Encapsulation of Bi 2 S 3 Within Multifunctional Sulfurized Polyacrylonitrile Matrix Enables High‐Performance Wide‐Temperature Sodium/Potassium‐Ion
Fuyu Xiao, Xinye Li, Yiyi Wang, Fenqiang Luo, Lihui Chen, Zhenyang Huang, Xin Chen, Renpin Liu, Xiaochuan Chen, Lingxing Zeng, Qingrong Qian, Qinghua ChenABSTRACT
With high theoretical capacity and low cost, bismuth sulfide (Bi 2 S 3 ) demonstrates considerable potential as an anode for sodium/potassium‐ion batteries (SIBs/PIBs). Unfortunately, significant volume variation, low electrical conductivity, and dissolution of polysulfides drastically weaken their intrinsic merits. Herein, we fabricate a Bi 2 S 3 ‐SPAN composite by confining Bi 2 S 3 nanoparticles within a sulfurized polyacrylonitrile (SPAN) nanofiber matrix. In this architecture, the confinement effect of SPAN inhibits the aggregation of Bi 2 S 3 nanoparticles and alleviates the volume expansion during charge and discharge. Critically, the “solid–solid” conversion mechanism significantly suppresses the “dissolution–shuttle” effect of polysulfides. These merits ensure that Bi 2 S 3 ‐SPAN anode presents prominent sodium/potassium storage performance across a broad temperature range (−15°C to –50°C), demonstrating its environmental adaptability. Especially, in SIBs, Bi 2 S 3 ‐SPAN anode harvests capacities of 259 mAh g −1 (90.9% retention) over 770 cycles and 537 mAh g −1 (85.2% retention) over 230 cycles at 0.5 A g −1 under −15°C and 50°C, respectively. The full cells also achieve excellent electrochemical performances. Notably, Bi 2 S 3 ‐SPAN‐450||NVP pouch cell delivers a stable capacity of 183 mAh after 300 cycles at 0.2 A g −1 . This work is expected to offer inspiration for relieving volume expansion and the “dissolution–shuttle” effect of polysulfides in metal sulfide electrode materials for advanced SIBs/PIBs.