Hollow-sphere ZnSe wrapped around carbon particles as a cycle-stable and high-rate anode material for reversible Li-ion batteries

Abstract

Hollow-sphere ZnSe is successfully obtained through Ostwald ripening. Carbon nanoparticles are designed and utilized to form a wrapped carbon network as a conductive buffering matrix by subsequent annealing. The ZnSe/C composites, as anode materials for lithium-ion batteries (LIBs), exhibit excellent Li⁺ storage properties, delivering a high reversible capacity of 573.7 mA h g⁻¹ at 1.0 A g⁻¹ after 800 cycles. Even upon increasing the high current density to 20.0 A g⁻¹, the reversible capacity can achieve 318.8 mA h g⁻¹ after 5000 cycles. The superior rate capability is confirmed through the current density return from 20.0 to 1.0 A g⁻¹, and ZnSe/C composites still recover up to 469 mA h g⁻¹, with a retention of 92%. The enhanced electrochemical performances of ZnSe/C composites are attributed to the unique structure and the introduction of conductive carbon networks, which can improve the Li⁺ diffusion coefficient in the insertion and extraction process. Furthermore, the interconnected network also alleviates the volume variation during cycling and further enhances the structural stability.