Journal of Power Sources最新文献

Temperature fluctuations impact battery performance, safety, and health. Industry-standard cell-level models of these phenomena ignore thermal gradients within the electrodes’ active material, i.e., assume the latter to be in “thermal equilibrium”. We present a “non-equilibrium” thermal model that explicitly accounts for spatial variability of temperature with the active material (and the carbon-binder domain). We investigate the conditions, expressed in terms of the heat-generation rate and the thermal properties of a cell’s liquid (electrolyte) and solid (active material and CBD) phases, under which the thermal equilibrium assumption breaks down and our model should be used instead. The differences between these two thermal models are investigated further by coupling them with an industry-standard electrochemical model. The resulting thermal–electrochemical model demonstrates the importance of thermal gradients within the active material at high C-rates (discharge current densities) and for large grain sizes. Under these conditions, the equilibrium assumption underestimates internal temperature by as much as 50%. These two thermal models are then applied to a commercial NMC battery with multiple units. Our non-equilibrium model predicts the battery surface temperature that is in good agreement with measurements, while the equilibrium model underestimates the observed temperature.

Due to their excellent high Faraday efficiency, perovskite solid oxide cells (SOECs) have attracted considerable attention. Nevertheless, they still face significant challenges in terms of stability and electrocatalytic activity during CO₂ electrolysis. In this study, Ni particles in La_0.65Ba_0.35Mn_1-xNi_xO_3-δ are successfully separated by a unique in-situ exsolved method of metal nanoparticles, which are uniformly anchored to the electrode surface as Ni nanometal particles. This effectively suppresses the generation of carbon deposits on the cathode surface. Under test conditions of 850 °C, 1.6 V and 50 sccm flow rate, the CO yield of the modified cathode material reached 5.9 mL min⁻¹ cm⁻², which is nearly four times higher than that before doping. The synergistic effect of in-situ exsolution of Ni metal nanoparticles with oxygen defects generated by the perovskite, creating more active locations for CO₂ adsorption and electrolysis, is responsible for the significant improvement in electrochemical performance. This work provides new strategies and ideas for the development of efficient and durable SOEC cathode materials.

Accurate state of charge (SOC) estimation is essential for battery safe and efficient utilization. As artificial intelligence technologies evolve, data-driven methods have become mainstream for estimating SOC. However, the technique can significantly deteriorate model performance when encountering poor or insufficient data quality. In this paper, we apply median filtering to eliminate extreme noise and utilize continuous wavelet transform to extract time-frequency features from voltage signals. Additionally, we generate novel features via feature crossing. We then apply dimensionality reduction via the random forest method to decrease computational expense. Finally, we select a convolutional neural network (CNN) as the base model to learn optimized features for more precise SOC estimation. To confirm the efficacy of our proposed method, this study compares it with CNN, long short-term memory (LSTM), bidirectional LSTM (BILSTM), and a CNN-BILSTM model combined with an attention mechanism. These comparisons are conducted under different temperatures and operating conditions. The results indicate that this method achieves a mean absolute error and a root mean square error of less than 2.89 % and 3.71 %, respectively, in SOC estimation, demonstrating superior accuracy compared to other models. This study underscores the significance of feature engineering techniques in SOC estimation.

The superior performance enhancement in catalyst research for proton exchange membrane fuel cells (PEMFC) revealed in the model rotating disc electrode (RDE) environment is rarely demonstrated in membrane electrode assemblies (MEA). The discrepancy is typically attributed to the difference in the chemical structure and morphology of the catalyst layer (CL), affecting the transport of reactants of the oxygen reduction reaction (ORR). In this study, the gas diffusion electrode (GDE) half-cell setup is used to focus on crucial aspects of CL development, especially on the activation and morphology of CLs, to gain a fundamental understanding of the development of PEMFCs. Adjusting the CL porosity by using different solvent compositions of water and isopropyl alcohol and implementing an activation method for low platinum content catalysts, we focus on understanding the contributions of macro-porosity and hydrophobicity in a liquid electrolyte-based system. We show that macro-porosity significantly influences the O₂ mass transport in the CL, demonstrating increased performance with higher porosities. Coupling inductively coupled plasma mass spectrometry (ICP-MS) with the GDE half-cell setup, we propose a method for qualitative estimation of water content in the CL. Lower macro-porosity shows higher platinum dissolution, attributed to improved mass transport of dissolved ions in aqueous media.

The performance of Li-O₂ battery can be improved by adjusting the reaction active sites of cathode catalysts. In this study, noble metal ruthenium (Ru) was successfully added to the framework of Zeolitic Imidazolate Framework-67 (ZIF-67) through a dual solvent method, and prepared highly dispersed noble metal ruthenium cathode catalyst material for Li-O₂ battery. At the same time, the phenomenon of aggregation of precious metal ruthenium on the catalyst surface is avoided, and the atomic utilization rate of precious metals is improved. The low crystallinity cobalt oxide (ZIF-67-280) and noble metal ruthenium act as the catalytic active center together, enriching the reaction active sites of the catalyst, further improving the performance of Li-O₂ battery and reducing the reaction overpotential. Compared to commercial cobalt oxides (C-Co₃O₄), ruthenium doped low crystallinity cobalt oxides (Ru@ZIF-67-280) has better cycle stability (272 cycles) and higher energy efficiency.

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Potassium-ion batteries (PIBs) could be a cheaper and more abundant alternative to lithium-ion batteries, offering faster charging and suitability for large-scale energy storage. Prussian blue (PB) is prepared through a simple wet chemical method, and its intercalation affinity for K⁺ ions is tested using linear sweep voltammetry (LSV). The diffusion resistance (R_w: ∼116 Ω Hz^1/2) and low-frequency region slope (m: ∼0.63) are found high for the third LSV drive (Seg-3), indicating passivation of the PB surface which leads to a double-layer formation. Most of the K⁺ ions are intercalated into PB until three LSV segments. After that PB surface is passivated and prohibits further LSV-driven K⁺ ions intercalation. On average, the Seg-3 sample exhibits a 58 % higher lattice strain in comparison to the as-prepared PB. A capacity of 27 mAh g⁻¹ @ 2 mA g⁻¹ in aqueous media is recorded for the Seg-3 sample and a capacity drop of 4 mAh g⁻¹ and Coulombic efficiency of 99.3 % is recorded under 100 cycles. These findings are further comprehensively validated through multi-technique approaches. The observed affinity and single-stage LSV-driven intercalation of K⁺ ions highlight the perspective of PB as an electrode material for aqueous potassium ion batteries (a-PIBs).

All-solid-state lithium-ion batteries that employ Si negative electrodes are the most promising candidates for next-generation batteries because of their high safety performance and energy density. However, the contact between Si and the solid electrolyte becomes insufficient because of the volume changes of Si associated with charging and discharging, resulting in a significant drop in battery performance. Although mechanical milling forms good interparticle contacts, the reaction between Si and a sulfide solid electrolyte increases the resistance, thereby decreasing battery performance. Therefore, in this study, we investigated the effects of the mechanochemical reactions between several solid electrolytes and Si on battery performance. A decrease in electronic conductivity was observed from the reaction between Si and sulfide or oxide solid electrolytes, whereas no significant decrease was observed with halide solid electrolytes. Consequently, an Si composite electrode constructed with a halide solid electrolyte showed high reversibility, achieving a high area capacity of 4.6 mA h cm⁻² and specific energy density of 470 Wh kg⁻¹ (masses of positive and negative composite electrodes) in a full-battery cell with an Li₂S positive composite electrode at 0.25 mA cm⁻² and 25 °C. The study contributes to understanding the important factors in the advancement of all-solid-state lithium-ion batteries.

The flow battery represents a highly promising energy storage technology for the large-scale utilization of environmentally friendly renewable energy sources. However, the increasing discharge power of rechargeable battery results in a higher charge voltage due to its coupling relationship in charge-discharge processes, intensifying the burden of renewable energy power systems. Herein, we proposed a voltage-decoupled Na⁺-conducting Zn-Br₂ flow battery (U_d-Na-ZBFB). Within a pH-regulation strategy, both neutral Zn/Zn²⁺ and alkaline Zn/Zn(OH)₄²⁻ negative redox couples are integrated into one device, so as to increase discharge voltage a 0.5 V theoretical increase while remains a low charge voltage. The proof-of-concept U_d-Na-ZBFB demonstrates an unprecedented voltage characteristic, achieving a discharge voltage of up to 2.18 V while maintaining a remarkably low charge voltage of 1.78 V at a current density of 20 mA cm⁻². Benefiting from the high discharge voltage, the peak power density of U_d-Na-ZBFB reaches 580 mW cm⁻², nearly twice higher than the traditional ZBFB. Besides, the U_d-Na-ZBFB cycling operates for 45 h with excellent stability and resilience. With the “cycle-to-stage” operational mode, battery state of U_d-Na-ZBFB can be completely recovered after a long-term operation stage with several cycles, which electrolyte utilization efficiency of one stage is up to 41 %. This work offers a brand-new utilization pattern for high-power rechargeable battery that possesses a great potential in energy storage application scenes.

Reasonably designing and constructing transition metal based compounds with controllable composition and structure is a promising option for obtaining economically efficient oxygen evolution reaction (OER) electrocatalysts. This paper presents a one-pot self-templated epitaxial growth, phase transition and self-dissolution strategy for constructing hollow nanoboxes/solid nanocubes of CoFe bimetallic Prussian blue analogues (PBAs). The CoFe mixed phosphide with a porous hollow nanoboxes structure obtained after subsequent phosphating heat treatment exhibite enhanced OER electrocatalytic activity in alkaline media, exhibiting a low overpotential of 230 mV and a Tafel slope of 35.5 dec⁻¹ at 10 mA cm⁻², as well as excellent stability for 48 h. The excellent OER activity of CoP-FeP nanoboxes (CoP-FeP NBs) can be attributed to the combination effect between their composition and structure. Structurally, the exquisite porous hollow nanoboxes structure greatly expands the surface area, reduces ion diffusion pathways, and reduces charge transfer resistance. Compositionally, the inner transition metal phosphide exhibits good conductivity and undergoes surface reconstruction during OER, forming high valence Co(Fe)OOH active substances in situ. The strong interface coupling effect of CoOOH/FeOOH optimizes the electronic structure. This work presents a facile and efficient strategy for the construction of PBAs hollow structural materials and the exploitation of low-cost and efficient electrocatalysts.

The emerging dual-ion batteries are a sustainable analog of conventional Lithium-ion batteries. It yields high voltage output and satisfying capacity, replacing transition metal-based cathodes with graphitic carbon. Despite the advantages, the systems suffer from inadequate cycling efficiencies and triggered electrolyte decomposition on cathode surface that cut short the cycle life. As a protective measure, the carbon cathode is coated using a LiF/Li_xPO_y/Li_xPO_yF_z-based hybrid coating layer derived from the thermal decomposition of LiPF₆ salt. The coated layer acts as an artificial interface that safeguards the surface from electrolyte attack and enhances cycling efficiencies. It forms a mechanochemically robust cathode-electrolyte interface that preserves the graphitic order and structural integrity of the electrode. As a result, the bulk of the coated material is not ruptured like in the uncoated pristine sample, thereby assisting in long-term cycling. The coated material retains 85 % capacity even after 1000 cycles with a 10 % improved coulombic efficiency and 130 mV reduced voltage hysteresis instead of losing 15 % capacity within 50 cycles with poor efficiency and elevated resistances in the pristine material. The strategy brings fruitful outcomes when applied in dual carbon cell and is believed to be equally effective in other dual-ion systems.