Free-standing and binder-free lithium-ion electrodes based on robust layered assembly of graphene and Co3O4 nanosheets.

Free-standing and binder-free Co3O4/graphene films were fabricated through vacuum filtration and thermal treatment processes, in which sheet-like Co3O4 and graphene were assembled into a robust lamellar hierarchical structure via electrostatic interactions. The morphological compatibility coupled with strong interfacial interactions between Co3O4 and graphene significantly promoted the interfacial electron and lithium ion transport. When used as a binder-less and free-standing electrode for lithium-ion batteries, the hybrid film delivered a high specific capacity (~1400 mA h g(-1) at 100 mA g(-1) based on the total electrode weight), enhanced rate capability and excellent cyclic stability (~1200 mA h g(-1) at 200 mA g(-1) after 100 cycles). This effective strategy will provide new insight into the design and synthesis of many other composite electrodes for high-performance lithium-ion batteries.