Ionics最新文献

Na₃V₂(PO₄)₂F₃ (NVPF) with sodium superionic conductor NASICON) structure’s quick diffusion channel, high energy density, and high operating voltage make it among the most promising cathode materials for batteries that use sodium ions. But its inadequate inherent electronic conductivity and structural stability hinder its excellent electrochemical performance. In this investigation, N and S co-doped Ketjen Black (NSKB) decorated NVPF cathode material (NVPF@NSKB) was effectively produced using a straightforward sol–gel technique. When NSKB is added, NVPF takes on a loose, porous shape. Improving the conductivity of the material, significantly increasing the contact area between the electrode and the electrolyte, helps the material to perform better electrochemical performance. Compared with the original NVPF@C, NVPF@NSKB shows better charging performance, reaching a capacity of 115.4 mAh g⁻¹ at 0.5 C and 103.3 mAh g⁻¹ at 25 C. The battery also demonstrates excellent cycling stability. After 500 cycles at 30 C, the battery’s capacity remained at 80.7 mAh g⁻¹ with minimal capacity loss. This study demonstrates that N and S co-doped KB is an effective strategy to enhance the performance of sodium-ion battery cathode materials, Na₃V₂(PO₄)₂F₃.

High ionic conductivity polymer electrolytes are now of considerable interest due to their prospective uses in several electrochemical devices such as batteries, fuel cells, solar cells, and supercapacitors. Several approaches have been used to improve their ionic conductivity, including adding plasticizers, polymer blends, and nanocomposites. This work examined how the plasticizer D-sorbitol affected the ion transport in solid polymer electrolyte membranes made of polyvinyl alcohol (PVA) complexed with 30 wt% of LiI. The membranes were created with a D-sorbitol concentration of up to 55 wt% using the solution casting technique. The XRD structural study showed that the membranes’ amorphousness increased when the sorbitol content increased. The complexation between PVA and the additives was studied using UV–vis and FTIR analysis. Electric methods such as ac-impedance spectroscopy and linear sweep voltammetry were used to investigate the conductivity, decomposition voltage, ion transference number, dielectric constant (ε′), dielectric loss factor (ε″), and electric modulus (M) of the investigated membranes. The results indicated the interactions between LiI, PVA, and D-sorbitol plasticizer. The increase in D-sorbitol concentration affected the electrical properties and electrochemical stability window. The highest ionic transfer number value of 0.997 was obtained with 55 wt% of D-sorbitol at 30 °C. The UV–vis optical study revealed a direct allowed transition band with an optical energy gap decreased from 3.92 eV (for PL) to 3.82 eV (for PLS5).

Accurate and robust state of charge (SOC) estimation for lithium-ion batteries is crucial for battery management systems. In this study, we proposed an SOC estimation approach for lithium-ion batteries that integrates the gate recurrent unit (GRU) with the unscented Kalman filtering (UKF) algorithm. This integration aims to enhance the robustness of SOC estimation under complex working conditions and varying temperatures. The GRU neural network is employed to establish an offline training model, while the fusion of the UKF online estimation is utilized to obtain smooth SOC estimation results for lithium-ion batteries. This approach realized a closed-loop SOC estimation strategy. The 18,650 and 26,650 LiFePO₄ batteries were selected for experiments conducted under different charging and discharging conditions at operating temperatures of 10℃, 25℃, and 40 °C. The experiment verified the high accuracy and robustness of the proposed GRU and UKF fusion approach, with both the root mean square error (RMSE) and the mean absolute error (MAE) maintained within 1%.

Fuel cell is considered the best candidate power source because of its high energy conversion rate, large capacity, and zero emission. However, noble metal catalysts as a key core material have some problems, such as high cost and poor durability. Therefore, in this paper, the active self-supporting nanoporous Pd–Ag catalysts are successfully formed by cryogenic treatment and one-step dealloying treatment of Al-Pd–Ag ribbons. The surface of the catalyst ligaments shows a certain degree of preferred orientation for high-index facets (220) and (311). The results show that the activity and stability of the catalysts for methanol electrocatalytic oxidation are significantly improved under the synergistic effect of special configuration and promoter Ag. The electrocatalytic activity of the catalysts is about 9.7 and 15.2 times that of commercial Pt/C and commercial Pd/C catalysts, respectively. After 5000 s, the current density of the 1800 rpm-deep2 sample is 382.88 mA·mg⁻¹, which is about 14.1 times and 39.9 times that of commercial Pt/C catalyst and commercial Pd/C catalyst.

Electrode materials are important indicators for evaluating the performance of electrochemical capacitors, and designing nanostructured materials with high specific capacitance and excellent cycling stability performance is an important way to enhance the performance of supercapacitors. In this study, cetyltrimethylammonium bromide (CTAB) was used as a cationic surfactant, and flower cluster-like Mn₃O₄ particles were prepared by the vesicle soft template method, and different concentrations of CTAB were set in order to investigate its effect on the formation and electrical properties of Mn₃O₄ nanoparticles. Physical and electrochemical characterization was carried out using various means such as XRD, SEM, TEM, BET, CV, EIS, and GCD. The results show that the Mn₃O₄ electrode material exhibits a higher specific capacitance of 261 F/g in 1 M Na₂SO₄ electrolyte when the current density is 0.5 A/g and still maintains 253 F/g when the current density is increased to 10 A/g. Excellent capacitance retention is observed after 10,000 cycles at a current density of 5 A/g (up to 93%). In addition, a Mn₃O₄//AC asymmetric supercapacitor (ASC) was assembled using Mn₃O₄ as the positive electrode and commercially available activated carbon (AC) as the negative electrode, and the device provided a maximum energy density of 30.56 Wh/kg at 452.74 W/kg.

K-carrageenan and various concentrations of zinc nitrate hexahydrate have been combined to develop a zinc ion-conducting biopolymer electrolyte membrane using the solution casting method. To examine the amorphous nature of the samples, X-ray diffraction (XRD) study has been used. The maximum amorphous nature is observed for 1 g K-carrageenan with 1.1 M. wt % of zinc nitrate hexahydrate biopolymer membrane. Fourier transform infrared spectroscopy (FTIR) investigations have shown that the complexation occurs between the K-carrageenan with zinc nitrate hexahydrate. Surface morphology of Pure K-carrageenan, 1 g K-carrageenan with 1.1 M.wt % of zinc nitrate hexahydrate and 1 g K-carrageenan with 1.2 M.wt % of zinc nitrate hexahydrate have been studied by SEM analysis. Pure K-carrageenan membrane (SEM) has uniform surface with uniform small pores. 1 g K-carrageenan with 1.1 M.wt % of zinc nitrate hexahydrate membrane (SEM) shows rectangular rod-shaped nature along with pores of moderate diameter. 1 g K-carrageenan with 1.2 M.wt % of zinc nitrate hexahydrate membrane SEM shows rectangular rod-shaped nature along with pores of moderate diameter and aggregates. For the zinc-doped biopolymer membrane samples, the differential scanning calorimetry (DSC) is used to determine the glass transition temperature. Pure K-carrageenan has got T_g value at 37.04 °C. When the salt concentration is increased upto 0.9 M.wt % of the T_g value increases. When the salt concentration is further increased upto 1.1 M.wt % of the T_g value decreases. Highest zinc ion conducting membrane has got a T_g value of 75.95 °C. According to electrochemical impedance spectroscopy (EIS), the 1 g K-carrageenan with 1.1 M. wt % of zinc nitrate hexahydrate membrane has highest zinc ion conductivity of 2.9 × 10⁻³ S cm⁻¹. According to the linear sweep voltammetry (LSV) investigation, the 1 g K-carrageenan with 1.1 M. wt % of zinc nitrate hexahydrate membrane has shown a wide electrochemical stability window of 2.75 V. The Evans polarization method determined that Zn²⁺ ion has a transference number of 0.42. The cyclic stability of highest conducting biopolymer membrane (Zn²⁺ ion) is studied by Cyclic Voltammetry. The electrolyte used in the construction of the primary zinc battery is 1 g K-carrageenan with 1.1 M. wt % of zinc nitrate hexahydrate having highest zinc ion conductivity. For this built-in battery, the OCV (Open Circuit Voltage) is found to be 1.43 V.