In-situ synthesis of self-standing SbBi-porous carbon fibers enabling ultra-stable sodium-ion storage

Abstract

Alloy-type anodes often suffer from rapid capacity decay due to severe volume expansion during cycling despite their intrinsically high theoretical capacities, which limits their practical application in sodium-ion batteries (SIBs). In this study, we developed an in-situ synthesis strategy to grow nanoscale SbBi alloy structures within a porous carbon fiber matrix (SbBi-PCF), yielding a self-standing SbBi-PCF composite anode with exceptional structural stability. Benefiting from the inherently high Nastorage capability of the SbBi alloy, the SbBi-PCF electrode delivers a high specific capacity of ~259.8 mAh g -1 at 0.1 A g -1 . Remarkably, the self-standing SbBi-PCF anode achieves a record-breaking cycling stability with a capacity retention of ~81.4% after 40,000 cycles-surpassing all previously reported alloy-based anode materials for SIBs.We believe that this alloy-based, ultra-durable anode offers a promising pathway toward the development of high-performance SIBs for large-scale grid energy storage applications.