Batteries & Supercaps最新文献

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.

Supercapacitors (SCs) are a promising electrochemical device in the field of electrochemical energy storage, but their wide range applications are limited by relatively low energy density. Asymmetric supercapacitors (ASCs) based on different positive and negative electrodes offer the possibility to increase the energy density by extending the voltage window. It is essential to explore novel electrode materials to boost the electrochemical properties of ASCs. Metal-organic frameworks (MOFs) have emerged as ideal electrode materials for SCs, due to their high porosity, tunable structure and highly dispersed active sites. MOFs can also be used as templates or precursors for the preparation of versatile electrode materials, such as carbon materials and metal compounds. In this minireview, SCs and MOF-based electrode materials are first introduced, followed by an overview of recent advances in the synthesis of MOF-based electrode materials including pristine MOFs, MOF derivatives and their composites, and their applications in ASCs acted as negative electrode, positive electrode or both. Finally, the challenges and prospects of MOF-based ASCs are discussed.

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.

The generation of e-waste from lithium ion batteries (LIBs) is rapidly increasing due to the rising utilization of LIBs in portable electronics, and electric vehicles, with an average life span of 3–5 years. The disposal of spent LIBs is a major environmental concern due to the presence of high percentages of toxic heavy metals and corrosive electrolytes. Efficient and sustainable recycling of spent LIBs has become immensely important, both environmentally and from a circular economy perspective, as LIBs serve as secondary sources of critical metals needed for renewable energy conversion and storage systems. We provide a concise review of metal recovery from spent LIBs using waste biomass in a green and sustainable approach for resource generation, in addition to the valorization of waste biomass. Biomass is used to recover metals from spent LIBs, acting as lixivient, reductant, and as absorbent. We have also discussed a reverse strategy utilizing ‘black mass’ from spent LIBs as catalyst for biomass conversion to value-added products. The concept of “circular economy” is highlighted in a “killing two birds with one stone” approach through the utilization of biomass for the recovery of metals from spent LIBs and vice versa.

Owing to the high theoretical capacity of 3860 mAh g⁻¹ and low redox potential, lithium metal is the best candidate for the development of next generation high-energy density lithium-ion batteries. However, notorious lithium dendrites growth and the poor compatibility of liquid electrolyte hinder the commercialization of lithium metal batteries. In this work, an anode-less system was used to understand the change in lithium deposition on Cu current collector after the additional functionalized-polysiloxane (PE) layer. The PE structure consists of lithiophobic and lithiophilic side chains which facilitate the uniform lithium deposition on Cu substrate. This evidence was collected by scanning electron microscopy (SEM) after the cycling test of half-cell configuration and the lithium deposition with different current densities. The reversibility was improved by 5 % compared with the bare Cu. In addition, the potential polarization was lowered after the addition of PE layer on bare Cu. Thus, the higher cycle stability (40 %) and more stable coulombic efficiency are observed on the PE@Cu||NCM83 cell compared with the bare-Cu||NCM83 during the cycle test.

Battery development has traditionally focused on high energy and long lifetime cells, but there is now a shift towards their sustainability and safety. One example of this trend is the search for fluorine-free conductive salts. The overwhelming majority of lithium-ion conductive salts contain fluorine, which is critical regarding their environmental impact, sustainability, and toxicology. In this study, we perform a comprehensive investigation of the performance and aging mechanisms of cell components with LiClO₄ as conductive salt in high-voltage NMC622‖Graphite pouch cells. The cells containing LiClO₄ show poorer electrochemical performance compared to their LiPF₆ equivalents. However, to the best of our knowledge, a mechanistic understanding of the effect of LiClO₄ on the aging of electrode and electrolyte components for high-voltage cells is largely missing. Developing such an understanding will pave the way toward designing alternative salts to LiPF₆, ultimately leading to fluorine-free and more sustainable battery cells. Our results show, that the chlorination of ethyl methyl carbonate at both methyl and ethyl groups and the formation of large (Li_w)Al_xO_yCl_z composite deposits on the cathode surface result from perchlorate degradation at the cathode. This leads to increased cell resistance, reduced capacity retention, and accelerated degradation of the LiClO₄-containing electrolytes.

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).