Cr3+-doped TiNb2O7 nanorods for ultra-fast charging lithium-ion batteries: Enhanced through structural and electronic engineering

TiNb2O7 is regarded as an ideal anode candidate for next-generation lithium-ion batteries because of the high theoretical specific capacity and operating potential. However, poor multiplicity performance and low intrinsic conductivity hinder their application. We have designed one-dimensional Cr3+-doped titanium niobate nanorods (TNO-Cr) by combining the advantages of heteroatom doping and nanosizing in order to improve the electronic conductivity. The optimal Cr3+-doped TNO anode material (TNO-6.0%Cr) maintains a discharge capacity of 125.1 mAh g-1 after 2000 cycles at 5C and 104.5 mAh g-1 even after 1000 cycles at 10C. In addition, NCM811//TNO-6.0%Cr maintains a discharge capacity of 119 mAh g-1 at 100 cycles at full cell 1C. The great electrochemical performance is attributed to its one-dimensional nanostructure that shortens the lithium-ion diffusion distance and the successful substitution of Cr for Ti sites that narrows the bandgap width and improves the ionic conductivity. The materials can be used as promising anode materials for fast-charging lithium-ion batteries.