Nano-dispersed Sb-Bi alloys with tunable microstructures for long-cycle and high-rate potassium-ion storage

Antimony (Sb)-based anode materials suffer from poor cycling stability in potassium-ion batteries (PIBs) due to severe volume changes during charge/discharge processes, which limit their practical application. To address this challenge, a dual strategy of alloying and carbon coating was employed, resulting in the successful synthesis of composite anodes comprising porous carbon-coated SbBi nanoalloys with tunable Sb/Bi atomic ratios. This approach significantly enhances the structural stability and electrochemical performance of Sb-based anodes. The optimized Sb 0.5 Bi 0.5 @C anode exhibits exceptional cycling stability, delivering a high reversible capacity of 316.0 mA h g −1 after 600 cycles at 0.2 C, and remarkable rate capability (230.0 mA h g −1 at 5.0 C). Moreover, it demonstrates improved thermal stability at 45°C, retaining a capacity of 328.6 mA h g −1 after 1000 cycles at 2.0 C. The potassium storage mechanism is elucidated through kinetic analysis and theoretical calculations. Furthermore, full-cell configurations were assembled and evaluated, demonstrating promising practical application potential with similarly outstanding electrochemical performance.