Multi-dimensional construction of a novel active yolk@conductive shell nanofiber web as a self-standing anode for high-performance lithium-ion batteries

Bi-Based Electrode Materials for Alkali Metal-Ion Batteries

Alkali metal (Li, Na, K) ion batteries with high energy density are urgently required for large-scale energy storage applications while the lack of advanced anode materials restricts their development. Recently, Bi-based materials have been recognized as promising electrode candidates for alkali metal-ion batteries due to their high volumetric capacity and suitable operating potential. Herein, the latest progress of Bi-based electrode materials for alkali metal-ion batteries is summarized, mainly focusing on synthesis strategies, structural features, storage mechanisms, and the corresponding electrochemical performance. Particularly, the optimization of electrode-electrolyte interphase is also discussed. In addition, the remaining challenges and further perspectives of Bi-based electrode materials are outlined. This review aims to provide comprehensive knowledge of Bi-based materials and offer a guideline toward more applications in high-performance batteries.

Fabrication of Fe3 O4 Dots Embedded in 3D Honeycomb-Like Carbon Based on Metallo-Organic Molecule with Superior Lithium Storage Performance

A novel metallo-organic molecule, ferrocene, is selected as building block to construct Fe₃ O₄ dots embedded in 3D honeycomb-like carbon (Fe₃ O₄ dots/3DHC) by using SiO₂ nanospheres as template. Unlike previously used inorganic Fe₃ O₄ sources, ferrocene simultaneously contains organic cyclopentadienyl groups and inorganic Fe atoms, which can be converted to carbon and Fe₃ O₄ , respectively. Atomic-scale Fe distribution in started building block leads to the formation of ultrasmall Fe₃ O₄ dots (≈3 nm). In addition, by well controlling the feed amount of ferrocene, Fe₃ O₄ dots/3DHC with well-defined honeycomb-like meso/macropore structure and ultrathin carbon wall can be obtained. Owing to unique structural features, Fe₃ O₄ dots/3DHC presents impressive lithium storage performance. The initial discharge and reversible capacities can reach 2047 and 1280 mAh g^-1 at 0.05 A g^-1 . With increasing the current density to 1 and 3 A g^-1 , remarkable capacities of 963 and 731 mAh g^-1 remain. Moreover, Fe₃ O₄ dots/3DHC also has superior cycling stability, after a long-term charge/discharge for 200 times, a high capacity of 1082 mAh g^-1 can be maintained (80% against the capacity of the 2nd cycle).

Bio-inspired spider-web-like membranes with a hierarchical structure for high performance lithium/sodium ion battery electrodes: the case of 3D freestanding and binder-free bismuth/CNF anodes

High gravimetric energy density and volumetric energy density energy storage devices are highly desirable due to the rapid development of electric vehicles, and portable and wearable electronic equipment. Electrospinning is a promising technology for preparing freestanding electrodes with high gravimetric and volumetric energy density. However, the energy density of the traditional electrospun electrodes is restricted by the low mass loading of active materials (e.g. 20%-30 wt%). Herein, a biomimetic strategy inspired by the phenomenon of the sticky spider web is demonstrated as a high performance anode, which simultaneously improves the gravimetric and volumetric energy density. Freestanding carbon nanofiber (CNF) membranes containing over 50 wt% of bismuth were prepared by electrospinning and subsequent thermal treatment. Membranes consisting of CNF network structures bonded tightly with active Bi cluster materials, resulting in excellent mechanical protection and a fast charge transport path, which are difficult to achieve simultaneously. The composite membrane delivers high reversible capacity (483 mA h g^-1 at 100 mA g^-1 after 200 cycles) and high rate performance (242 mA h g^-1 at 1 A g^-1) as a lithium-ion battery anode. For use as a sodium ion battery, the composite membrane also shows a high reversible specific capacity of 346 mA h g^-1 and outstanding cycling performance (186 mA h g^-1 at 50 mA g^-1 after 100 cycles). This work offers a simple, low cost and eco-friendly method for fabricating free-standing and binder-free composite electrodes with high loading used in LIBs and SIBs.