-microstructure-ionic conductivity. In the current study, Li 0.5 La 0.5-x Ce x TiO 3 (0.00 ≤x ≤ 0.05) perovskites are obtained using the sol-gel method to evaluate the effects of cerium doping on microstructure and conductivity. The results confirms that all samples present a tetragonal perovskite structure with the lowest energy gap of 1.67eV for x = 0.01 of Ce3+, this particular composition present an average grain size of 2.026 μm and the highest relative density (92.02 %), bulk and grain boundary conductivities in the order of 1.949 × 10−3 S/cm and 1.671 × 10−6 S/cm, respectively at room temperature. These conductivity values are approximately an order of magnitude higher than the Ce-free material, thanks to the optimized relative density and adequate grain size. [ABSTRACT FROM AUTHOR]

Ionic thermoelectric effect based on thermal migration of ion in the pore solution is emerging as a new branch of research on the thermoelectric effect of cement-based materials. However, the dense and tortuous pore structure of the cementitious materials may limit the ionic electrical conductivity and reduce the ionic thermal migration in pore solutions. Therefore, improving the pore structure may be a promising direction to enhance the thermoelectric effect of pore solution in cementitious materials. In this study, the pure cement paste with three water-cement ratios (w / c ratio = 0.3, 0.4, 0.5) and two curing methods (sealed curing and wet curing) are used. The effects of the ion concentration of the pore solution on the electrical conductivity and the Seebeck coefficient are investigated by the treatment of the vacuum saturation and the leaching process of the cement pastes. In addition, the pore structure of the cement paste is measured by mercury intrusion porosimetry (MIP). The effect of pore structure on the ionic thermoelectric effect of the cement pastes is studied. The results show not only the porosity and pore connectivity, but also the higher specific surface area of cement matrix is an important parameter for improving the ionic Seebeck coefficient of cementitious materials. The finer pore distribution in the cement matrix will cause a larger thermoelectric voltage. By improving the pore structure, the power factor (PF) of cement paste has been improved by two orders of magnitude, from 0.0027 μWm−1K−2 to 0.178 μWm−1K−2. The findings of this study can guide further understanding of the ionic thermoelectric effect of cementitious materials and provide a method for enhancing the thermoelectric effect of high-efficiency ionic thermoelectric materials (such as polyelectrolytes and ionic liquid) in cement matrix, which can develop ultra-high performance ionic thermoelectric cement-based materials for zero energy buildings. [ABSTRACT FROM AUTHOR]

Proton-conducting solid oxide fuel cells (H-SOFCs) are appealing for low-to-intermediate temperature operation due to their intrinsic lower activation energy and better ionic conductivity. Unfortunately, there are currently few acceptable and high-performing cathode materials available for H-SOFCs. Herein, we present a novel high performance multicomponent Ruddlesden-Popper (RP) type cathode Pr 3 Ni 1.5 Cu 0.3 Nb 0.05 Ta 0.05 Zr 0.05 Y 0.05 O 7-δ (PNCNTZY) with superior triple conducting property. The multicomponent co-doping of Nb, Ta, Zr, and Y brings about the enhancement of configurational entropy and cocktail effect for improving H+/O2-/e- triple conductivity and oxygen vacancy concentration. Naturally, the ORR activity is improved by facilitated charge transfer and oxygen surface exchange, exhibiting reduced polarization resistance to just 0.24 Ω cm2 at 550 °C. When used as the cathode in H-SOFC single cells, excellent power production is demonstrated at 550 °C, with a peak power density of up to 0.84 W cm-2. Furthermore, the PNCNTZY sample shows adequate thermal compatibility with proton conductor electrolytes BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ (BZCYYb) and then appropriate endurance durability (0.8 A cm-2 at 550 °C for about 250 h) due to their match of thermal expansion coefficient (TEC) brought about by the Co-free and partial replacement of larger-size elements. This extremely promising Co-free RP perovskite cathode for H-SOFCs produced by this work might provide a new type candidate and novel strategy for the commercialization of H-SOFCs. [Display omitted] • Multicomponent Co-free Pr 3 Ni 1.5 Cu 0.3 Nb 0.05 Ta 0.05 Zr 0.05 Y 0.05 O 7-δ (PNCNTZY) was developed as H-SOFCs cathode. • PNCNTZY cathode has RP structure and triple-conductivity (H+/O2-/e-). • Multicomponent co-doping significantly improved ORR activity and triple conductivity. • Single cell with PNCNTZY cathode shows excellent peak power densities (0.84 W cm-2 at 550 °C) and durability. [ABSTRACT FROM AUTHOR]

Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) NASICON-type ceramic, due to its high bulk conductivity, is believed to be one of the most appropriate material for application as solid electrolyte in all-solid-state lithium-ion batteries. However, its highly resistant grain boundaries strongly limit the total ionic conductivity. Therefore, in this work, an attempt has been made to overcome this problem by introducing a Li-ion conducting additive LiAlSiO 4 (LASO) to LATP base matrix in order to provide more conduction paths for lithium ions between grains. The properties of Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 –xLiAlSiO 4 (0.02 ≤ x ≤ 0.1) composite system were studied by means of: high-temperature X-ray powder diffractometry (HTXRD), 6Li, 27Al, and 31P magic angle spinning nuclear magnetic resonance spectroscopy (MAS NMR), scanning electron microscopy (SEM), and impedance spectroscopy (IS) methods. The obtained ceramic LATP–LASO materials exhibited high values of bulk conductivity, above 10−3 S/cm, and good total conductivity, exceeding 10−4 S/cm. The factors responsible for the enhancement, but also for the deterioration of total conductivity, i.e. microstructure and grain boundaries, are identified and discussed in this work. [ABSTRACT FROM AUTHOR]

Anion exchange membranes (AEMs) act as the heart of anion exchange membrane fuel cells (AEMFCs). To address the challenges of the chemical stability of AEMs and the trade-off between ionic conductivity and dimensional stability. Here, we report the non-covalent crosslinking strategy. The synergistic interaction of cation-dipole interactions and hydroxyl groups provide a dense hydrogen bonding network and form non-covalent crosslinking. The QPBTTP-PEG-10 membrane has a low swelling ratio (28.62%) and excellent hydroxide conductivity (127.76 mS cm−1) at 80 °C. Furthermore, the QPBTTP-PEG-10 treated in 3 M NaOH for 1200 h maintined ≥90.87% of its hydroxide conductivity. In addition, excellent thermal stability and mechanical properties (58.92 MPa and can withstand more than 10,000 times its own weight). The open circuit voltage and peak power density of QPBTTP-PEG-10 are 0.988 V and 369.64 mW cm−2 at 80 °C in H 2 –O 2 with A/C dew points of 75 °C/77 °C. [Display omitted] • QPBTTP-PEG-10 with low swelling and excellent hydroxide conductivity. • QPBTTP-PEG-10 can withstand more than 10,000 times its own weight. • Hydrogen-bonds between C – O –C bone and hydroxyl groups construct new OH− transport channels. • Dynamic non-covalent cross-linking promote the self-aggregation of cations and then enhance OH− transfer. [ABSTRACT FROM AUTHOR]

Improving the microphase separation structure of membranes is considered an effective strategy to solve the trade-off problem, which can increase the conductivity and reduce the swelling. This article designs poly(aryl alkylene) AEMs with different aryl backbone chains (biphenyl, p-terphenyl and m-terphenyl), with the goal of examining the effect of spatial structure main chains on the membrane performance. It is found that the membrane (m-QTPNP) has a better microphase separation structure and a conductivity of 143.5 mS cm−1 (80 °C) via SAXS, TEM and AFM. Due to the lower IEC (2.23 meq g−1), m-QTPNP has a good anti-swelling performance. During tensile testing, the elongation at break of m-QTPNP can reach 105.5% (wet state). Moreover, due to the obvious microphase separation, the attack of OH− on the quaternized groups is reduced, and m-QTPNP has a conductivity retention rate of 95.5% (80 °C, 2 M NaOH, 1560 h). In addition, the peak power density (PPD) of the H 2 /O 2 single cell equipped with m-QTPNP can reach 749 mW cm−2 (80 °C). After 90 h of durability testing, the voltage decayed to 92.2%, with a decay rate of 0.54 mV h−1. • The m-QTPNP AEM shows excellent mechanical properties with elongation at break up to 105.5% in wet state. • The m-QTPNP AEM exhibits an ionic conductivity of 143.5 mS cm−1 at 80 °C. • The peak power density of m-QTPNP in a H 2 /O 2 single cell is 749 mW cm−2. [ABSTRACT FROM AUTHOR]

Anion exchange membranes (AEMs) are the core components of water electrolysis and suffer from the critical obstacles such as low ionic conductivity and poor alkali resistance stability in practical applications. In this work, a series of AEMs based on poly(arylene ether nitrile)s with high-density quaternary ammonium cationic side chains (PAEN-DQA-x) are synthesized to optimize the conductivity and alkali resistance stability. Their surface morphology and microstructure are characterized by scanning electron microscopy and atomic force microscopy, respectively. The obtained AEMs exhibit good conductivity and the values are in the range of 76.13–119.72 mS/cm at 80 °C. The conductivity retention for the representative PAEN-DQA-0.35 membrane is up to 73% after immersion in 2 M NaOH at 80 °C for 480 h. The current density of the water electrolyzer by PAEN-DQA-0.35 reaches 521.3 mA/cm2 at 2.0 V, and it also remains good stable at a current density of 500 mA/cm2 in a 0.1 M KOH environment. [Display omitted] • AEMs based on poly(arylene ether nitrile)s were designed for water electrolysis. • Highly dense quaternary ammonium cationic side chains were introduced. • Good conductivity as well as improved dimensional and alkaline stability. • The electrolyzer achieved good current density and cycling stability. [ABSTRACT FROM AUTHOR]

Developing cathodes that are both phase-stable and tolerant to carbon dioxide (CO 2) is a crucial and challenging task for solid-oxide fuel cells (SOFCs) operating at reduced temperatures. The activity of oxygen reduction reaction (ORR) in SOFC cathodes is typically influenced by factors such as geometric features and oxygen vacancies. In this study, new and robust cathodes for SOFCs, Sr 2 Co 1.5 Fe 0.4 Ta 0.1 O 5+δ (SCFT) and Sr 2 Co 1.5 Fe 0.4 Nb 0.1 O 5+δ (SCFN) are developed by doping a small amount of niobium (Nb) and tantalum (Ta) into Sr 2 Co 1.6 Fe 0.4 O 5+δ (SCF) using a simple solid-state reaction technique. The effects of Nb/Ta doping on the crystal structure, oxygen vacancies, electrical conductivity, and electrochemical properties of SCFT and SCFN are investigated. The results reveal that these materials possess a fully cubic structure in the Fm-3m space group, with improved oxygen vacancy and electrical conductivity. They also exhibit good chemical compatibility with electrolytes at 1100 °C for 8 h and remain thermally stable when exposed to air and CO 2 at 700 °C, without any additional phase formation. The area-specific resistance (ASR) of the SCFT cathode is found to be only 0.06 Ω cm2, whereas the SCFN cathode has an ASR of 0.10 Ω cm2. The superior performance of SCFT can be attributed to the higher oxygen vacancy, which enhances oxygen surface exchange kinetics and diffusivity compared to SCFN. When tested in a single cell using humidified H 2 as the fuel and ambient air as the oxidant, the SCFT cathode achieves a power density of 656 mW cm−2 at 700 °C, while the SCFN cathode reaches 559 mW cm−2, indicating the potential of SCFT as a promising cathode material for SOFCs. The excellent performance of these materials can be attributed to their mixed electronic-ionic conduction properties, unique structural features, and high observed oxygen vacancy, which contribute to their remarkable electronic conductivity and significant ionic mobility. [ABSTRACT FROM AUTHOR]

A series of Tb3+ substituted layered perovskite Sr(La 1- x Tb x)AlO 4 (x = 0–1) was synthesized via solid-state reaction. The influence of Tb3+ on the phase, structure, photoluminescence, and long afterglow properties of the SrLaAlO 4 product was investigated. The fully substituted product SrTbAlO 4 was found to be isostructural with its SrLaAlO 4 counterpart, and the crystal structure parameters were first reported in this work. Photoluminescence investigation found that benefiting from the unique layered crystal structure, the activator Tb3+ was well separated and the optimal doping concentration was found to be as high as 20 at%. Except for photoluminescence, the products simultaneously show long afterglow properties due to disorder cations distribution in the local structure and thus induced defect condition. When the UV light source is turned off, the afterglow luminescence of SrLaAlO 4 : 0.03 Tb3+ can last over 1 h. The trap distribution of SrLaAlO 4 : Tb3+ was analyzed in detail by thermoluminescence. The trap depth is calculated to be around 0.7–0.81 eV, the value of which highly coincides with the ideal energy level for trapping and releasing electrons at room temperature. On the basis of the experimental results, the mechanism of long afterglow luminescence of SrLaAlO 4 : Tb3+ is elaborated and discussed. [ABSTRACT FROM AUTHOR]

Double perovskites of the form R 2 NiMnO 6 (R=Rare-earth) are recognized for their multifunctional nature. Here in this study we have considered one of the members of this class of double perovskites i.e., Nd 2 NiMnO 6 and modified its various physical properties through Ca doping at Nd site. X-ray diffraction patterns and their analysis show the monoclinic structure that can be indexed with P2 1 /n space group for all the three compounds of Nd 2-x Ca x NiMnO 6 (x = 0.0, 0.2 and 0.4). Scanning electron microscopy shows that the grains are irregular in shape and size for the three samples and the average grain size decreases with increase in Ca concentration. The variation of dielectric constant as well as dielectric loss with frequency depicts a decrease in their value with increase in frequency from 20 Hz to 2 MHz. On the other hand the variation of dielectric constant with temperature shows a rise in the value of dielectric constant as the temperature is increased from 100 K to 300 K, while the temperature variation of dielectric loss is associated with relaxation behavior. The peak in the tanδ curve corresponds to the temperature at which the dielectric constant starts increasing and this peak in the dielectric loss gets shifted towards the side of high temperature with the rise in frequency. A rise in the Ca concentration increases the dielectric constant as well as dielectric loss. The ac conductivity for all the three samples of Nd 2-x Ca x NiMnO 6 (x = 0.0, 0.2 and 0.4) rises with rise in temperature indicating the existence of negative temperature coefficient of resistance. The ac conductivity also increases with increase in Ca concentration. A further analysis of conductivity behavior has been done by determining the activation energy through the involvement of the Arrhenius equation. The activation energy decreases with increase in Ca concentration. The resistivity measurements again indicate the existence of negative temperature coefficient of resistance in all the three samples of Nd 2-x Ca x NiMnO 6 (x = 0.0, 0.2 and 0.4) and the value of resistivity reduces as the Ca concentration is increased. The various results obtained in this study have been interrelated. [ABSTRACT FROM AUTHOR]

Oxygen-deficient Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) was prepared using a hydrothermal method followed by high-temperature calcination. Comprehensive analyses using X-ray powder diffraction (XRD), electron paramagnetic resonance (EPR), and X-ray photoelectron spectroscopy (XPS) conclusively demonstrated the successful preparation of oxygen-deficient LATPs under different calcination temperatures in an argon-hydrogen mixed atmosphere. These varying temperatures affected the concentration of oxygen defects in LATP. The hydrothermal precursor was calcined at 700 °C for 6 h to prepare an oxygen-deficient LATP, which was subsequently combined with polyacrylonitrile (PAN) to form a solid composite electrolyte. The composite exhibited a total ionic conductivity of 7.55 × 10−4 S cm−1 at 20 °C. Furthermore, when tested at 25 °C with a current density of 0.025 mA cm−2, the composite displayed good compatibility with a lithium metal anode. At a current density of 0.1 C, the initial discharge capacity was found to be 256.2 mA h g−1, which was maintained at 231.8 mA h g−1 after 100 cycles within the voltage range of 2.0–4.5 V. By judiciously modulating the oxygen defects concentration, it is possible to not only improve the ionic conductivity of the solid composite electrolyte but also to further enhance its discharge capacity. [ABSTRACT FROM AUTHOR]

Rare-earth oxides determine the commercialization and development of solid oxide fuel cells (SOFCs) for all the types, still remining challenges of high cost and low electrochemical performance. Here, we propose an industrial mixed rare-earth oxide fuel cell using the state-of-the-art industrial lanthanum-praseodymium-cerium (La-Pr-Ce, LCP) oxide electrolyte as a proof-of-concept, achieving low-cost and high electrochemical performance. The rare-earth oxides, La 2 O 3 , CeO 2 , PrO 2 and LCP are prepared and studied by oversimplified solid reaction experiments with density functional theory (DFT) calculations. The LCP is simplified as La, Pr doped CeO 2 , in which the effects of rare-earth elements doping are concluded as follows: firstly, the Ce4+/Ce3+ redox pairs can be slightly suppressed by La, Pr co-doping; secondly, the bandgap of LCP is decreased to 2.01 eV with enhanced electron conductivity of 7.4 × 10−5 S cm−1, which may originate from Pr-doping. The power density output of industrial mixed rare-earth oxide fuel cells with La 2 O 3 , CeO 2 , PrO 2 and LCP electrolytes achieve 630 mW cm−2, 639 mW cm−2, 469 mW cm−2 and 797 mW cm−2 at 500 °C, respectively, indicating that the LCP electrolyte presents ascendant performance output with the ionic conductivity of 0.248 S cm−1. The industrial mixed rare-earth oxide fuel cells not only broaden the exploit avenue for industrial mixed rare-earth oxides, but also unravel the roadblock for the industrialization of SOFCs at low temperatures below 500 °C. [ABSTRACT FROM AUTHOR]

This paper elucidates the mechanism of BN as sintering additive and the enhancement for LLZO performance. The introduction of the sintering additive boron nitride (BN) to Li 6.25 Ga 0.25 La 3 Zr 2 O 12 (LGLZO) can effectively eliminate the insulating phase Li 2 CO 3 and form the liquid phase Li 3 BO 3 along the grain boundaries, which significantly enhances the relative density (from 72.4% to 92.9%), ionic conductivity (from 1.3 × 10 − 5 to 6.7 × 10 − 4 S cm − 1 ), mechanical strength (from 1.36 to 5.36 GPa) and air stability (anti-Li 2 CO 3) of the electrolyte. Density functional theory (DFT) results reveal that the formation of Li 3 BO 3 contributes to the improvement of the interfacial lithiophilicity, and the interface resistance is reduced from 1219 to 32 Ω cm−2. The critical current density (CCD) is enhanced from 0.1 to 0.7 mA cm−2, and the cells can be stably cycled for more than 1000 h at a current density of 0.2 mA cm−2 with a low overpotential at room temperature. [ABSTRACT FROM AUTHOR]

Yttria-stabilised zirconia (YSZ) materials are of great interest due to their mechanical properties, chemical inertness, low thermal conductivity and high ionic conductivity. However, a high temperature is required to consolidate the YSZ, while homogeneity problems may arise. This study proposes a modified wet chemical method for commercial YSZ sintering started from a scalable colloidal solution containing yttrium and lithium in an aqueous medium. This homogeneous mixture, adjusted by pH and Li/Y content, transforms into intermediate phases that play a key role as "cement" linking YSZ particles at low sintering temperatures. The originality consists of the use of the citric acid enabling the formation of either porous or dense microstructure depending on processing conditions. A complete follow-up of the transformation of compounds throughout the process, from liquid phase to cement, is proposed and enables us to propose the consolidation mechanism that will be useful for further optimization. [ABSTRACT FROM AUTHOR]

A solution casting technique was used to fabricate a bio-based polymer electrolytes (BBPEs) system in the form of a solid film that is composed of alginate as the host polymer network, glycolic acid (GA) as the charge carrier, and 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) ionic liquid (IL) as an additive. The peak changes in IR spectra revealed the complexation of adding ionic liquids with the enhancement of H+ carriers, while XRD and TGA studies revealed that adding IL suppressed the crystallinity and improved the thermal stability up to ∼100 °C. The free-standing BBPEs sample exhibited the highest ionic conductivity of 2.03 × 10−3 S cm−1 at 6 wt % [Bmim]Cl composition at ambient temperature and achieved an H+ transference number of 0.47. These results suggested that the addition of ILs as an additive into alginate-based BBPEs is a promising strategy for developing proton-conducting solid BBPEs for use in electrochemical devices. [Display omitted] • A bio-based polymer electrolyte composed of alginate-glycolic acid and containing [Bmim]Cl has been successfully prepared. • The BBPEs show that [Bmim]Cl improves physicochemical properties and the conduction of H+. • The increment of ionic conductivity is mainly influenced by μ , D , and η mechanism. [ABSTRACT FROM AUTHOR]

One of the priorities in the field of hydrogen energy is the development of intermediate-temperature (IT-SOFCs) and low-temperature solid oxide fuel cells (LT-SOFCs), which are capable of highly efficient operation in the range of 500–800 °C. The currently applied 8-YSZ electrolytes are expected to be replaced by one based on tetragonal zirconia (3Y-TZP), which is characterized not only by high ionic conductivity below 700 °C, but also significantly higher mechanical strength. One of the candidates is alumina-toughened zirconia (ATZ) with extraordinary mechanical properties (flexural strength of up to 1 GPa and outstanding fracture toughness (K Ic) in excess of 10 MPa m0.5). A series of composites with a nanometric alumina content of 2.3, 10, and 20 vol% were obtained and investigated to evaluate the effects of aluminum addition on the electrical properties of the materials in relation to their microstructure, chemical and phase composition. Measurements performed by means of electrochemical impedance spectroscopy over the range of 300–650 °C showed that the total electrical conductivity of the obtained ATZ samples decreased slightly with increasing content of alumina inclusions and it was around one-third of an order of magnitude lower than that of the reference 3Y-TZP sinter prepared from the commercially available oxide powder containing 3 mol% of yttrium oxide (TOSOH). This is a consequence of the fact that ATZ sinters exhibited a lower specific conductivity of grain boundaries than 3Y-TZP whilst having comparable electrical conductivity of grain interiors. The total electrical conductivity values determined for the ATZ sinters at 700 and 800 °C are approximately the same as the electrical conductivity of 3Y-TZP, and they can therefore be considered a viable alternative to 8-YSZ electrolytes in applications such as IT-SOFCs or LT-SOFCs. [ABSTRACT FROM AUTHOR]

The need to develop safe solid-state lithium batteries has stimulated intense research efforts for Li+ solid electrolytes. However, the low conductivity limits the development of NASICON LiZr 2 (PO 4) 3 (LZP) electrolyte. Here, the doping effects of Ta on the structure, surface morphologies and electrochemical properties of Li 1- x Zr 2- x Ta x (PO 4) 3 (LZTP, x = 0, 0.01, 0.02, 0.04, 0.06 and 0.08) solid electrolyte were analyzed. LZTP was prepared using a simple solid-state reaction route, followed by sintering at 1200 °C for 12 h. A proper content of Ta5+ substitution for Zr4+ is beneficial to stabilize the high conductive rhombohedral (α) phase of LZP at room temperature. Doping Ta5+ is conducive to unblocking of Li+ at the M1 site and facilitates the occupation of Li+ at the M2 site, thereby expanding the pathway for Li+ conduction. Rietveld refinement data demonstrated that the Zr–O and P–O bond lengths (d Zr-O and d P-O) increased with a decrease in Zr–O–P bond angles (θ Zr-O-P) as x rose. The distortions in the ZrO 6 octahedron may weaken the coulomb attraction in Li+-O2-, resulting in a lower activation energy (E a) and a higher Li+ conductivity. The highest room-temperature conductivity (6.06 × 10−5 S cm−1) was obtained at x = 0.06, which reached 1.5 × 10−4 S cm−1 at 50 °C. The E a was found to decrease from 0.388 eV (x = 0) to 0.306 eV (x = 0.06). In addition, Ta doping resulted in improved connectivity and reduced pore formation, which also contributed to the decrease in resistance. The Raman spectrum demonstrated that some phonon modes of bending vibration in PO 4 were degenerate and external modes became too weak to be observed or even disappeared as Ta content increased. This change in the modes also had an impact on the Li+ conductivity. Overall, the LZTP-0.06 appears to be a promising candidate for the solid electrolyte. [ABSTRACT FROM AUTHOR]

The measurement of hydrogen isotopes will be of great interest for future fusion reactors to ensure their proper operation. For this reason, electrochemical sensors will be suitable tools for hydrogen isotopes quantification, as they can perform on-line and in situ measurements. One of the many challenges in hydrogen sensing is finding materials suitable for use at high temperatures and in aggressive environments. In this regard, perovskite-type ceramics exhibit high proton conductivity and excellent physical and chemical stabilities. These properties make perovskite materials ideal candidates for the development of high-temperature hydrogen isotopes sensors. In this study, BaCe 0.6 Zr 0.3 Y 0.1 O 3-α electrolyte was employed to fabricate amperometric sensors to monitor hydrogen isotopes. First, the ionic conductivity of the electrolyte was measured for hydrogen and deuterium using Electrochemical Impedance Spectroscopy (EIS) in order to determine isotopic effects. It was observed a protonic conduction as the governing transport mechanism. In addition, the ratio between the ionic conductivity of hydrogen and deuterium was 1.2–1.4. Then, amperometric measurements were performed at 350, 400, and 500 °C, while maintaining a voltage of 0.15 V between electrodes. The sensors' performance was assessed for hydrogen and deuterium partial pressures ranging from 0.15 to 0.30 mbar within an argon atmosphere. Calibration curves for both isotopes exhibited differences of approximately 20% in their slopes, which agrees with the trend observed in the ionic conductivity results. Additionally, the response time to hydrogen was three times faster compared to that observed for deuterium. These findings suggest that electrochemical sensors utilizing solid-state electrolytes, such as BaCe 0.6 Zr 0.3 Y 0.1 O 3-α , holds great promise as an innovative and effective tool for hydrogen isotope sensing. [Display omitted] • Hydrogen and deuterium isotopic effect was studied on BaCe 0.6 Zr 0.3 Y 0.1 O 3-α (BCZY) electrolyte. • BCZY ionic conductivity was measured for H 2 and D 2 from 150 to 500 °C. D 2 showed a 20% reduction when compared to H 2. • The factors from the Arrhenius equation showed H+ to have greater ease of movement within BCZY compared to D+. • Difference in sensitivity of about 20 % was detected between H 2 and D 2 during amperometric measurements. [ABSTRACT FROM AUTHOR]