Layer-by-layer self-assembly of graphene-like Co₃O₄ nanosheet/graphene hybrids: Towards high-performance anode materials for lithium-ion batteries

We have successfully synthesized graphene-like Co(OH)₂ and fabricated sandwich-like Co(OH)₂/graphene hybrids by the electrostatic self-assembly. After annealing at low temperatures, we further fabricated Co₃O₄ nanosheet/graphene hybrids, in which the thickness of graphene-like Co₃O₄ nanosheets is only ∼5 nm. The as-prepared product exhibits a very high reversible lithium storage capacity up to 982.6 mAh g⁻¹ after 50 cycles, while pure Co₃O₄ nanosheets only show the discharge capacity of 108 mAh g⁻¹ after 50 cycles. Moreover, in comparison with the reported results, it exhibits an ultrahigh rate capability of 209.7 mAh g⁻¹ at 5000 mA g⁻¹. The greatly improved electrochemical performances may be ascribed to the sandwich-like structure of ultrathin Co₃O₄ nanosheet/graphene. - Highlights: • Graphene-like Co₃O₄ nanosheet/graphene hybrids have been successfully synthesized. • The Co₃O₄/graphene hybrids exhibit a very high reversible lithium storage capacity. • The Co₃O₄/graphene hybrids also exhibit an ultrahigh rate capability.