Tailored dealloying-driven, graphene-boosted defective rutile TiO for long-term lithium storage

Ti 3+ self-doping and/or an oxygen defect-induced impurity level in TiO 2 lattices can serve as charge transfer carriers to accelerate electronic conduction, enabling TiO 2 to be a promising anode alternative in lithium-ion batteries. Although previously reported post-reduction of Ti( iv ) intermediates and direct oxidation of Ti( ii ) precursors can be used to prepare defective rutile TiO 2 , these processes usually require elevated temperatures. Herein, a tailored low-temperature dealloying approach, involving a new in situ oxidation-reduction mechanism, is proposed to synthesize blue defective rutile TiO 2− x directly. The generated air-sensitive Ti 3+ species on the surface are then handily stabilized by coupling with graphene. As a result, the TiO 2− x /graphene composites exhibit desirable lithium storage capacities and outstanding long-term cycling stability (157 mA h g −1 at 1C after 1400 cycles) owing to the [001]-axis oriented nanorod self-assembly, faster electron transfer, and improved Li + diffusivity. This work highlights a new formation mechanism of defective rutile TiO 2− x , and considering the convenience and simplicity, it will provide new inspiration to the conventional dealloying strategy for low-temperature synthetic chemistry. A tailored low-temperature dealloying approach, involving a new in situ oxidation-reduction mechanism, is proposed to synthesize blue defective rutile TiO 2− x directly.