Journal of Solid State Electrochemistry最新文献

Building upon the Na_0.5Bi_0.49-xCa_xTi_0.99Mg_0.01O_3-δ system previously reported for its optimal electrical performance, we synthesized a series of calcium-doped ceramics with compositions Na_0.5Bi_0.49-xCa_x- Ti_0.99Mg_0.01O_3-δ (x = 0, 0.01, 0.02, 0.03) using the solid-phase method. The ceramics underwent precisely controlled two-step thermal processing: initial calcination at 800 °C followed by sintering at 1000 °C, with rigorous stoichiometric control maintained across all samples. The samples were characterized by XRD, SEM, and AC impedance spectroscopy to study the effect of Ca²⁺ doping concentration on the crystal structure, morphology and electrical properties of samples, specially, the bulk conductivity ((sigma_b)), grain boundaries conductivity ((sigma gb)), and total conductivity ((sigma_{t})), which obtained by the fitted impedance spectra, were analyzed in detail to reveal the effect of Ca²⁺-doping on the electrical performance. The findings revealed that all the samples displayed a pure perovskite phase without discernible impurity peaks. Furthermore, the average grain size of the samples decreased as the doping concentration was increased, suggesting that Ca²⁺ play a role in retarding grain growth. Upon substitution of Bi³⁺ with Ca²⁺, the grain conductivity peaked at a doping ratio of x = 0.02. The grain boundary conductivity, on the other hand, increased initially with the rise in x before declining, reaching its maximum at x = 0.01. Consequently, the total conductivity was found to be at its highest when x = 0.01.

One of the key challenges in alkaline direct ethanol fuel cells (ADEFCs) is the sluggish kinetics of the anodic ethanol oxidation reaction (EOR) process. While mono-, bi-, and trimetallic catalysts have been employed to address this issue, high-entropy materials (HEMs) have attracted much attention as EOR electrocatalysts. Due to their multi-elemental compositions and unique high-entropy mixing states, HEMs offer tunable electrocatalytic activity and enhanced stability. These attributes arise from their intriguing quadruple effects: high entropy, lattice distortion, cocktail effect, and sluggish diffusion. Herein, we demonstrate, for the first time, the use of a high-entropy spinel oxide (CuMnFeNiCo)₃O₄, denoted HESOx, uniquely synthesized using a modified Pechini method for the electrocatalytic EOR. The HESOx was decorated with palladium nanoparticles with Vulcan carbon as a support to form Pd-HESOx/C electrocatalyst. After spectroscopic and microscopic characterization, the material was tested for EOR and showcased excellent electroactivity with a mass activity of 3486.5 mAcm⁻¹_Pd, outperforming the commercial counterpart Pd/C (2 224.8 mAcm⁻¹_Pd) at a lower onset potential. The material also demonstrated excellent durability, retaining mass activity above 90% after 500 cyclic voltammetry scans and higher residual mass activity after 4 h of chronoamperometry. Density functional calculations revealed that Pd-HESOx/C reduces the energy barriers for both C–C bond cleavage and C–O coupling while facilitating easier removal of poisonous CO. Overall, the results indicate that Pd-HESOx/C holds promise to serve as a high-performing and durable anode material for alkaline direct ethanol fuel cells.

Graphical Abstract

The pursuit of higher energy density in lithium-ion batteries (LIBs) often pushes safety limits, primarily due to the flammability of liquid electrolytes, which poses significant hazards. This study presents an in situ curing process for the fabrication of high-density pouch cells with gel electrolyte. The electrochemical performance of these pouch cells was evaluated using galvanostatic charge/discharge, electrochemical impedance spectroscopy (EIS), linear voltammetry, and hot box tests. The results show that the electrochemical performance of Ni-rich/silicon-graphite pouch cells with gel electrolyte is comparable to that of pouch cells with traditional liquid electrolyte. After 500 cycles, the pouch cells with gel electrolyte retained 87.59% residual capacity retention, outperforming the 85.40% retention observed in pouch cells with liquid electrolyte. Additionally, the gel electrolyte significantly enhanced the thermal stability of the pouch cells, delaying the thermal runaway by approximately 25 minutes during the 180 °C hot box test. These findings provide valuable insights for the further application and development of high specific energy batteries.

The present work describes the development of a novel photoelectrochemical platform based on bismuth titanate and bismuth oxyiodide (BiOI) for low potential determination of 3-(3,4-dihydroxyphenyl)-L-alanine (DHLA). Herein, Bi₄Ti₃O₁₂ (BIT) and Bi₁₂TiO₂₀ (BTO) were combined with BiOI in order to find the more photoelectroactive material for DHLA. The morphological, spectroscopic, structural, and electrochemical characteristics of the materials were investigated by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), electrochemical impedance, UV–visible diffuse reflectance, and amperometry. The BIT sample presented plate-like particles, and it was consistent with the presence of orthorhombic Bi₄Ti₃O₁₂, while the BTO presented irregular noddle-like particles, and it was consistent with cubic Bi₁₂TiO₂₀. The photoelectrochemical measurements showed that the samples based on Bi₁₂TiO₂₀ presented higher photoactivity than those based on Bi₄Ti₃O₁₂. After evaluating the most photoelectroactive bismuth titanate, a fluorine-doped tin oxide glass slide (FTO) was modified with the Bi₁₂TiO₂₀-based bismuth titanate and bismuth oxyiodide composite (BiOI/BTO/FTO) and applied for the detection of the 3,4-dihydroxy-L-phenylalanine molecule. Under optimized conditions, the BiOI/BTO/FTO photoelectrochemical platform presented a linear response range from 12.7 to 316.9 µmol L⁻¹. The BiOI/BTO/FTO platform was successfully applied to a drug sample with recovery values ranging from 98.14 to 103.88%.

This paper presents a voltammetric method for the electrochemical determination of chloramphenicol (CAP) using a carbon paste electrode modified with graphitic carbon nitride (g-C₃N₄/CPE). CAP is a broad-spectrum antibiotic that has often been identified as a contaminant in environmental and food samples. The modifier (g-C₃N₄) was synthesized via the thermal polycondensation of melamine; a temperature of 650 °C was determined to be optimum as it enhanced the analytical signal and altered the reduction potential of CAP. Electrochemical characterization was performed using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and square-wave voltammetry (SWV). Under optimal conditions, the sensor demonstrated a linear dynamic response ranging from 1.00 × 10⁻⁷ to 4.18 × 10⁻⁶ mol L⁻¹ with a detection limit of 7.91 × 10⁻⁸ mol L⁻¹ in Britton‒Robinson buffer (0.04 mol L⁻¹, pH = 7.00). This approach resulted in remarkable precision, with relative standard deviations (RSDs) of 2.0% for repeatability and 8.0% for reproducibility. The proposed method was effectively used for CAP quantification in milk and water samples, thereby underscoring its dependability and potential for environmental and food safety surveillance.

Thermo-electromotive force (thermo-EMF) of Pd–Ag, Rh-Ag, Pt–Ag and Ag-C couples was measured in temperature range 45.5—715.2 ºC at the cold end temperature of 25 ºC. A cold-end temperature of 25 °C proved to be the most convenient and stable in the following electrochemical experiments. All measurements were carried out by Autolab PGSTAT 302N potentiostat/galvanostat with using the chronopotentiometry method. Thermo-EMF values of Pd–Ag, Rh-Ag, Pt–Ag and Ag-C couples have the same sign. It leads to additive effect for these values for platinoid – C couple and enlarged shift to negative side value of electrode potentials up to 20 mV in electrochemical experiments. These data were used for correction of thermodynamic data on noble metal chloride formation in low-temperature LiCl–KCl-CsCl melt. When thermo-EMF is taken into account, formal electrode potentials have a shift of values up to 10 mV. Recalculation of ∆G*, ∆H*, ∆S* also demonstrates the shift of its values up to 2 kJ·mol⁻¹, 3 kJ·mol⁻¹ and 7 J·mol⁻¹·K⁻¹, correspondingly. These are important changes for building the mathematical model of platinoid separation process in low-temperature LiCl–KCl-CsCl melt at working temperature of 450 ºC.

Symmetrical solid oxide fuel cells (S-SOFCs) are energy-efficient electrochemical power sources that open up new possibilities for clean energy. In this work, the physicochemical properties of fluorite-like Nd₅Mo₃O_16+δ (NMO) have been investigated for the first time to evaluate its potential as an electrode material for S-SOFC. Electrical conductivity measurements under reducing conditions (Ar/H₂) at 100–900 °C have revealed thermally activated behavior with predominant electronic conductivity of 1.7 S/cm at 800 °C. The thermal expansion coefficient of NMO in Ar/H₂ at 25–900 °C has been determined to be 10.7 ppm/K. No new phases formed when NMO was heated with conventional electrolyte materials up to 950 °C with Ce_0.9Gd_0.1O_1.95 (GDC) and 850 °C with Zr_0.84Y_0.16O_1.92 (YSZ). The polarization resistance (R_η) of the NMO electrode at 800 °C has been recorded as 15.1 Ω·cm² in air and 5.6 Ω·cm² in an Ar/H₂ atmosphere. An electrolyte-supported S-SOFC with the NMO/GDC/YSZ/GDC/NMO configuration has achieved a power density of 14 mW/cm² at 900 °C. Replacing the NMO cathode with (La_0.75Sr_0.25)_0.95MnO_3-δ has led to the increase of the power density to 100 mW/cm² at 900 °C. Long-term stability tests carried out on both fuel cells under a constant voltage of 0.7 V showed no significant degradation in performance. Thus, the obtained results demonstrated that NMO is a promising candidate for use as an anode material in SOFCs.