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

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