Hierarchical microspheres constructed by Te@N‐doped carbon for efficient potassium storage

Tellurium (Te) has attracted intensive attention for its potential as stationary energy storage system due to its high volumetric capacity and the intrinsic electronic conductivity. Nevertheless, this battery suffers from the low utilization of active Te and the vast volume variations during cycling. Hierarchical N-doped carbon (N-C) porous microspheres etched from MnCO3 microsphere template are designed as a host for Te. The hierarchical microspheres, with abundant pores and voids, shortens the ions diffusion/electrons transport distances and buffers the volume expansion of the active materials. When constructed the K-Te battery, the Te@N-C electrode delivers a remarkable reversible capacity of 390 mA h g(-1) (corresponding to 2437.5 mA h cm(-3)) at 0.1 A g(-1) after 100 cycles and 170 mA h g(-1) (corresponding to 1062.5 mA h cm(-3)) after 2000 cycles at 0.5 A g(-1). This novel design in this work may open up new opportunities for the development of the new energy storage systems with high volumetric energy density.