Ionics最新文献

Supercapacitors (SCs) have emerged as a promising energy-storage technology, bridging the power and energy density gap between conventional capacitors and batteries. Their high-power density, rapid charge–discharge rates, extended cycle life, and safe operation make them well-suited for next-generation energy applications. Among the materials investigated for SC electrodes, manganese oxide (MnO₂) is particularly promising due to its multiple oxidation states, high theoretical capacitance, and wide operating potential window. This review comprehensively examines recent advancements in MnO₂-based SCs, with an emphasis on MnO₂ composites incorporating carbon materials, conducting polymers (CPs), other transition metal oxides (TMOs), and metal–organic frameworks (MOFs) and covalent organic frameworks (COFs). The synergistic effects and electrochemical performance improvements achieved through these composites are discussed in depth, highlighting strategies for stabilizing MnO₂’s cycling performance and enhancing energy storage through structural integration. Additionally, we address emerging trends and future directions in MnO₂ composite design for SC applications, underscoring their transformative potential for high-performance, scalable energy storage solutions.

Due to the advantages of environmental protection and low cost, aqueous zinc-ion batteries are widely applied in the modern energy storage system. In this study, Cr₂O₃-MnO_x composite material was synthesized via hydrothermal method and further applied as the cathode in aqueous zinc-ion batteries. By optimizing the chromium-to-manganese ratio and the amount of urea, and optimizing the hydrothermal and calcination conditions, the composite material with the best electrochemical performance was obtained. At the current density of 50 mA/g, the maximum capacity reached 384.7 mAh/g, and the cycling stability was also good. The physical characterization of the composite material with the most stable electrochemical performance reveals that its microstructure mainly consists of nanoparticles and nanocubes. The EDS elemental distribution tests show a relatively uniform distribution of manganese, chromium, and oxygen elements. The infrared and Raman spectroscopy indicate the stretching vibrations of Cr–O and Mn–O bonds. The XPS analysis reveals that the primary valence state of Cr is trivalent, while Mn exists in + 2, + 3, and + 4 oxidation states. The quantitative fitting analysis of XRD data shows that Cr₂O₃ is the predominant component.

State-of-health (SOH) is an important indicator for evaluating battery’s performance. However, most of the current data-driven SOH estimation models feature extraction is complex and only applicable to the same type of battery and the same operating conditions. To address this limitation, this paper proposes a multiple measurement health factor extraction method and a transfer learning-convolutional-bidirectional long short-term memory (TL-CNN-BiLSTM) algorithm for SOH evaluation of energy storage batteries. This feature extraction method directly uses the measured values of experimental data as health factors to characterize the degradation characteristics of batteries, which can simplify the calculations. The TL-CNN-BiLSTM algorithm introduces a transfer learning strategy, which learns the general knowledge of battery degradation and fine-tunes the model according to different situations, so that the trained model is suitable for SOH estimation of the different battery under different operating conditions. Using publicly available NASA and CALCE battery datasets for validation, the results show that the extracted multiple measurement features can be used for SOH estimation, and the proposed TL-CNN-BiLSTM algorithm can improve the accuracy of SOH estimation. The root mean square error (RMSE) and mean absolute error (MAE) of the transfer model results between different cells are less than 1%. In addition, the proposed algorithm also performs well in SOH evaluation across data domains.

The rapid capacity loss suffered by P2-type Ni/Fe/Mn-based layered cathode materials, which is caused by deleterious high-voltage phase transformations and the dissolution of active materials, greatly limits their application in large-scale sodium-ion battery installations. In this study, a novel P2/O3 biphasic Na_0.62Mg_0.05Ni_0.15Fe_0.2Li_0.05Mn_0.6O₂ (NM-NFLM) layered cathode is developed using a multi-element (Mg and Li) co-substitution strategy. The absence of significant voltage plateaus in the charge/discharge profiles of cells featuring the proposed cathode indicates that deleterious phase transformations and concomitant lattice mismatch in the high-voltage region are effectively suppressed because of the intergrown structure of the resulting cathode, which has also been demonstrated by ex-situ X-ray diffraction analyses. The optimized cathode also displays improved structural stability and enhanced Na⁺ diffusion kinetics owing to the incorporation of stabilizing dopant pillars. Hence, the assembled Na half-cell delivers a high initial capacity of 205.6 mAh g⁻¹ at 0.1 C and excellent rate capability (98.6 mAh g⁻¹ at 10 C). Moreover, the P2 phase of NM-NFLM is maintained throughout the charging and discharging processes, with only a small amount of the O3 phase undergoing reversible phase transitions of O3-P3-O3, which improves its structure stability significantly. This study presents a design and optimization strategy of high-performance Ni/Fe/Mn-based cathodes.

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Novel, proton-conducting bio-membranes based on Ocimum sanctum leaf (known as holy basil) as a host material and various concentrations of ammonium formate (NH₄HCO₂) have been developed using the solution casting technique. The developed electrolytes are characterized by X-ray diffraction technique (XRD), differential scanning calorimetry (DSC), field emission scanning electron microscope (FESEM), thermo-gravimetric analysis (TGA), impedance spectroscopy, and linear sweep voltammetry (LSV) techniques. As per XRD analysis, a bio-membrane of 1 g of pure Ocimum sanctum with 0.9 M.wt% of ammonium formate shows a very high amorphous nature. The pore size of the highest proton-conducting bio-membranes (0.9 M.wt% of NH₄HCO₂) is found to be in the range of 1.079 to 4.392 μm, using FESEM. The thermal and chemical stability have been analyzed using thermo-gravimetric analysis (TGA). The biomaterial membrane 1 g of pure Ocimum sanctum (OS) with 0.9 M.wt% of ammonium formate has got highest proton conductivity of 7.21 ± 0.03 × 10⁻³ S.cm⁻¹. The electrochemical stability of the highest proton-conducting membrane is found to be 2.36 V (LSV technique). A proton battery has been constructed using the highest proton-conducting membrane as an electrolyte. The constructed proton battery shows an open-circuit voltage of 1.84 V. The stability of the battery has been observed for 50 h. A proton-conducting membrane fuel cell (PEMFC) has been constructed using the highest-conducting proton membrane. The constructed fuel cell shows an open-circuit voltage of 652 mV. The performance of membrane fuel cell (PEMFC) has been studied using different loads.

Aluminum chloride and triethylamine hydrochloride were employed in the synthesis of an AlCl₃-Et₃NHCl electrolyte. An aluminum sheet was utilized as the anode for the electrodeposition of metallic aluminum onto a copper substrate. This study aimed to investigate the effects of deposition potential on the morphology of the aluminum coating, the deposition mechanism, and the changes in Al(III) complex ions during the electrodeposition process. The results indicated that a deposition potential of − 0.3 V (vs. Al) produced aluminum coatings that were uniformly dense and securely adhered to the substrate. When electrodeposition occurred at − 0.5 V (vs. Al), the substrate surface exhibited aluminum nanowires with an approximate diameter of 367 nm. XRD analysis indicated a more pronounced (200) preferred orientation in the aluminum layer deposited at more negative potentials. Raman spectroscopy analysis detected the presence of AlCl₄⁻ and Al₂Cl₇⁻ anions in the AlCl₃-Et₃NHCl system before electrodeposition, followed by the formation of Al₃Cl₁₀⁻ complex ions in the system under potentiostatic control.

Due to their high storage capacity, excellent stability, and strong reversibility, supercapacitors are a major focus in current research and development. For a supercapacitor to exhibit these qualities, an effective electrode material is essential. This review explores the synthesis of electrodes using a composite of polypyrrole (Ppy), reduced graphene oxide (rGO), and nickel–cobalt ferrite (Ni-Co ferrite) for supercapacitor applications. The ternary composite exhibits a high specific capacitance of 250 F/g, outperforming binary composites like rGO/MnFe₂O₄, which typically achieve a specific capacitance of 147 F/g. Polypyrrole amorphous structure offers ideal voids for charge storage, while the plate-like rGO enhances charge accumulation. The magnetic nature of Ni-Co ferrite further contributes multifunctional properties, enabling applications in microwave absorption and toxic gas sensing for industrial gases like NH₃ and CO. These characteristics make the PPy/rGO/Ni-Co ferrite composite highly suitable for advanced energy storage, environmental monitoring, and flexible electronics applications.

In this work, the effect of high energy ball milling (HEBM) on the density and conductive properties of as-prepared Li_1.3Al_0.3Ti_1.7(PO₄)₃ (LATP) solid ceramic electrolyte has been demonstrated. It has been shown that the composition of the LATP phase remains unchanged after HEBM. A gradual decrease in the average crystallite size was observed during the HEBM duration. The multimodal particle size distribution in HEBM samples has a positive effect on their densification during pressing, allowing the use of low pressure (~ 5 MPa). High-density LATP ceramics (~ 89% of the theoretical value) with an ionic conductivity of 2.15∙10⁻⁴ S∙cm⁻¹ were obtained after 30 min of HEBM. The value of electronic conductivity obtained by the analysis of DC polarization using blocking Ag electrodes is equal to 8.3∙10⁻⁹ S∙cm⁻¹. The HEBM approach is accessible and easy to implement. This method does not require high pressure, long sintering temperature and/or time, and additional reagents such as fusible additives. The use of HEBM allows the density and ionic conductivity of the resulting ceramics to be adjusted.

Because of high energy density and Co-free, spinel LiNi_0.5Mn_1.5O₄ materials are considered as potential replacement for availably commercial cathodes like LiNi_xMn_yCo_zO₂ (x + y + z = 1) and LiFePO₄. However, the corrosion and interfacial breakdown of electrolyte at high voltage severely limit the extensive application of LiNi_0.5Mn_1.5O₄. In this paper, LiNbO₃ was used as cladding for LiNi_0.5Mn_1.5O₄ cathode material by convenient and feasible wet-chemical technique. The introduction of Nb⁵⁺ into spinel structure usually replaces Mn ions at octahedral site, thus increasing the content of Mn³⁺. Improve the electronic transition channel and electronic transition carrier of LiNi_0.5Mn_1.5O₄ materials. Therefore, while LiNbO₃ cladding layer protects materials from HF attack, the subsurface-rich Mn³⁺ is considered to boost high-rate performance. When the mass ratio of LiNbO₃ coating is 3%, the coating-modified LiNi_0.5Mn_1.5O₄ material exhibits the best property. The specific discharge capacity was 129.2 mAh·g⁻¹ with 93.5% capacity retention rate after 100 cycles at 1 C, the specific discharge capacity reached 116.0 mAh·g⁻¹ at 5 C. Compared with uncoated LiNi_0.5Mn_1.5O₄ material, it shows outstanding electrochemical properties.