Effects of porous hedgehog-like morphology and graphene oxide on the cycling stability and rate performance of CoO/NiO microspheres.

A porous hedgehog-like CoO/NiO/graphene oxide (denoted as PHCNO/GO) microsphere was prepared by a facile solvothermal method, followed by an annealing treatment under argon atmosphere. Benefiting from the thin CoO/NiO nanosheets with a large specific surface area, abundant pores distributed between the CoO/NiO nanosheets, and GO firmly wrapped around the surface of PHCNO microspheres, the PHCNO/GO microspheres showed excellent lithium storage performance. The CoO/NiO nanosheets provided numerous active sites, achieving a high reversible specific capacity. The pores distributed between the CoO/NiO nanosheets created numerous diffusion pathways for lithium ions and relieved stress from the charging/discharging process. Meanwhile, GO supported the PHCNO microspheres, enhancing their cycling stability. A high reversible specific capacity of 383.9 mA h g was maintained after 1000 cycles at 3000 mA g. In addition, GO improved the conductivity of PHCNO microspheres and then achieved a good rate performance; a high reversible specific capacity of 526.7 mA h g was obtained at 5000 mA g. This work provided a reference for synthesizing high-performance lithium-ion battery anode materials.