Bio-derived yellow porous TiO: the lithiation induced activation of an oxygen-vacancy dominated TiO lattice evoking a large boost in lithium storage performance.

Oxygen deficient TiO has attracted extensive attention owning to its narrow bandgap and high electrical conductivity. In this work, novel yellow TiO with hierarchically porous architecture is fabricated by a facile pyrolysis method in air via a biomass template. The obtained yellow TiO exhibits interesting lithiation induced activation during cycling, which gives rise to a phase change from poorly crystallized TiO to an amorphous phase, accompanied by a colour change from yellow to black. In contrast to the intercalation mechanism reported in most of the literature on the TiO anode of LIBs, notably, the reversible redox reaction between Ti and metal Ti can be verified in this case, demonstrating the novel conversion reaction mechanism of the TiO electrode. Based on this, the yellow porous TiO delivers enhanced electrochemical performance as an anode for LIBs with a superior capacity of 480 mA h g at 5 A g and a high capacity of 206 mA h g at 10 A g after 8000 cycles.