Template-free synthesis of mesoporous succulents-like TiO2/graphene aerogel composites for lithium-ion batteries

Highlights: • Mesoporous succulents-like TiO₂/GA composites were synthesized through a template-free method. • The sample TiO₂/GA-3 exhibits a high specific capacity and well cycling stability. • Mesostructure and 3D structure of samples facilitate their electrochemical performances. -- Abstract: Mesoporous succulents-like titanium dioxide (TiO₂)/graphene aerogel (GA) composites are synthesized through a facile template-free method. The growth mechanism of the composites has been studied, which can be attributed to the Ostwald ripening mechanism. The succulents-like TiO₂ submicron flowers grow in situ on the surface of GA. Moreover, they show a unique mesoporous structure. Due to the synergistic interaction of unique mesoporous succulents-like structure of TiO₂ and 3D continuous structure of GA, the composites exhibit an excellent electrochemical performance. The mesostructure of composites can not only improve the Li⁺ diffusion kinetics without great loss of tap density, but also facilitate the penetration of the electrolyte. When used as anode materials for lithium ion batteries, the TiO₂/GA composites exhibit high superior capacity, good rate capability and long cycling stability. A reversible capacity of 663.2 mA h g⁻¹ can be obtained at a current density of 100 mA g⁻¹ after 250 cycles, and even at a high current rate of 5 A g⁻¹, a reversible capacity of 215.5 mA h g⁻¹ can also be achieved after 4000 cycles. Owning to the simple synthesis method, unique microstructure, and excellent electrochemical performance, our work might apply a practical high-performance anode material for lithium ion batteries.