Batteries & Supercaps最新文献

The Front Cover depicts the structural degradation of commercial 18650-type lithium-ion battery cathodes that occurs at elevated temperatures. It illustrates the transition path from a well-ordered layered structure (shown in blue) to a spinel intermediate (represented in green), and finally to a rock salt phase (indicated in red). The colour gradient highlights how phase evolution occurs under thermal stress, emphasising the critical role temperature plays in driving structural instability and performance loss in modern Li-ion batteries. More information can be found in the Research Article by A. Senyshyn and co-workers (DOI: 10.1002/batt.202500421).

One of the not so well understood aspects of vanadium redox flow battery cells is the capacity fade that happens during continuous charge–discharge cycles. While several modeling and experimental studies have been reported, reliable data are not available in the open literature. In the present work, long-duration charge–discharge cycling studies are reported in cells of industrial size having an electrode area of about 400 and 1800 cm². The continuous current and cell voltage measurements have been supplemented by periodic measurement of concentration of the electro-active vanadium ions in the positive and the negative electrolytes. The weight of the electrolyte tanks and the open circuit voltage of the cell have also been monitored. The mutual self-consistency of these data has been verified by post-test analyses. Data from over thirteen different cases spanning a range of current densities and electrolyte circulation rates show that the capacity fade is about (0.15 ± 0.05)% per cycle. In all cases, an asymptotic capacity fade pattern is established in which the concentration of V(V) increased and V(IV) decreased steadily on the positive side, and that of V(III) decreased steadily but slightly on the negative side.

A rational structural design is an effective way to enhance the sodium storage cycle stability and reaction kinetics of metal phosphides. Therefore, nitrogen-doped carbon-coated CoP nanosheets are obtained by a facile solvothermal method coupled with a polydopamine coating and phosphorization strategy. Combining the advantages of the nitrogen-doped carbon layer and the nanosheet structure, the pseudocapacitance contribution and reaction kinetics of CoP@NC are significantly enhanced compared to pure phase CoP, as evidenced by electrochemical tests including cyclic voltammetry and GITT. Based on this, CoP@NC exhibits excellent cycling stability and rate performance. A specific capacity of 169 mAh g⁻¹ can be maintained after 100 cycles at a current density of 0.5 A g⁻¹, corresponding to a capacity drop of only 0.2% per cycle. In addition, the CoP@NC electrode can deliver the discharge capacities of up to 303,3 and 106.6 mAh g⁻¹ at 0.1 and 2 A g⁻¹, respectively. These excellent properties demonstrate that CoP@NC is a promising anode material for sodium storage.

The increasing demand for battery cells in the automotive sector forces battery cell manufacturers to accelerate product development and scale-up of their production processes. To achieve this, digitalization expands data acquisition and enables the use of machine learning methods. These methods can be utilized for quality assurance, process optimization, and more. However, the application of machine learning requires a large amount of data, which is especially difficult to acquire in the pre-series production due to the vast number of parameter variations, the complex process chain and the small production quantities. Additionally, these obstacles lead to high costs in pre-series production of battery cells. Therefore, there is a need for methods, which are able to train machine learning models on small datasets and increase their generalization abilities. A possible method for this is transfer learning which can use parts of previous models on a new, but similar problem. This method has scarcely been applied in the context of battery cell manufacturing and motivates a structured literature review about its applicability, challenges, and benefits. This study compares transfer learning methods applied to other industries with machine learning approaches of battery cell manufacturing to identify and evaluate potential use cases.

Porous carbon materials attract substantial research interest as promising electrode materials for supercapacitors, owing to their high specific surface area, excellent electrical conductivity, and remarkable chemical and thermal stability. Diverse synthesis strategies have been explored to improve the electrochemical performance of porous carbon electrodes. Among these, the template method demonstrates significant potential for precisely constructing porous architectures, showing great promise for both probing energy storage mechanisms and fabricating high-performance carbon materials. This review comprehensively examines sacrificial templating strategies for synthesizing porous carbon materials, beginning with an overview of the design principles for hierarchical porous architectures. The templating methods are classified into three main categories—hard, soft, and self-templating—with a discussion of their respective formation mechanisms and recent methodological advances. The influence of these strategies on the morphological, structural, and electrochemical properties of the resulting carbons is analyzed. Finally, current challenges and future research directions are outlined to facilitate the application of templated porous carbons in high-performance supercapacitors.

Metallurgical-grade silicon is a low-cost, high-capacity alternative material for Li-ion battery anodes. Herein, a unique, low specific surface area (SSA) porous silicon with highly regular, parallel, internal pore structure is presented. The relatively low SSA results in a first cycle Coulombic efficiency of over 90% in a half-cell configuration. Balancing (full) cells with high-nickel content cathode material at a limited Si specific capacity around 1000 mAh gSi⁻¹ limits stack expansion to under 4% in a multilayer pouch cell configuration (consisting of double-sided coated anodes and cathode foils). This limited expansion is ascribed to the persistence of a crystalline Si backbone, directing most of the expansion inwards. This mechanism is confirmed by cross-sectional scanning electron microscopy on a lithiated anode and Raman microscopy on a cycled electrode. After 100 cycles, just under 50% of the original amount of c-Si is still present, as detected by X-ray diffraction. For the optimum electrode formulation and particle size distribution (PSD), full cells using NMC622 cathodes last more than 200 cycles before falling below 80% state-of-health, and the porous Si powder significantly outperforms a nonporous powder with a similar PSD.

LiS batteries (LSBs) with their exceptionally high energy density are considered as a more sustainable, green, and cost-effective next-generation energy storage solutions beyond conventional Li-ion batteries (LIBs). Despite their potential, LSBs encounter some key challenges that constrain their commercialization. To tackle these issues and improve the performances of LSBs, researchers have explored various nanomaterials, among which nanowires (NWs) have emerged as one of the potential candidates. Their high aspect ratio ensures efficient electron-ion transport along their length while confining the movement across the radial direction, thereby regulating the reaction kinetics. Additionally, NWs provide exceptional mechanical strength and interface stability, contributing to enhanced cyclic stability. This review begins with summarizing the basic electrochemistry of LSBs and the associated major technical challenges. Next, it presents a comprehensive and systematic overview of the contemporary research progress in the application of NW electrocatalysts across various LSB components including cathode, separator, and interlayer, correlating their key roles in boosting electrochemical performances. The employment of in situ characterization techniques in these systems has also been discussed to get deeper insights. Finally, the review concludes with an outlook on the anticipated prospects of NWs in the future advancement of high-performance LSBs.

This study presents an innovative strategy for utilizing passive cigarette smoke aerosol, a common pollutant, to prepare a sustainable supercapacitor cathode. The cathode system is developed with in situ growth of carbon dots from cigarette smoke aerosol on the acid modified nanoclay (ANc), which reduces the internal resistance of layered silicates. The modified nanoclay is subsequently combined with pseudocapacitive layered MoS₂ to enhance the electrochemical performance by redox reaction during charging and discharging cycles. To achieve optimum conductivity and specific capacitance (Sp.Cp.), both carbon dots and MoS₂ loading are varied and corresponding Sp.Cp. is calculated in the three electrode and asymmetric device configuration, respectively. The successful formation of the carbon dot modified ANc based MoS₂ composite is confirmed through a combination of structural, morphological, and spectroscopic characterization techniques. Asymmetric supercapacitor devices are fabricated using the synthesized nanocomposite as the positive and graphite as the negative electrode in 1 M TEABF₄ /DMSO electrolyte. Among acid modified nanocomposites, the device containing double the quantity of MoS₂ shows a maximum Sp.Cp. of 119.7 F g⁻¹ with 26.7 Wh kg⁻¹ energy density and 500 W kg⁻¹ power density at 1 A g⁻¹ current density. Furthermore, the optimized electrode is able to illuminate red and disco LED lights, highlighting its potential application in sustainable energy storage systems. This work presents a novel approach for utilizing cigarette smoke aerosol into high performance supercapacitor electrode materials.

Water-based liquid electrolytes for Li-ion batteries offer the promise of improved safety and lower cost, but the energy density remains too low due to the narrow electrochemical stability window of water. Switching to the water-in-salt electrolyte approach appears to be an ideal solution as the electrochemical stability window of water is extended, thereby increasing the overall energy density. To date, despite an increase in electrochemical stability window, hydrogen evolution reaction (HER) and oxygen evolution reaction still occur during cycling, resulting in poor electrochemical performance. Most articles report that this phenomenon is intrinsically related to the change in potential within the cell. In the present work, we carry out a complete surface-to-bulk investigation of two well-known electroactive materials used in the water-in-salt system, LiFePO₄ and TiS₂. The aim in this first part is to understand the role of soaking the composite electrode in the water-in-salt electrolyte and to see if degradation occurs prior to any electrochemical measurement. We show that LiFePO₄ is a robust material that develops a surface layer rich in LiF, whereas TiS₂ decomposes at the top surface into a mixture of TiO₂/TiS₂ or oxysulfide byproduct.

The Cover Feature illustrates a battery with sodium vanadium oxide as an electrode material, which is converted to zinc vanadium oxide and zinc hydroxy sulfate upon cycling. It is powering many grid-related applications. The associated Research Article by S. Yan, K. Takeuchi and co-workers (DOI: 10.1002/batt.202500036) describes the prominent electrochemical reactions that are being visualized here and how they relate to electrode morphology and electrolyte composition.