Engineering two-dimensional pores in freestanding TiO₂/graphene gel film for high performance lithium ion battery

As the key component of electrochemical energy storage devices, an electrode with superior ions transport pores is the important premise for high electrochemical performance. In this paper, we developed a unique solution process to prepare freestanding TiO₂/graphene hydrogel electrode with tunable density and porous structures. By incorporating room temperature ionic liquids (RTILs), even upon drying, the non-volatile RTILs that remained in the gel film would preserve the efficient ion transport channels and prevent the electrode from closely stacking, to develop dense yet porous structures. As a result, the dense TiO₂/graphene gel film as an electrode for lithium ion battery displayed a good gravimetric electrochemical performance and more importantly a high volumetric performance.