SO42−-ion induced synthesis of 3D porous hydrangea-shaped anatase TiO2 as high performance anode material for lithium/sodium-ion batteries

TiO2 materials are considered one of the promising candidates for lithium/sodium-ion batteries (L/SIBs) due to its excellent safety and abundant resources. However, the low ion diffusion coefficient becomes a bottleneck in restrict its development. In this work, three-dimensional (3D) porous hydrangea-shaped anatase TiO2 (ATO) was synthesized through the synergistic effect of de-alloying and SO42− induced chemical synthesis. During the chemical synthesis process, SO42− and TiO62− octahedra are bound by static electricity, as the spatial effect of SO42− can influence the octahedral arrangement in favor of precipitating anatase TiO2. In the SIBs, ATO as anode material provided an excellent capacity of 190 mAh g−1 after 100 cycles at a current density of 50 mA g−1. Electrochemical kinetic tests show that the pseudocapacitive behavior contributes to 86% of the capacity at a scan rate of 1 mV s−1, mainly due to the high specific surface area provided by its unique microstructure, and also shows excellent electrochemical performance in the LIBs tests. This study provides a novel strategy for the simple and large-scale production of TiO2 anode materials with high-performance L/SIBs.