Preparation of Lithium Titanate/Reduced Graphene Oxide Composites with 3D “Fishnet-Like” Conductive Structure via a Gas-Foaming Method for High-Rate Lithium-Ion Batteries

Using ammonium chloride (NH4Cl) as the pore-forming agent, three-dimensional (3D) “fishnet-like” lithium titanate/reduced graphene oxide (LTO/G) composites with hierarchical porous structure are prepared via a gas-foaming method. SEM and TEM images show that in the composite prepared with the NH4Cl concentration of 1 mg mL−1 (1-LTO/G), LTO particles with sizes of 50~100 nm disperse homogeneously on the 3D “fishnet-like” graphene sheets. The nitrogen-sorption analyses reveal the existence of micro/mesopores, which is attributed to the introduction of NH4Cl into the gap between the graphene sheets that further decomposes into gases and produces hierarchical pores during the thermal treatment process. The loose and porous structure of 1-LTO/G composites enables the better penetration of electrolytes, providing more rapid diffusion channels for lithium ion. As a result, the 1-LTO/G electrode delivers an ultrahigh specific capacity of 176.6 mAh g−1 at a rate of 1 C. Even at 3 C and 10 C, the specific capacity ...