Perpendicular edge oriented graphene foam supporting orthogonal TiO₂(B) nanosheets as freestanding electrode for lithium ion battery

We report three-dimensional (3D) freestanding electrodes based on edge-oriented multilayer graphene (EOG) foam loaded with oriented TiO₂ (B) nanosheets for lithium ion battery that exhibits large capacity and extremely long cycling stability. In contrast to the commonly reported graphene/graphite foams (GFs) that consist of lateral graphene/graphite sheets, EOG foam, with perpendicular graphene network to fully expose the chemically active graphene edges, was developed as a better scaffold to support active materials. Orthogonally oriented TiO₂(B) nanosheets were densely grown on the EOG foam but had straight channels for facile electrolyte access, thus producing a rationally-designed nanostructured architecture. Such a TiO₂(B)/EOG freestanding electrode demonstrated large capacities and high-rate performance. Particularly, it exhibited unprecedented cycling stability with capacity retention of 82% after 12,000 charge-discharge (C-D) cycles. It is expected this new electrode architecture as well as the EOG foam will find broad applications in further development of high performance lithium ion batteries and other electrochemical energy technologies.