Batteries & Supercaps最新文献

The Front Cover shows a fully automated sequential robotic experimental setup for the cell fabrication of stacked-type lithium–oxygen rechargeable batteries with a fabrication throughput of over 80 cells per day, which is ten times higher than conventional human-based experiments. The high alignment accuracy during the electrode stacking and electrolyte injection process results in improved battery performance and reproducibility. More information can be found in the Research Article by S. Matsuda and co-workers (DOI: 10.1002/batt.202400509).

The Cover Feature illustrates the advanced fabrication process and structure of flexible micro-supercapacitors (MSCs) with 3D interconnected graphene/carbon nanotube (CNT) composite electrodes. Combining flash lamp annealing (FLA) and laser ablation, this process transforms graphene oxide and CNT films into high-performance, interdigitated MSCs. The resulting devices deliver exceptional energy density, flexibility, and scalability, thus underscoring their potential for flexible electronics and miniaturized energy-storage applications. More information can be found in the Research Article by Y. Myung and T. Y. Kim (DOI: 10.1002/batt.202400557).

2D materials are emerging materials for energy storage and among these layered double hydroxides (LDHs) seem particularly promising due to their structure, easily adjustable composition, and cheapness. This study marks the first reported application of an LDH, specifically NiFe-NO₃ LDH, as conversion anode material in a sodium half-cell, to the best of our knowledge. Despite an initial loss in capacity, the material demonstrates notable stability, retains a high specific capacity even after 50 discharge/charge cycles (~500 mAh/g). The intricate reaction mechanism was explored using various ex-situ techniques such as DC magnetometry and FTIR, as well as in-operando X-ray Absorption Spectroscopy (XAS). The proposed Na-storage mechanism in NiFe-NO₃ LDH involves an initial irreversible “activation” during the first sodiation, characterized by a phase change reaction that leads to the formation of NiO_x and Fe₃O₄, followed by a reversible mechanism involving both intercalation and conversion in subsequent cycles.

We report on the physiochemical behaviour of membranes based on three different polystyrene-b-poly(ethylene oxide)-b-polystyrene (PS-b-PEO-b-PS) block copolymers and an ionic liquid (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIMTFSI)) and their use as solid-state electrolytes in supercapacitors. The nanostructured block copolymers form free standing membranes at high ionic liquid uptake with conductivities above 1 mS/cm at 25 °C, keeping ordered morphologies. We used small angle X-ray scattering (SAXS) to propose the correlation between domain spacing, the copolymer chain length (N) and the interaction parameter (χ_eff) in the block copolymers. We explored the potential of the electrolytes in two high voltage (3.0 V) device configurations, first using carbon nanotube (CNT) electrodes, with excellent electrical conductivity and high-rate capability exhibiting a power density of 5.7 KW/kg at 4 A/g, while devices based on high surface area activated carbon exhibited high energy density of 20.7 Wh/kg at 4 A/g. Overall, both devices deliver superior specific energy and power densities than that of commercial state-of-the-art supercapacitors, based on liquid electrolyte. Additionally, the CNT|Solid-state|CNT device displays higher power density compared to the AC|Solid-state|AC device, highlighting its better suitability for high power applications, while the AC|Solid-state|AC device, is better suited for energy density applications.

Improving electrode performance is crucial for increasing energy efficiency and power density in redox flow batteries. Here, we study the effects of thermal activation of carbon paper electrodes on the performance of bismuth as an electrocatalyst in high-voltage KCrPDTA/K₄Fe(CN)₆ flow batteries. While thermal activation improves wettability and surface area, it also leads to the formation of large, agglomerated bismuth deposits that reduce Coulombic efficiency. Although bismuth lowers cell resistance and enhances voltage efficiency, it promotes parasitic hydrogen evolution depending on its morphology, underscoring the need for optimized catalyst deposition techniques.

In this study, the effect of temperature changes on the voltage decay and current behavior of lithium-ion cells is investigated, focusing on a comparison between open-circuit voltage (OCV) measurements and float current $$ measurements. Using our self-developed advanced Floater system, the voltage decay rates $$ from OCV and float current measurements for three different cell types are assessed. Temperature ramps and steps, ranging from 5 °C to 50 °C, are applied to capture the impact of entropic effects and aging mechanisms. Both methods effectively capture aging dynamics, showing strong agreement between ramp and step measurements. Deviations arise only in cases of strong entropy effects due to differences in measurement strategies. The findings confirm that float currents do not introduce additional aging beyond that captured by OCV measurements. The relationship between OCV and float current is governed by differential capacity $$, which varies with cell voltage and temperature. Furthermore, strong deviations from classical differential voltage analysis but high agreement with local pulse measurements are observed, especially at low depths of discharge. This can be explained by the hysteresis effect of graphite. These findings highlight the benefits of high-precision float current measurements in aging studies, particularly in contrast to simpler OCV methods.

A simple 1D transfer matrix model of a battery is introduced and parametrized using harvested individual cell components at 0 % and 100 % SoC. This model allows for the calculation of group velocity and attenuation. The results of the model show good agreement with measured values, highlighting increased attenuation and group velocity at the resonances. This emphasizes the importance of selecting a suitable interrogation frequency for ultrasound investigations in lithium-ion batteries. The model accurately replicates the observed weakening of resonances with increasing SoC. Additionally, it provides the basis to fit US spectroscopy data in the future, enabling immediate determination of component thickness and the Young's modulus of individual components, along with aiding in the identification aging effects of the anode and cathode materials. The model can visualize wave propagation within the battery. At certain frequencies, standing waves form which could be used in high-intensity ultrasound applications targeted at individual cell components.

Lithium-sulfur (Li−S) batteries have attracted considerable attention due to their advantages, such as high specific capacity, high energy density, environmental friendliness, and low cost. However, the severe capacity fading caused by shuttle effect of polysulfide needs to be addressed before the practical application of Li−S batteries. Crystalline porous materials including MOFs have generated great interest in energy storage fields especially batteries, because the ordered porous frameworks can offer a fast-ionic transportation. Nevertheless, the intrinsic low conductivity of MOFs limits their rapid development in lithium-sulfur batteries. This review mainly discusses the latest research progress on MOF main materials in Li−S batteries. The working principle of Li−S batteries and the classical “adsorption-catalysis-conversion” strategy are briefly introduced. Specifically, three modification methods (non-metal atom doping, single-atom, and dual-atom doping modifications) applied in MOF-based materials are analyzed and summarized, along with their respective mechanisms and advantages and disadvantages. Ligand doping is an effective strategy that can regulate the structure and properties of MOFs, thereby enhancing their catalytic activity and adsorption capacity towards polysulfides. Through ligand doping, key parameters such as the pore size, surface charge, and active site density of MOFs can be controlled, thereby influencing the adsorption and conversion of polysulfides on MOFs surfaces. Furthermore, crucial insights for the rational design of advanced MOF-based materials for lithium-sulfur batteries and the exploration of the main challenges and future directions for their application were also discussed.

The Front Cover illustrates the advantages in the supercapacitive behaviour of cobalt-layered hydroxides achieved through 3D structuring and halide substitution. The 3D flower-like morphology of α-Co hydroxyhalides significantly enhances their electrochemical performance compared to the hexagonal structure. By substituting chloride with iodide, the capacitive behaviour is further improved by over 40 %, thereby showcasing the critical role of halides in modulating electronic properties. This achievement makes these materials promising candidates for energy storage. More information can be found in the Research Article by V. Oestreicher, G. Abellán and co-workers (DOI: 10.1002/batt.202400335).

The Cover Feature illustrates the stable performance of a PVA-based quasi-solid polymer electrolyte. The fast lithium ion movement through the inter- and intra-crystalline pores of the zeolitic pathway enables stable lithium ion flux at the solid electrolyte interface, thus allowing the system to operate even at a high current density of 100 mA cm⁻² without dendrite formation. More information can be found in the Research Article by H. Annal Therese and co-workers (DOI: 10.1002/batt.202400299).