Synergistic effect of amorphous carbon coverage and enlarged voltage window on the superior lithium storage performance of nanostructured mesoporous anatase TiO2: Emphasis on interfacial storage phenomena

Mesoporous anatase TiO2 nanoparticles coated with an ultrathin layer of amorphous carbon are hydrothermally synthesized. Used as an anode material, it achieves a sustained superior lithium storage performance, presenting a high reversible capacity of 270 mA h g−1 up to 300 cycles at a current density of 30 mA h g−1 in an enlarged voltage window of 0.01-3 V, which is firstly adopted for TiO2 anode material. Remarkably, the carbon coated TiO2 nanoparticles can still maintain a capacity of 171 mA h g−1 at 300 mA g−1 after 1000 cycles, and even 93 mA h g−1 at 600 mA g−1 after 1000 cycles. We propose an overall view on the diverse features influencing the electrochemical performance of the high-surface-area mesoporous carbon coated TiO2 nanoparticles and emphasize that the excellent performance is the synergistic result of the enlarged voltage window, which leads to higher interfacial lithium storage, and the uniform amorphous carbon coverage, which not only improves electrical conductivity, minimizes the direct solid-electrolyte interphase (SEI) formation, but also helps to avoid the structure instability arising from the enlargement of the potential window.