In order to improve the electrochemical performance of the high-voltage spinel cathode material,LiNi0.5Mn1.5O4(LNMO)was prepared by a high temperature solid state method using Ni0.25Mn0.75(OH)2 as raw material.The effects of TiO2 coating and treatment temperatures on the physical and chemical properties,morphology,crystal structure,and electrochemical performance of the as-obtained samples were studied.The results show that the surface modification effect is optimal when the coating dosage is 0.5％and the heat treatment temperature is 750 ℃.The electrochemical properties of the coated samples are significantly improved compared with those of the pristine ones.The 0.1 C capacity of the coin cell at 3.5-4.95 V is 130.8 mA·h·g-1,and the capacity retention reaches 90.9％after 100 cycles.At an appropriate heat treatment temperature,both of TiO2 coating and surface doping coexist on the surface of LNMO@Ti particles.A small amount of TiO2 on the surface can preferentially react with residual HF in the electrolyte,playing a role in protecting the cathode active material.Ti ions entering the surface layer lattice can optimize the superficial structure and enhance the stability of the"cathode/electrolyte"interface during the charging and discharging cycles.
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