Scalable fabrication of Bi@N-doped carbon as anodes for sodium/potassium-ion batteries with enhanced electrochemical performances

Metallic bismuth as a promising anode for alkali metal-ion batteries has attracted great attentions because of superb volumetric capacity (3800 mA h cm−3) and suitable working voltage plateaus (∼0.5 V). However, Bi anode suffers from large volume change during repeated cycling, resulting in poor cycle performance. In this contribution, Bi nanoparticles embedded in N-doped carbon materials (Bi@N-C) are designed and fabricated by one-step pyrolysis method. Thanks to the synergistic effects of Bi nanoparticles and the N-doped carbon framework, the elaborately designed Bi@N-C can not only reduces the ion/electron diffusion pathways and enhances the reaction kinetics, but can also availably inhibits the agglomeration of Bi particles, and effectively alleviates the volume fluctuation. As an anode material, the Bi@N-C exhibits advanced rate capability (219 mA h g−1 at 5 A g−1) and excellent stable cycle ability (307 mA h g−1 at 1 A g−1, after 400 cycles) in sodium-ion batteries. Furthermore, the Bi@N-C anode also exhibit good stable cycle ability (240 mA h g−1 at 1 A g−1, after 70 cycles) in potassium-ion batteries. This study provides a facile and environmentally friendly way for fabricating high performance Bi anodes towards SIBs and PIBs.