2D lamellar structured Bi Sb1-@NC toward cycle-stable lithium/sodium-ion storage with high-capacity

The structural instability and capacity limitations of bismuth (Bi) and antimony (Sb) pose significant challenges for their implementation in Li + /Na + energy storage systems. Therefore, designing two-dimensional (2D) Bi and Sb alloy materials with a specialized structure serves as an efficacious method for addressing their defects. In this work, we successfully synthesized a BiSb binary alloy nanoparticles in 2D N-doped carbon nanosheets with controlled ratios via thermal-drying and pyrolysis. Notably, outstanding performance is demonstrated by the Bi 0.5 Sb 0.5 @NC anode, showing both high capacity and exceptional cycling stability during Li + and Na + intercalation processes. In lithium-ion batteries (LIBs), the Bi 0.5 Sb 0.5 @NC anode specifically reaches a capacity of 570 mAh g −1 after 300 cycles at 0.5 A g −1 and exhibits exceptional cycling stability, maintaining 430 mAh g −1 after 1000 cycles at 3 A g −1 . Comparable performance is also shown in sodium-ion batteries (SIBs), which maintains 345.3 mAh g −1 after 500 cycles at 3 A g −1 . The proposed strategy, which integrates binary alloy with nitrogen-enriched carbon matrix, demonstrates promising viability for implementing alloy-type anodes in both LIBs and SIBs. This architectural design effectively addresses challenges associated with alloy-based electrodes while enhancing electrochemical performance. • Structurally stable 2D Bi x Sb 1 -x @NC nanosheets anode with controlled ratios are successfully prepared. • The Bi 0.5 Sb 0.5 @NC anode exhibits exceptional lithium and sodium storage performance. • The alloy strategy and nitrogen doping in carbon co-improving sodium ion storage performance.