Search Results (28)

Traditional liquid electrolyte batteries face safety concerns such as leakage and flammability, while further optimization has reached a bottleneck. Solid electrolytes are therefore considered a promising solution. Here, a PEO–LiTFSI–LATP (PELT) composite electrolyte was developed by incorporating nanosized Li_1.3Al_0.3Ti_1.7(PO₄)₃ fillers into a polyethylene oxide matrix, effectively reducing crystallinity, enhancing mechanical robustness, and providing additional Li⁺ transport channels. The PELT electrolyte exhibited an electrochemical stability window of 4.9 V, an ionic conductivity of 1.2 × 10⁻⁴ S·cm⁻¹ at 60 °C, and a Li⁺ transference number (tLi+) of 0.46, supporting stable Li plating/stripping for over 600 h in symmetric batteries. More importantly, to address poor electrode–electrolyte contact in conventional layered cells, we proposed an integrated electrode–electrolyte architecture by in situ coating the PELT precursor directly onto LiFePO₄ cathodes. This design minimized interfacial impedance, improved ion transport, and enhanced electrochemical stability. The integrated PELT/LFP battery retained 74% of its capacity after 200 cycles at 1 A·g⁻¹ and showed superior rate capability compared with sandwich-type batteries. These results highlight that coupling LATP-enhanced polymer electrolytes with an integrated architecture is a promising pathway toward high-safety, high-performance solid-state lithium-ion batteries. Full article

In this study, cerium with different ratios (x = 0 (zero), 0.1, 0.15, 0.5) was added to the PrMn structure as an A-site material to evaluate characteristic behavior as a potential cathode material for solid oxide fuel cells. The Pr_xCe_1−xMnO_3−δ electrocatalysts were synthesized using the sol–gel combustion method and were assessed for their electrochemical, phase, and structural properties, as well as desorption and reducibility capabilities. Phase changes, from orthorhombic to cubic structures observed upon cerium additions, were evaluated via the X-Ray diffraction method. X-Ray photoelectron spectroscopy (XPS) showed the valence states of the surface between the Ce⁴⁺/Ce³⁺ and Pr⁴⁺/Pr³⁺ redox pairs, while oxygen temperature programmed desorption (O₂-TPD) analysis was used to evaluate the oxygen adsorption and desorption behavior of the electrocatalysts. Redox characterization, evaluated via hydrogen atmosphere temperature-programmed reduction (H₂-TPR), revealed that a higher cerium ratio in the structure lowered the reduction temperature, suggesting a better dynamic oxygen exchange capability at a lower temperature for the Pr_0.5Ce_0.5MnO_3−δ catalyst compared to the electrochemical behavior analysis by the electrochemical impedance spectroscopy method. Moreover, the symmetrical cell tests with Pr_0.5Ce_0.5MnO_3−δ electrodes showed that, when combined with scandia-stabilized zirconia (ScSZ) electrolyte, the overall polarization resistance was reduced by approximately 28% at 800 °C compared to cells with yttria-stabilized zirconia (YSZ) electrolyte. Full article

Solid oxide fuel cells (SOFCs) have become promising devices for converting chemical energy into electrical energy. Altering the microstructure of cathode materials to enhance the activity and stability of the oxygen reduction reaction is particularly important. Herein, Pr_0.5Ba_0.5Co_1−XNi_XO_3+δ with a tetragonal perovskite structure was synthesized through the sol–gel method. The polarization resistance of the symmetrical half-cell with Pr_0.5Ba_0.5Co_0.9Ni_0.1O_3+δ as the cathode was 0.041 Ω·cm² at 800 °C and 0.118 Ω·cm² lower than that of the symmetrical cell with Pr_0.5Ba_0.5CoO_3+δ as the cathode, indicating that the Pr_0.5Ba_0.5Co_1−XNi_XO_3+δ cathode material had high catalytic activity during the electrochemical reaction. The results of electron paramagnetic resonance revealed that the concentration of oxygen vacancies increased as the Ni doping amount increased to 0.15. As a result of the increase in the Ni doping amount, the thermal expansion coefficient of the Pr_0.5Ba_0.5CoO_3+δ cathode material was effectively reduced, resulting in improved matching between the cathode and electrolyte material. The power density of the single cell increased by 69 mW·cm⁻². Therefore, Pr_0.5Ba_0.5Co_1−XNi_XO_3+δ is a promising candidate cathode material for high-performance SOFCs. Full article

The development of symmetrical solid oxide fuel cells with identical cathode and anode is beneficial for thermal matching and reducing the cost. Herein, proton-conducting electrolyte and novel high catalytic activity electrode material for symmetrical solid oxide fuel cells are proposed. Ni-doping at the B-site of (Sr_0.8Ce_0.2)_0.95FeO_3−δ (SCF) indicates reduced cell edge lengths, cell volume, and a more porous honeycomb structure. The B-site elements in oxide tend to have a high oxidation state via Ni-doping. Simple doping modification in SCF causes better thermal matching between the electrode and electrolyte and form more oxygen vacancies at the operating temperature. At the anode side, Ni-doping improves the stability of the symmetric electrode in reducing the atmosphere. The polarization resistance of symmetrical cells for new electrode material is half of the original both in oxidation and reduction atmosphere, which indicates boosted electrochemical performance for the cathode and anode. At the same time, Ni-doping reduces the impedance activation energy of the anode reaction in symmetric cells. The output performance of the cell is 210.4 mW·cm⁻² at 750 °C and the thickness of the electrolyte is 400 μm, achieving a highly efficient symmetrical electrode in proton ceramic fuel cells. The new finding of materials provides a novel high efficiency symmetrical electrode and proposes guidance for the improvement of solid oxide fuel cells at a reduced temperature. Full article

R&D in the area of high-temperature symmetrical electrochemical devices is needed to meet the challenges of hydrogen energy. In the present study, the effect of Fe₂O₃ and CuO sintering aids on the electrochemical properties of the highly conductive solid electrolyte La_0.8Sr_0.2Ga_0.8Mg_0.2O_3−δ and La_0.6Sr_0.4FeO_3−δ electrodes for symmetrical solid oxide fuel cells was investigated. It is shown that the use of sintering aids leads to an improvement in grain boundary conductivity and allows us to reduce the sintering temperature to obtain a dense electrolyte with the same level of conductivity. It is shown for the first time that the nature of the sintering aids and the sintering temperature affect the La_0.6Sr_0.4FeO_3−δ electrode activity differently depending on the gas environment (air or hydrogen). On the basis of the analysis of the impedance spectra by the distribution of relaxation times, assumptions were made about the nature of the rate-determining steps of hydrogen oxidation and oxygen reduction. It is shown that the nature of the rate-determining steps can change depending on the electrode sintering temperature. It was found that among the studied electrodes, La_0.6Sr_0.4FeO₃−_δ with 3 wt.% Fe₂O₃ sintered at 1050 °C is optimal in terms of activity in oxidizing and reducing atmospheres. Full article

Solid-state supercapacitors with gel electrolytes have emerged as a promising field for various energy storage applications, including electronic devices, electric vehicles, and mobile phones. In this study, nanocomposite gel membranes were fabricated using the solution casting method with perfluorosulfonic acid (PFSA) ionomer dispersion, both with and without the incorporation of 10 wt.% montmorillonite (MMT). MMT, a natural clay known for its high surface area and layered structure, is expected to enhance the properties of supercapacitor systems. Manganese oxide, selected for its pseudocapacitive behavior in a neutral electrolyte, was synthesized via direct co-precipitation. The materials underwent structural and morphological characterization. For electrochemical evaluation, a two-electrode Swagelok cell was employed, featuring a carbon xerogel negative electrode, a manganese dioxide positive electrode, and a PFSA polymer membrane serving as both the electrolyte and separator. The membrane was immersed in a 1 M Na₂SO₄ solution before testing. A comprehensive electrochemical analysis of the hybrid cells was conducted and compared with a symmetric carbon/carbon supercapacitor. Cyclic voltammetric curves were recorded, and galvanostatic charge–discharge tests were conducted at various temperatures (20, 40, 60 °C). The hybrid cell with the PFSA/MMT 10 wt.% exhibited the highest specific capacitance and maintained its hybrid profile after prolonged cycling at elevated temperatures, highlighting the potential of the newly developed membrane. Full article

Mixed oxygen ion and electron-conducting materials are viable cathodes for solid oxide fuel cells due to their excellent oxygen transport kinetics and mixed electrical conductivity, which ensure highly efficient operation at low and medium temperatures. However, iron-based double perovskite oxides usually exhibit poor electrocatalytic activity due to low electron and oxygen ion conductivity. In this paper, Ca is doped in PrBaFe₂O_5+δ A-site to improve the electrochemical performance of PrBaFe₂O_5+δ. Results show that replacing Pr with Ca does not change the crystal structure, and the Ca doping effectively increases the adsorbed oxygen content and accelerates the migration and diffusion rate of O²⁻ to the electrolyte|cathode interface. The polarization resistance of the symmetric cell PC_0.15BF|CGO|PC_0.15BF is 0.033 Ω·cm² at 800 °C, which is about 56% lower than that of PBF, confirming the enhancement of the mixed conduction of oxygen ions and electrons. In addition, the anode-supported single cell has a peak power density of 512 mW·cm⁻² at 800 °C. Full article

Solid polymer electrolytes (SPEs) are the key components of lithium metal batteries to overcome the obstacle of insecurity in conventional liquid electrolytes; however, the trade-off between their ionic conductivity and mechanical properties remains a significant challenge. In this work, two-dimensional ZSM-5 nanosheets as fillers are incorporated into a poly(ethylene oxide) (PEO) matrix and lithium salts to obtain composite polymer electrolytes (CPEs). The improved physicochemical and electrochemical properties of the CPE membranes are characterized in full detail. Stripping/plating measurements in symmetric Li/Li cells and cyclic charge/discharge tests are performed to investigate the cyclability and stability of the CPEs. All-solid-state LiFePO₄/Li batteries deliver excellent cycling performance with an initial discharge capacity of 152.3 mAh g⁻¹ and 91.4% capacity retention after 200 cycles at 0.2 C, with a discharge specific capacity of 118.8 mAh g⁻¹ remaining after 350 cycles at 0.5 C. Therefore, CPEs containing ZSM-5 nanosheets are a promising option for all-solid-state lithium-ion batteries. Full article

High ionic conductivity, outstanding mechanical stability, and a wide electrochemical window are the keys to the application of solid-state lithium metal batteries (LMBs). Due to their regular channels for ion transport and tailored functional groups, covalent organic frameworks (COFs) have been applied to solid electrolytes to improve their performance. Herein, we report a flexible polyethylene oxide-COF-LZU1 (abbreviated as PEO-COF) electrolyte membrane with a high lithium ion transference number and satisfactory mechanical strength, allowing for dendrite-free and long-time cycling for LMBs. Benefiting from the interaction between bis(triflfluoromethanesulonyl)imide anions (TFSI⁻) and aldehyde groups in COF-LZU1, the Li⁺ transference number of the PEO-5% COF-LZU1 electrolyte reached up to 0.43, much higher than that of neat PEO electrolyte (0.18). Orderly channels are conducive to the homogenous Li-⁺ deposition, thereby inhibiting the lithium dendrites. The assembled LiFePO₄|PEO-5% COF-LZU1/Li cells delivered a discharge specific capacity of 146 mAh g⁻¹ and displayed a capacity retention of 80% after 200 cycles at 0.1 C (60 °C). The Li/Li symmetrical cells of the PEO-5% COF-LZU1 electrolyte presented a longer working stability at different current densities compared to that of the PEO electrolyte. Therefore, the enhanced comprehensive performance of the solid electrolyte shows potential application prospects for use in LMBs. Full article

Solid-state lithium metal batteries (LMBs) have been extensively investigated owing to their safer and higher energy density. In this work, we prepared a novel elastic solid-state polymer electrolyte based on an in situ-formed elastomer polymer matrix with ion-conductive plasticizer crystal embedded with Li_6.5La₃Zr_1.5Ta_0.5O₁₂ (LLZTO) nanoparticles, denoted as LZT/SN-SPE. The unique structure of LZT/SN-SPE shows excellent elasticity and flexibility, good electrochemical oxidation tolerance, high ionic conductivity, and high Li⁺ transference number. The role of LLZTO filler in suppressing the side reactions between succinonitrile (SN) and the lithium metal anode and propelling the Li⁺ diffusion kinetics can be affirmed. The Li symmetric cells with LZT/SN-SPE cycled stably over 1100 h under a current density of 5 mA cm⁻², and Li||LiFePO₄ cells realized an excellent rate (92.40 mAh g⁻¹ at 5 C) and long-term cycling performance (98.6% retention after 420 cycles at 1 C). Hence, it can provide a promising strategy for achieving high energy density solid-state LMBs. Full article

Transparent ZnMn₂O₄ thin films on indium tin oxide (ITO) were prepared through spray pyrolysis and implemented as electrodes in symmetric supercapacitors (SSCs). A specific capacitance value of 752 F g⁻¹ at 0.5 A g⁻¹ and a 70% retention over 3000 galvanostatic charge–discharge (GCD) cycles were reached with a 1.0 M Na₂SO₄ electrolyte in a three-electrode electrochemical cell. Analysis of the cycled electrodes with 1.0 M Na₂SO₄ revealed a local loss of electrode material; this loss increases when electrodes are used in SCCs. To avoid this drawback, solid polyvinylpyrrolidone-LiClO₄ (PVP-LiClO₄) and quasi-solid polyvinylpyrrolidone-ionic liquid (PVP-ionic liquid) electrolytes were tested in SSCs as substitutes for aqueous Na₂SO₄. An improvement in capacitance retention without a loss of electrode material was observed for the PVP-ionic liquid and PVP-LiClO₄ electrolytes. With these non-aqueous electrolytes, the tetragonal structure of the ZnMn₂O₄ spinel was maintained throughout the cyclic voltammetry (CV) cycles, although changes occurred in the stoichiometry from ZnMn₂O₄ to Mn-rich Zn_1−xMn_3−xO₄. In the case of the electrolyte 1.0 M Na₂SO₄, the loss of Zn²⁺ led to the formation of MnO₂ via Zn_1-xM_3-xO₄. The location of the three SCCs in the Ragone plot shows supercapacitor behavior. The electrochemical results prove that the pseudocapacitance is the major contributor to the electrode capacitance, and the SCCs can therefore be considered as pseudocapacitors. Full article

A new strategy to reduce the operating temperature of the solid oxide fuel cell (SOFC) is needed to foster the progress of developing high-performance and stable SOFC as a solution to the thermal stress and degradation of the cell components induced by high-temperature SOFC. The use of lithium (Li) as a cathode can increase the cell’s efficiency, as it allows for faster ion transport and a higher reaction rate. This study presents an attractive approach to using a Li-based cathode by combining Li with cobalt (Co) to form LiCo_0.6Sr_0.4O₂ (LCSO). In this work, a precursor consisting of Li, Co, and strontium (Sr) was prepared via the glycine-nitrate combustion method. The precursor was calcined at two different calcination temperatures (800 and 900 °C) prior to ink formulation and symmetrical cell fabrication in order to study the effect of calcination temperature on the structural and electrochemical behaviour of a Li-based cathode. The precursor LCSO powder was characterised using X-ray crystallography (XRD) to determine the crystal structure and composition of the developed LCSO. The electrochemical performance of the fabricated symmetrical cell was tested using electrochemical impedance spectroscopy (EIS) to obtain the cell’s resistance information, which is related to the cell’s ionic and electronic conductivity. SDC electrolyte with LCSO calcined at 800 °C has a higher crystallinity percentage and a more porous structure compared to LCSO calcined at 900 °C. The porous structure enhanced the electrochemical performance of the cell, where the symmetrical cell has the highest conductivity (0.038 Scm⁻¹) with the lowest activation energy (0.43 eV). The symmetrical cell was also able to achieve 2.89 Ω cm² of area-specific resistance (ASR) at 800 °C of operating temperature. In conclusion, the SDC electrolyte with LCSO calcined at 800 °C is the promising cathode material for SOFC applications. The result of this study can benefit the SOFC field of research, especially in the development of intermediate temperature-SOFC. Full article

Reversible symmetrical solid oxide cells (RS-SOCs) have attracted much attention due to their high energy conversion efficiency and fabrication simplicity. In this study, 10% Fe was substituted with Ni in the B-site of Sr_0.9Fe_0.9Mo_0.1O_3−δ to enhance the electrochemical performance of H₂O electrolysis. The characterization results and theoretical calculations indicated that Ni doping decreased the adsorption and reaction energy barrier of intermediates of H₂O electrolysis on the Sr_0.95Fe_0.8Mo_0.1Ni_0.1O_3−δ’s (111) surface, which promoted the kinetics of the electrode reaction, thus fabricating electrochemical activity and resulting in higher reaction dynamics. Consequently, a high power density of 1.145 W cm⁻² at 850 °C on a symmetrical cell was achieved in the solid oxide fuel cell (SOFC) mode, and a current density of 3.995 A cm⁻² was obtained at 850 °C and 1.6 V in the solid oxide electrolysis cell (SOEC) mode, indicating the Sr_0.9Fe_0.8Mo_0.1Ni_0.1O_3−δ oxide to be a promising SOFC electrode for power production and SOEC electrode for H₂ production. Full article

Membranes based on complex solid oxides with oxygen-ionic conductivity are widely used in high-temperature electrochemical devices such as fuel cells, electrolyzers, sensors, gas purifiers, etc. The performance of these devices depends on the oxygen-ionic conductivity value of the membrane. Highly conductive complex oxides with the overall composition of (La,Sr)(Ga,Mg)O₃ have regained the attention of researchers in recent years due to the progress in the development of electrochemical devices with symmetrical electrodes. In this research, we studied how the introduction of iron cations into the gallium sublattice in (La,Sr)(Ga,Mg)O₃ affects the fundamental properties of the oxides and the electrochemical performance of cells based on (La,Sr)(Ga,Fe,Mg)O₃. It was found that the introduction of iron leads to an increase in the electrical conductivity and thermal expansion in an oxidizing atmosphere, while no such behavior was observed in a wet hydrogen atmosphere. The introduction of iron into a (La,Sr)(Ga,Mg)O₃ electrolyte leads to an increase in the electrochemical activity of Sr₂Fe_1.5Mo_0.5O_6−δ electrodes in contact with the electrolyte. Fuel cell studies have shown that, in the case of a 550 µm-thick Fe-doped (La,Sr)(Ga,Mg)O₃ supporting electrolyte (Fe content 10 mol.%) and symmetrical Sr₂Fe_1.5Mo_0.5O_6−δ electrodes, the cell exhibits a power density of more than 600 mW/cm² at 800 °C. Full article

This paper examines the electrochemical and microstructural features of SrCo_0.8Fe_0.1Ga_0.1O_3−δ (SCFG) with a fibrous structure infiltrated by an SDC electrolyte for use as a cathode in solid oxide fuel cells (SOFCs). An electrospinning process is used to produce SCFG fibers. In a symmetrical cell, Sm_0.2Ce_0.8O_1.9 (SDC) nanoparticles are infiltrated into the porous fibrous SCFG cathode layer after it was applied to the SDC dense electrolyte. Electrochemical impedance spectroscopy (EIS) analysis reveals that the polarization resistance of the SCFG cathode with fiber morphology is significantly lower than that of the same combination with powder morphology. In addition, it is shown that infiltration of SDC oxygen ion conductor nanoparticles enhanced electrochemical performance. The lowest value of polarization resistance, 0.03 Ω cm² at 800 °C, is attained by the SCFG with a fibrous structure containing 14 wt% SDC nanoparticles. Full article