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Herein, we describe the synthesis and evaluation of hierarchical mesoporous orthorhombic niobium oxide (T-Nb2O5) as an anode material for rechargeable lithium-ion batteries (LIB). The as-synthesized material addresses key challenges such as beneficial porous structure, poor rate capability, and cycling performance of the anode for Li-ion devices. The physicochemical characterization results reveal hierarchical porous nanostructure morphology with agglomerated particles and a 20 to 25 nm dimension range. Moreover, the sample has a high specific surface area (~65 m2 g−1) and pore volume (0.135 cm3 g−1). As for the application in Li-ion devices, the T-Nb2O5 delivered an initial discharging capacity as high as 225 mAh g−1 at 0.1 A g−1 and higher rate capability as well as remarkable cycling features (~70% capacity retention after 300 cycles at 250 mA g−1) with 98% average Coulombic efficiency (CE). Furthermore, the scan rate-dependent charge storage mechanism of the T-Nb2O5 electrode material was described, and the findings demonstrate that the electrode shows an evident and highly effective pseudocapacitive Li intercalation behaviour, which is crucial for understanding the electrode process kinetics. The origin of the improved performance of T-Nb2O5 results from the high surface area and mesoporous structure of the nanoparticles. [ABSTRACT FROM AUTHOR]

Chloride–ion batteries (CIBs) offer a compelling alternative to conventional battery systems, particularly in applications demanding cost‐effectiveness and resource sustainability. However, the development of tailored electrode materials remains a critical bottleneck for CIB advancement. In this study, an untapped class of perovskite‐based material, potassium hexachlorostannate (K2SnCl6, denoted as KSC) is synthesized via a facile mechanochemical route for the first time. The prepared KSC is subjected to various characterization techniques to confirm its crystal structure and morphology. Herein, KSC exhibits intriguing electrochemical performance in a non‐aqueous CIB configuration, utilizing a lithium metal counter electrode. Furthermore, ex situ X‐ray diffraction (XRD) and X‐ray photoelectron spectroscopy (XPS) analysis, reveal a conversion reaction mechanism involving chloride ion shuttling and provide insights into structural evolution during cycling. Moreover, the density functional theory (DFT) studies support additional degradation products that can potentially limit the performance of these materials as potential battery electrodes in CIBs. [ABSTRACT FROM AUTHOR]

In P2-type layered oxide cathodes, Na site-regulation strategies are proposed to modulate the Na + distribution and structural stability. However, their impact on the oxygen redox reactions remains poorly understood. Herein, the incorporation of K + in the Na layer of Na 0.67 Ni 0.11 Cu 0.22 Mn 0.67 O 2 is successfully applied. The effects of partial substitution of Na + with K + on electrochemical properties, structural stability, and oxygen redox reactions have been extensively studied. Improved Na + diffusion kinetics of the cathode is observed from galvanostatic intermittent titration technique (GITT) and rate performance. The valence states and local structural environment of the transition metals (TMs) are elucidated via operando synchrotron X-ray absorption spectroscopy (XAS). It is revealed that the TMO 2 slabs tend to be strengthened by K-doping, which efficiently facilitates reversible local structural change. Operando X-ray diffraction (XRD) further confirms more reversible phase changes during the charge/discharge for the cathode after K-doping. Density functional theory (DFT) calculations suggest that oxygen redox reaction in Na 0.62 K 0.03 Ni 0.11 Cu 0.22 Mn 0.67 O 2 cathode has been remarkably suppressed as the nonbonding O 2p states shift down in the energy. This is further corroborated experimentally by resonant inelastic X-ray scattering (RIXS) spectroscopy, ultimately proving the role of K + incorporated in the Na layer., (© 2024 The Author(s). Small published by Wiley‐VCH GmbH.)

Calcium (Ca) batteries represent an attractive option for electrochemical energy storage due to physicochemical and economic reasons. The standard reduction potential of Ca (-2.87 V) is close to Li and promises a wide voltage window for Ca full batteries, while the high abundance of Ca in the earth's crust implicates low material costs. However, the development of Ca batteries is currently hindered by technical issues such as the lack of compatible electrolytes for reversible Ca 2+ plating/stripping and high-capacity cathodes with fast kinetics. Herein, we employed FeS 2 as a conversion cathode material and combined it with a Li + /Ca 2+ hybrid electrolyte for Ca batteries. We demonstrate that Li + ions ensured reversible Ca 2+ plating/stripping on the Ca metal anode with a small overpotential. At the same time, they enable the conversion of FeS 2 , offering high discharge capacity. As a result, the Ca/FeS 2 cell demonstrated an excellent long-term cycling performance with a high discharge capacity of 303 mAh g -1 over 200 cycles. Even though the practical application of such an approach is questionable due to the high quantity of electrolytes, we believe that our scientific findings still provide new directions for studying Ca batteries with long-term cycling.