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.

Automated summary

The study presents a unique structure design of bismuth nanorods confined in hollow N, S-codoped carbon nanotubes to improve the performance of sodium-ion batteries and potassium-ion batteries. The designed structure effectively suppresses particle pulverization and solid-electrolyte interphase (SEI) growth, resulting in outstanding rate capability and high energy density.