Oxygen Vacancy Modulated TiP2O7‐y with Enhanced High‐rate Capabilities and Long‐term Cyclability used as Anode Material for Lithium‐ion Batteries.

Oxygen‐deficient TiP2O7‐y is synthesized by solvothermal and high‐temperature solid‐phase methods. X‐ray powder diffraction (XRD) test data analyses reveal that the solvothermal reaction time can affect the density of oxygen defects in the TiP2O7‐y. Fourier transform infrared spectra (FT‐IR) shows that there is a blue shift in the P−O bond because of the presence of oxygen vacancies. It is strongly demonstrated that oxygen vacancies exist in TiP2O7‐y because electron paramagnetic resonance (EPR) shows sharp peaks at g=2.003. Oxygen vacancy modulated TiP2O7‐y with exposed (541) face shows long cycling stability and super high‐rate capabilities. The initial discharge capacity of TiP2O7‐y, which was prepared after solvothermal reaction for 18 h, reached 828.4 mAh g−1. It can still maintain 246.9 mAh g−1, at 0.5 A g−1, after 500 cycles. Even cycled at 5 A g−1, the reversible rate capacity was maintained at 209.7 mAh g−1. Oxygen vacancies can not only improve the electronic conductivity of TiP2O7‐y but also increase the lithium‐ion diffusion rate. [ABSTRACT FROM AUTHOR]