Investigation the sodium storage kinetics of H1.07Ti1.73O4@rGO composites for high rate and long cycle performance

Insertion type material has been attracted plenty of attentions as the anode of sodium ion batteries (SIBs) due to the low volume change induced long cycle stability. H1.07Ti1.73O4 (HTO), a two-dimensional layered material, is a new insertion type anode material for SIBs reported in this study. Layered HTO composites were decorated with rGO nanosheets via an electrostatic assembly method followed by hydrothermal treatment. When adapted as the anode material of SIBs, HTO@rGO composite exhibits an enhanced sodium ion storage behavior, including high rate capability and long cycle stability. It can deliver high capacities of 142.8 and 66.7 mA h g(-1) at 100 and 10 000 mA g(-1), respectively. Moreover, it can keep a capacity of 75.1 mA h g(-1) at 5 A g(-1) after even 5000 cycles, corresponding to a high capacity retention of 70.8% (0.0058% capacity decay per cycle). HTO exhibits a small volume expansion of 19.6% by in-situ transmission electron microscopy (in-situ TEM). The diffusion coefficient of sodium ions is increased from 1.77 x 10(-14) cm(2) s(-1) in HTO composites to 4.80 x 10(-14) cm(2) s(-1) in HTO@rGO composites. Our designed and synthesized HTO@rGO provides a new route for high rate and long cycle stable SIBs anode materials.

Automated summary

This study introduces a new insertion type anode material H1.07Ti1.73O4 (HTO) for sodium ion batteries (SIBs) that exhibits high rate capability and long cycle stability as a result of being decorated with rGO nanosheets to form HTO@rGO composite. With high capacities and retention rates, HTO@rGO provides a new pathway for the development of high-performance SIBs.