Insights into the enhanced Lithium-Ion storage performance of CoSx/Carbon polyhedron hybrid anode

Abstract

In this work, the 3D cobalt sulfide/carbon polyhedral (CoSx/CP) hybrids (x = 1, 2) have been fancily prepared by employing the ZIF-67 as template. The as-prepared CoSx/CP inherit the structure of ZIF-67, realizing the polyhedral structure where the CoSx nanoparticles are well embedded. The battery performance measurements demonstrate that the CoS2 has played a significant role contributing to the lithium ions batteries (LIBs) performance of CoSx/CP. As a result, the capacity of the optimized CoSx/CP is 562 mAh g−1 after 300 cycles at 0.5 A g−1. When cycled at 10 A g−1, it delivers a reversible specific capacity of 131 mAh g−1. The electrochemical analysis points out that the optimized CoSx/CP possesses diverse electrochemical reactions and the lowest charge transfer resistance. Moreover, the insertion mechanism and structural evolution process of CoSx/CP are examined by the in-situ XRD. Beyond that, the unique nanoarchitecture of CoSx/CP guarantees the high specific surface area which enables the large electrode–electrolyte contract area, fast ions diffusion/electron transfer and robust structural stability. Meanwhile, the carbon skeleton is deductive to confine the huge volume expansion of CoSx as well.