Constructing Hierarchical Hollow Microspheres with Cos/Co9s8 Heterostructured Nanosheets for High-Performance Sodium Storage

Abstract

Transition metal sulfides have drawn increasing attention as anode materials for sodium-ion batteries (SIBs) due to their high theoretical capacities. However, their practical application is still hindered by the rapid decay of capacity and severe volume variation during cycling. Herein, we constructed a hollow microspheres material composed of CoS/Co9S8 heterostructured nanosheets through a one-step solvothermal method. When applied as the anode for SIBs, CoS/Co9S8 exhibited a superior specific capacity of 600 mAh g−1 after 100 cycles at 0.5 A g−1, and a remarkable cycling performance of 530 mAh g−1 after 800 cycles at 5 A g−1. The outstanding electrochemical performance can owe to the unique three-dimensional hollow hierarchical structure, which can effectively alleviate volume expansion during cycling. Moreover, density functional theory calculation further verified the improved electronic conductivity and structural stability because of the CoS/Co9S8 heterostructure.

Keywords: sodium-ion battery, Heterostructure, Three-dimensional hierarchical structure, Cobalt sulfides, Anode material