Journal of Power Sources最新文献

Electrochemical water splitting represents a viable route for hydrogen production, but its efficiency critically depends on developing effective electrocatalysts that minimize energy loss and material costs. This study introduces iridium-cobalt (Ir–Co) nanoparticles were synthesized on copper foam (CF) substrates using a one-step electrodeposition method. A comprehensive analysis was conducted on the morphology, chemical composition, and crystal structure of the electrocatalysts, along with a particular study on their electrocatalytic performance in the hydrogen evolution reaction (HER). The results demonstrate that high-index IrCo (311) crystal planes have been detected in the Ir–Co/CF electrocatalysts, which possess a tetradecahedral polycrystalline structure. The size of tetradecahedral nanoparticles is in the range of 180–250 nm. Ir–Co nanoparticles exhibit a balanced composition of approximately 49.8 at% Ir and 50.2 at% Co. The Ir–Co/CF electrocatalyst exhibits superior electrocatalytic activity in 1.0 M KOH solution, requiring only 46.8 mV overpotential to obtain a current density of 10 mA cm⁻², with a low Tafel slope of 32.65 mV·dec⁻¹. Additionally, the prolonged stability tests confirm the robustness of the Ir–Co/CF electrocatalyst, highlighting its potential for sustainable energy applications.

With the attempts of more than 30 years, the current commercial LiCoO₂ (LCO) offers a reversible capacity of 185 mAh g⁻¹ with a cut-off voltage of 4.5 V vs. Li⁺/Li. Further increasing the cut-off voltage, more lithium-ions can extract, deeply enhancing the capacity and energy density. However, it results in numerous side reactions and a significant decay in battery cycle performance. To address these issues, Nano-LiNbO₃ as a coating agency is introduced by a solid-state surface-to-bulk modification process. To avoid the agglomeration and achieve uneven coating of Nano-LiNbO₃ in the solid-state reaction, polyvinylpyrrolidone (PVP) is introduced as a dispersant, which effectively ensures the uniform and smooth coating along with the carbonization process. The modified LCO sample presents a specific reversible capacity of 215.5 mAh g⁻¹ in the initial cycle and a capacity retention rate of 90 % after 100 cycles at 3–4.6 V and 0.5 C. Further analysis demonstrate that the LiNbO₃ surface coating layer and the element gradient doping layer provide LCO a stable structure and an inert surface, which improves the surface stability, suppresses the oxygen release and ensures the enhanced electrochemical performance.

Enhancing the frequency of traditional supercapacitors to hundreds or thousands of Hz enables them to replace bulky aluminum electrolytic capacitors for line filtering and function as storage device for the harnessed ambient noise energy for powering the distributed sensor networks and IoT. This work reports a kHz frequency-capable pseudocapacitor comprising electrodes with anatase nanotube arrays (NTA). NTA are grown in-situ via anodization of a titanium foil, providing excellent electrical contact with the underlying unconverted titanium foil. The use of an organic electrolyte (glycerol and ethylene glycol solvent) allows greater control over NTA growth and enables fine-tuning of morphology. Electrochemical reduction of the NTA significantly lowers electrode resistance, thereby enhancing oxygen vacancies and leading to a two-order-of-magnitude rise in charge carrier density (from 2.20 × 10¹⁹ cm⁻³ to 1.03 × 10²¹ cm⁻³), as determined by Mott-Schottky analysis. The electrode exhibits a high areal capacitance of 1517 $\mu$F cm⁻² and a phase angle of $-81.5°$ at 120 Hz. This performance compares favorably with most carbon-based kHz supercapacitor electrodes. The upper-frequency limit of operation for the pseudocapacitor, as measured by the self-resonance frequency, is a high value of 80 kHz.

High-capacity transition metal chalcogenides exhibit intrinsically low conductivity and ion transport efficiency when applied to sodium-ion energy storage devices. Here, carbon-encapsulated WS_x precursors are synthesized using high chloride hydrolysis properties combined with a hydrothermal process. Afterwards, WSSe₂/C anode with dual anion effect is prepared by replacing some S atoms in WS_x with Se atoms employing a microwave sintering process. The obtained WSSe₂/C electrode exhibits a significantly enlarged crystal spacing by constructing built-in electric fields, which ensures rapid and stable Na⁺ transport. The carbon-encapsulated strategy aims to improve electrical conductivity while providing a buffer medium for volume expansion during electrochemical phase transitions. Additionally, by exploring the effects of different carbon introductions on the electrochemical properties, it is determined that 1 g ribose encapsulated WSSe₂ (WSSe₂/C-1) provides the best intervening effect. Consequently, in the assembled Na half-cell, the WSSe₂/C-1 anode displays a high specific capacity of 715.3 mA h g⁻¹ after 200 cycles of activation at 1 A g⁻¹. Further, the assembled sodium-ion capacitor exhibits a high-capacity retention of 86.5 % after 13,000 cycles at a high-power density of 3800 W kg⁻¹. This strategy of combining carbon encapsulation and dual anion effect provides a reference for developing high-power density anodes.

Aqueous Zinc-Ion Batteries (AZIB), as a promising class of multivalent metal-ion batteries, have garnered attention for their exceptional safety and extremely high theoretical capacity. Despite these advantages, their adoption has been impeded by a notable capacity shortfall relative to Lithium-Ion Batteries (LIB). Addressing this challenge, our research leverages glutamic acid as a chelating agent to craft barium-doped ammonium vanadate nanoflowers through a hydrothermal approach, serving as an innovative AZIB cathode material. The incorporation of barium ions has notably expanded the doping distance from 9.817 Å to 12.900 Å, markedly diminishing the diffusion resistance of Zn²⁺ ions and unveiling a plethora of active sites. These structural enhancements have fostered accelerated ion transport and bolstered redox kinetics. Our fabricated cathode material exhibits exceptional reversibility during the redox transitions between V⁵⁺/V⁴⁺ and V³⁺ and the zinc ion doping process. Utilizing BNVO-3 as the cathode, which presents an ideal crystal configuration, the AZIB achieved near-perfect Coulombic efficiency. Impressively, at a current density of 0.1 A g^-1, it achieved a remarkable peak discharge capacity of 384.91 mAh g^-1. Furthermore, after 1500 cycles at 5A g⁻¹, it maintained an impressive 92.9 % capacity retention. This study heralds a new era for barium-doped vanadium-based AZIB cathodes, characterized by their high stability, reversibility, and capacity.

As the candidate for electrolyte in lithium metal batteries, quasi-solid electrolytes have been affected by the growth of lithium dendrites and the continuous reaction between lithium and electrolyte. Herein, we introduce a quasi-solid electrolyte, ZIF-67@ZIF-8/PVDF-HFP (PHMx), with multi-stage ion transport channels. Additionally, we have developed Zeolitic Imidazolate Frameworks (ZIFs) materials that possess a “cage” structure, which is defined as dual-MC nanoparticles. PVDF-HFP in PHMx serves as mechanical backbone, with dual-MC nanoparticles densely and uniformly distributed within the PVDF-HFP. The synergistic effect of the microporous structure of the PVDF-HFP and that of the dual-MC nanoparticles is utilized to construct multi-stage ion transport channels. PHM9 achieves uniform Li⁺ deposition and inhibits the continuous reaction between lithium and electrolyte. Therefore, PHM9, not only achieves high ionic conductivity of 3.2 × 10⁻³ S cm⁻¹ but also remains stable for 1600 h during Lithium-symmetric cycling. Lithium metal battery, assembled with LiFePO₄ as the cathode material, exhibited stable cycling for 400 cycles at a rate of 0.2 C, demonstrating a capacity retention rate of 86.6 %. Similarly, the lithium metal battery utilizing LiCoO₂ as the cathode material demonstrated stable cycling for 200 cycles at a rate of 0.2 C, exhibiting an impressive capacity retention rate of 96.7 %.

Prismatic and pouch packaging formats are commonly used in LiNi_xCo_yMn_zO₂ (NCM) batteries for electric vehicles, each showing distinct failure dynamics. However, a comprehensive study is lacking on how these packaging types affect thermal runaway (TR) at the cell level and its propagation at the module level, with a particular gap in understanding the dynamics of multidimensional signals. In this study, we experimentally explore the effect of cell format on 40 Ah NCM523 prismatic and pouch battery failure behaviors under overcharging and overheating conditions, by applying multidimensional signals, including the swelling force, gas, voltage, and temperature of the batteries. Results indicate that both types of batteries exhibit similar time scales for the failure modes when overcharged. In contrast, under overheating conditions, the pouch batteries fail significantly earlier than the prismatic batteries, including abnormal swelling, venting, gas emission, internal short circuit, and TR. Additionally, the prismatic batteries can withstand a swelling force of 5000 N at venting, while it is 2000 N for the pouch batteries. During TR, the prismatic batteries present a maximum temperature increase rate below 100 K/s, while the pouch batteries exhibit one over 200 K/s. Furthermore, the pouch batteries generally display more severe TR hazards and faster TR propagation than the prismatic cells. This study enhances the comprehension of TR and TR propagation mechanisms across different cell formats, providing crucial insights for the safety design and early warning strategies of battery modules.

The hydrolysis of silicon and its compounds to produce hydrogen for fuel cell remains a major problem. In this work, the active metal calcium and lithium are introduced into the silicon system by preparing Li–Ca–Si ternary alloy. The preferential hydrolysis of active metal in the alloy led to the formation of weakly alkaline environment. It is proved that 25 % Li–CaSi₂ alloy (25 Li) with a large number of secondary nano-phase has the highest electrochemical activity through electrochemical tests, the presence of the secondary nano-phase optimizes the reaction kinetics. Then the 25 Li shows the rapidest kinetics and highest yield in 0.5 M NaF solution, delivering a hydrogen yield of 590 mL g⁻¹ in 20 min and maintain a long-term stable dehydrogenation. In addition, the system still reaches a retention rate of 89 % after exposing to air for 24 h. Furthermore, the above system achieves hydrogen-electric conversion in fuel cell tests. This work provides a novel idea for the research of Si-water system for hydrogen production, and provides a reference for the practical applications on fuel cells in the future.

Reversible solid oxide fuel cell (rSOC) is an efficient means of converting chemical energy into electrical energy, offering a promising solution to the imbalance between energy production and consumption. The performance of rSOC in dual-mode operation, utilizing syngas as fuel, is significantly influenced by variations in fuel composition. This study aims to develop an rSOC model using Aspen Plus and the extreme learning machine (ELM) algorithm to evaluate the impact of different fuel compositions on stack performance in both solid oxide fuel cell (SOFC) and solid oxide electrolytic cell (SOEC) modes. Results indicate that the concentrations of H₂ and H₂O are critical for optimal performance in dual-mode operation. Additionally, the water gas shift (WGS) reaction is employed to modify syngas composition for improved performance. When the molar fraction of H₂/H₂O is maintained between 50 % and 60 %, the rSOC achieves a maximum round-trip efficiency of 67.5 %. The optimal syngas composition, with H₂/H₂O/CO₂/CO ratios of 50/5/35/10, can reach a maximum round-trip efficiency of 68.5 %. This study provides theoretical insights into the selection of syngas composition for rSOC in dual-mode operation.

The permeation of H₂ through the membranes of proton exchange membrane water electrolyzers (PEMWEs) is a critical safety concern because of the risk of explosion when H₂ mixes with O₂ at the anode and increases in concentration. In this study, we investigated the modification of the cathode catalyst layer in the membrane electrode assembly as a strategy for achieving the safe operation of PEMWEs. The effects of the polytetrafluoroethylene (PTFE) content and type of ionomer in the cathode catalyst layer on the dissolved H₂ concentration, H₂ crossover, and electrochemical performance were investigated. The lowest dissolved H₂ concentration and H₂ permeation rate were achieved when 8 wt% PTFE was used. Consequently, the H₂ volume fraction in O₂ at the anode was less than 0.88 %. Additionally, using the Nafion ionomer (D520, ion exchange capacity: 1 mmol g⁻¹), H₂ volume fractions of 1.27 % and 1.34 % were obtained at 0.08 and 5 A cm⁻², respectively. These values are below the lower explosion limit of H₂ in O₂ (4 %), implying that the PEMWE can be safely operated in the low-to-high current density range under ambient pressure. These results provide key guidelines for the design of high-safety cathode catalyst layers for PEMWEs.