Self-Template Construction of Hierarchical Bi@C Microspheres as Competitive Wide Temperature-Operating Anodes for Superior Sodium-Ion Batteries
Yan Wang, Y.D. Kuang, Jie Cui, Xijun Xu, Fangkun Li, Yiwen Wu, Zhaoyu Sun, Weizhen Fan, Yanxue Wu, Jingwei Zhao, Zhiyuan Zeng, Jun Liu, Yanping Huo
Abstract
Huge volume changes of bismuth (Bi) anode leading to rapid capacity hindered its practical application in sodium-ion batteries (SIBs). Herein, porous Bi@C (P-Bi@C) microspheres consisting of self-assembled Bi nanosheets and carbon shells were constructed via a hydrothermal method combined with a carbothermic reduction. The optimized P-Bi@C-700 (annealed at 700 °C) demonstrates 359.8 mAh g –1 after 1500 cycles at 1 A g –1 . In situ/ex situ characterization and density functional theory calculations verified that this P-Bi@C-700 relieves the volume expansion, facilitates Na + /electron transport, and possesses an alloying-type storage mechanism. Notably, P-Bi@C-700 also achieved 360.8 and 370.3 mAh g –1 at 0.05 A g –1 under 0 and 60 °C conditions, respectively. Na 3 V 2 (PO 4 ) 3 //P-Bi@C-700 exhibits a capacity of 359.7 mAh g –1 after 260 cycles at 1 A g –1 . These hierarchical microspheres effectively moderate the volume fluctuation, preserving structural reversibility, thereby achieving superior Na + storage performance. This self-template strategy provides insight into designing high-volumetric capacity alloy-based anodes for SIBs.