Electrophoretic Deposition of Binder-Free MnO2/Graphene Films for Lithium-Ion Batteries

Binder-free, nano-sized needlelike MnO2-submillimeter-sized reduced graphene oxide (nMnO(2)-srGO) hybrid films with abundant porous structures were fabricated through electrophoretic deposition and subsequent thermal annealing at 500 degrees C for 2 h. The as-prepared hybrid films exhibit a unique hierarchical morphology, in which nMnO(2) with a diameter of 2050 nm and a length of 300500 nm is randomly anchored on both sides of srGO. When evaluated as binder-free anodes for lithium-ion half-cell, the nMnO(2)-srGO composites with a content of 76.9 wt% MnO2 deliver a high capacity of approximately 1652.2 mA.h.g(-1) at a current density of 0.1 A.g(-1) after 200 cycles. The high capacity remains at 616.8 mA.h.g(-1) (ca. 65.1% capacity retention) at a current density as high as 4 A.g(-1). The excellent electrochemical performance indicates that the nMnO(2)-srGO hybrid films could be a promising anode material for lithium ion batteries (LIBs).