Evolution effect of Ti-based modifiers awards improved lithium ion diffusion rate of single crystal nickel-rich cathode

Abstract Modified single-crystal materials would be triumphantly synthesized by solvothermal method to enhance the electrochemical reversibility and alleviate the harmful phase transition of nickel-rich materials during battery operation. XRD presented that the Li layer spacing and Li+/Ni2+ miscibility of Ti doped materials increased 2.16% and decreased 36.28% respectively compared with pure materials. TEM and XPS results manifested that TiO2 and Li2Ti3O7 coating could significantly inhibit the deposition of residual lithium and the release of lattice oxygen, which further improved the structural stability of the material. The electrochemical test indicated that the electrochemical properties of Ti-based modified material had been significantly increased. Especially, 0.01 mol Ti-modified material had excellent cycle retention (92.02% at 3 C and 25 °C, 80.81% at 3 C and 60 °C) and low lithium-ion diffusion attenuation (54.74% at 3 C) after 150 cycles. XRD and TEM results after cycling shown that the internal and external crystal structure of the material could be effectively protected by the evolved Li2Ti3O7 and Li4Ti5O12 mixed coatings. This effective design strategy was expected to be extended to the commercial application of other cathode materials.