▎ 摘　　要

Transition metal sulfides(TMSs) are an ideal alternative for use in lithium-ion batteries(LIBs) owing to their high theoretical capacity and environmental advantages. However, bulk expansion problems of TMSs and the classical method of electrode synthesis limit their large-scale development. In this study, 3D hydrangeashaped Co9S8 @graphene nanocomposites were successfully prepared by one-step in-situ pyrolytic sulfidation. The resulting Co9S8 @graphene composites were tested as anodes of LIBs and showed excellent electrochemical properties with a high discharge specific capacity of 1530.3mAh center dot g(-1) at a current density of 0.1 A center dot g(-1), superior multiplicative properties reaching 415.7mAh center dot g(-1) at a current density of 5 A center dot g(-1), and rapid recovery to 726.4mAh center dot g(-1) when the current density returned to its initial value. The electrodes also displayed superior capacity retention and cycling stability at high current densities with a stable discharge capacity of 550mAh center dot g(-1) after 1000 cycles at a current density of 1 A center dot g(-1). These features were attributed to the 3D hydrangea-like graphene structure, which greatly increased the specific surface area of the material, facilitating contact with the electrolyte during electrochemical reactions. The nanoparticles also provided more space, thereby improving the volume expansion of the material during the electrochemical processes. In sum, these findings offer a new synthetic route to future preparation of metal sulphide@graphene composites. (c) 2022 Elsevier B.V. All rights reserved.