Bio-derived yellow TiO2: Lithiation induced activation of oxygen-vacancy dominated TiO2 lattice evoking a large boost in lithium storage performance

Abstract

Oxygen deficient TiO2 absorbs intensive attentions owning to its narrow bandgap and high electrical conductivity. In this work, a novel yellow TiO2 with the hierarchically porous architecture is fabricated by a facile pyrolysis in air via one biomass template. The obtained yellow TiO2 exhibits an interesting lithiation induced activation during cycles, which gives rise to the phase change from poor-crystallized TiO2 to amorphous phase as accompanying with a colour change from yellow to black. Differing to the intercalation mechanism reported in most literature on TiO2 anode of LIBs, notably, the reversible redox reaction between Ti3+ and metal Ti can be verified in this case, demonstrating a novel conversion reaction mechanism of TiO2 electrode. Based on it, the yellow porous TiO2 deliverers an enhanced electrochemical performance as anode of LIBs with the superior capacity of 480 mAh g-1 at 5 A g-1 and the high capacity of 206 mAh g-1 at 10 A g-1 after 8000 cycles.