Ultrathin CoO/Graphene Hybrid Nanosheets: A Highly\nStable Anode Material for Lithium-Ion Batteries

Abstract

Transition metal oxides are promising high-capacity anode\nmaterials\nfor next-generation lithium-ion batteries. However, their cycle life\nremains insufficient for commercial applications. Developing transition-metal\noxide anode materials with a long lifespan through a facile route\nhas become an important issue. This work reports the fabrication of\nultrathin CoO/graphene hybrid nanosheets consisting of ultrafine CoO\nnanoparticles (∼5 nm) densely anchored on the graphene nanosheets.\nThey exhibit a high reversible capacity of ∼1018.0 mAh g^–1 over 520 discharge/charge cycles, and the Coulombic\nefficiency remains ∼100% upon cycling, indicating excellent\ncyclability. The as-obtained CoO/graphene nanocomposite avoids the\nwidespread problem of cracking or pulverization of transition-metal\noxide anode materials upon cycling and retains its original morphology\nand structure even after 520 discharge/charge cycles, benefiting from\nthe synergetic effects of ultrafine CoO nanoparticles and the conductive\ngraphene nanosheets.