A versatile opened hollow carbon sphere with highly loaded antimony alloy for ultra-stable potassium-ion storage

Carbon materials meet the stringent practical requirements for anodes for potassium-ion batteries (PIBs) due to their abundance and chemical stability. The major issue of carbon-based anodes is the low specific capacity and poor cyclic stability. Equally importantly, scalable synthesis approaches for electrodes are highly desired for the future application in large-scale energy storage systems. Herein, we developed a novel composite of Sb encapsulated in N/P co-doped opened hollow carbon spheres (N/POHCs) with high Sb loading through a simple carbonization and subsequent impregnation process. Beneficial from the virtue of abundant pyridinic-N-P bonding and opened hollow spherical structure advantages, N/POHCs exhibit much lower diffusion barrier than that of pure carbon, prominent Sb carrier capability, as well as the extraordinary resistance to volume expansion. The resulting Sb@N/POHCs composite delivers a high specific capacity of 533.3 mAh g- 1 at 0.1 A g- 1 with an initial Coulombic efficiency of 83 %, and can maintain a specific capacity of 345 mAh g- 1 at 1 A g- 1 after 4000 cycles. This work provides rational structure design with universal carrier capability of active materials to achieve high-capacity and long cycle life anode for advanced PIBs accompanied by the potential for large-scale production.