Bismuth Nanorods Confined in Hollow Carbon Structures for High Performance Sodium- and Potassium-Ion Batteries

Bismuth has drawn widespread attention as a prospective alloying-type anode for sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs) due to its large volumetric capacity. However, such material encounters drastic particle pulverization and overgrowth of solid-electrolyte interphase (SEI) upon repeated (de)alloying, thus causing poor rate and cycling degradation. Herein, we report a unique structure design with bismuth nanorods confined in hollow N, S-codoped carbon nanotubes (Bi@NS-C) fabricated by a solvothermal method and in-situ thermal reduction. Ex-situ SEM observations confirm that such a design can significantly suppress the size fining of Bi nanorods, thus inhibiting the particle pulverization and repeated SEI growth upon charging/discharging. The as achieved Bi@NS-C demonstrates outstanding rate capability for SIBs (96.5% capacity retention at 30 A g(-1) vs. 1 A g(-1)), and a record high rate performance for PIBs (399.5 mAh g(-1) @ 20 A g(-1)). Notably, the as constructed full cell (Na3V2(PO4)(3)@C|Bi@NS-C) demonstrates impressive performance with a high energy density of 219.8 W h kg(-1) and a high-power density of 6443.3 W kg(-1)(based on the total mass of active materials on both electrodes), outperforming the state-of-the-art literature. (c) 2021 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.