Improved performance of Li-Se battery based on a novel dual functional CNTs@graphene/CNTs cathode construction

A dual functional CNTs@graphene/CNTs cathode for Li-Se battery was constructed by a CNTs@ graphene network and a CNTs interlayer. CNTs were first integrated with graphene to form a three-dimensional (3D) framework and work together as a conductive matrix for Se confinement. The optimized composite cathode delivers a high initial capacity of 575 mAh.g(-1) at 0.5 A.g(-1) and good rate capacity with a retained capacity of 479 mAh.g(-1) at 2.0 A.g(-1) (73% of the capacity at 0.2 A.g(-1)). CNTs were further served as an interlayer to confine the diffusion of polyselenides by constructing a thin CNTs layer outside the CNTs@graphene network. An improved initial capacity of 616 mAh.g(-1) at 0.5 A.g(-1) is achieved with a retained capacity of 538 mAh.g(-1) after 80 cycles, indicating the effective dual function of CNTs in this novel cathode construction and great application potential for Li-Se battery.