Study on preparation and electrochemical properties of nano-sized LiNi0.05Mn1.95O4 cathode materials
To effectively suppress Jahn-Teller effect of spinel lithium manganate and improve the problem of rapid capacity decay during high-rate charge discharge cycles,the LiNi0.05Mn1.95O4 samples were successfully prepared by using a molten salt combustion method and different calcination temperatures.The experiment results demonstrated that the crystal struc-ture of LiMn2O4 did not change under Ni-doping and different calcination temperatures.With the rise of calcination tempera-ture,the crystallinity and particle size of the samples were increased continuously.Besides,the particle sizes were gradually increased from nanoscales to submicron scales.The optimal calcination temperature of 650℃ delivered excellent electro-chemical performance.The initial discharge specific capacity at 5C and the capacity retention rate after 500 cycles were 100.8 mA·h/g and 80.0％,respectively.At a higher rate of 10C,the capacity of 500 cycles only attenuated by 7.5％.The dy-namic performance test results indicated that it had a large lithium-ion diffusion coefficient of 3.26×10-16 cm2/s and a smaller apparent activation energy of 25.67 kJ/mol.Ni doping and different calcination temperatures inhibited the Jahn-Teller effect of LiMn2O4 materials,thereby promoted the rate performance and cycle life of LiMn2O4 materials.
spinel LiMn2O4Ni-dopingmolten-salt combustion methodJahn-Teller effectcalcination temperature
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