Encapsulation of Bi2S3 Within Multifunctional Sulfurized Polyacrylonitrile Matrix Enables High-Performance Wide-Temperature Sodium/Potassium-Ion Batteries Through Solid–Solid Conversion

en This link goes to a English section zh This link goes to a Chinese section 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. 摘要 en This link goes to a English section zh This link goes to a Chinese section 硫化铋(Bi 2 S 3 )因其高理论容量和低成本,作为钠/钾离子电池负极材料展现出巨大潜力。然而,其显著的体积变化、较低的电子电导率以及多硫化物溶解等问题严重削弱了其本征优势。本文通过将Bi 2 S 3 纳米颗粒封装于硫化聚丙烯腈(SPAN)纳米纤维基底中,成功制备了Bi 2 S 3 -SPAN复合材料。在该结构中,SPAN的限域效应有效抑制了Bi 2 S 3 纳米颗粒的团聚,并缓解了充放电过程中的体积膨胀。更关键的是,“固-固”转化机制显著抑制了多硫化物的“溶解-穿梭”效应。这些优势使得Bi 2 S 3 -SPAN负极在宽温域范围(−15°C至50°C)内呈现出优异的钠/钾存储性能,证实其良好的环境适应能力。特别地, 在钠离子电池中,Bi 2 S 3 -SPAN负极在-15°C和50°C条件下,于0.5 A g −1 电流密度下分别实现了770次循环后容量保持259 mAh g −1 (容量保持率90.9%)和230次循环后容量保持537 mAh g −1 (容量保持率85.2%)的优异性能。相应的全电池同样表现出卓越的电化学性能。值得注意的是,Bi 2 S 3 -SPAN-450||NVP软包电池在0.2 A g −1 电流密度下循环300次后,仍能提供183 mAh的稳定容量。这项工作有望为缓解先进钠/钾离子电池中金属硫化物电极材料的体积膨胀和多硫化物“溶解-穿梭”效应提供启示。