Metal–Organic Framework–Based CoS2 Nitrogen‐Doped Carbon for High‐Performance Lithium Storage

Abstract

Due to their large theoretical capacity, transition metal sulfides are regarded as ideal anode materials for lithium‐ion batteries (LIBs). However, a number of technical challenges and scientific issues, such as low utilization of active materials and large volumetric expansion, must be addressed before it can be used in practice. Herein, CoS2‐embedded N‐doped carbon polyhedrons are constructed successfully and employed as an efficient anode of LIB. After 200 cycles at a current density of 0.2 Ag−1, the optimal CoS2@NC‐400 demonstrates a high reversible capacity of 866.2 mAhg−1, and after 500 cycles at a current density of 0.5 Ag−1, there is no discernible capacity fading. The excellent electrochemical performance of CoS2@NC‐400 can be attributed to that graphitic N‐doped porous carbon provides a highly conductive framework, which facilitates electron transports and lessens the volume expansion of electrode during charging and discharging. Furthermore, the pyrrolic N‐doped carbon in the CoS2@NC‐400 composite allows for a lower diffusion barrier for Li‐ions in the electrode.