Graphene Oxide-Wrapped Porous Hollow CoO Microspheres with Enhanced Lithium Storage Performance.

Porous hollow CoO microspheres wrapped with graphene oxide were synthesized by a step solvothermal method and subsequent heat treatment. Benefiting from the design of special porous hollow microspheres, the effective specific surface area was greatly increased, the sufficient contact between the porous hollow CoO microspheres and electrolyte was achieved, and then a charge specific capacity of 888.59 mA h g was gained. Meanwhile, partial stress from the charging/discharging process was greatly relieved due to the abundant pores and hollow structure, excellent cycling stability was realized, and the charge specific capacity of the 1000th cycle was 465.75 mA h g at 5 C (1 C = 890 mA g). In addition, the conductivity of CoO microspheres was effectively improved due to the tight package of graphene oxide to CoO microspheres, and superior rate performance was attained (280.99 mA h g at 10 C).