Synthesis of functionalized graphite oxide films by three-dimensional self-assembly for lithium ion battery anodes

Functionalized graphite oxide films are synthesized by using (NH4)2SO4 during self-assembly process of graphite oxide in water. Instead of stacking layer by layer, graphite oxide films with three-dimensional (3D) structure are obtained due to strong hydration of ions from (NH4)2SO4. After low temperature treatment (400 °C) of the self-assembly films, (NH4)2SO4 decomposes and N-doped films are obtained, the films can be used directly as anodes for lithium ion batteries. According to electrochemical test, the 3D self-assembly films exhibit enhanced lithium ion storage performances such as initial coulombic efficiency and specific capacity due to 3D structure and N atoms. Further studies show that owing to low chemical activities of graphitic structure in air, low temperature treatment (400 °C) under different atmospheres (N2 or air) has little effect on structures and electrochemical performances of 3D self-assembly films, which is meaningful for producing the films on a large scale in the future.