Li Shifu, Liu Liang, Dai Yiting, Shen Jiacheng, Xu Jiantie
School of Environment and Energy, National Engineering Laboratory for VOCs Pollution Control Technology and Equipment, Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou 510640, China.
School of Physics and Optoelectronics, South China University of Technology, Guangzhou 510641, China.
ACS Appl Mater Interfaces. 2025 Aug 6;17(31):44470-44480. doi: 10.1021/acsami.5c08727. Epub 2025 Jul 27.
As a promising anode for sodium-ion batteries (SIBs), bismuth (Bi) with a high theoretical volumetric capacity of 3750 mAh cm and optimal operation voltage plateau suffers from severe volume expansion and the formation of an unstable solid-electrolyte interphase. Although expanded graphite (EG) mitigates volume changes of Bi in the Bi@EG composite, the sluggish transportation kinetics of Na between graphitic structures remains a bottleneck. Herein, we report a series of Bi@EG ( = 0.2, 0.4, 0.6, and 0.8) and Bi@hEG ( = 0.6 and 0.8) composites as anodes for SIBs. Benefiting from the synergistic effect between the high capacity of Bi nanoparticles and the layered/holey structures of holey expanded graphite (hEG), Bi@hEG exhibited exceptional sodium storage properties including excellent rate capabilities (e.g., 232.0 and 206.3 mAh g at 10 and 20 A g, respectively) and long cycling stability (e.g., a high reversible capacity of 234.9 mAh g after 4000 cycles at 5 A g with an initial capacity retention of 93.5%). When it was paired with NaV(PO) as the cathode (NVP//Bi@hEG), NVP//Bi@hEG achieved a high initial capacity of 102.1 mAh g at 1 C (1 C = 117 mA g) and maintained a high reversible capacity of 86.7 mAh g after 900 cycles at 10 C with an 84.9% initial capacity retention.
