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

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 663.2mA h g(-1) can be obtained at a current density of 100mA 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. (C) 2019 Elsevier Ltd. All rights reserved.