Abstract:LiNi_0.8Co_0.1Mn_0.1O₂ powder was prepared by mixing LiOH·H₂O and co-precipitated Ni_0.8Co_0.1Mn_0.1(OH)₂ at a molar ratio of 1:1.05, followed by sintering at different temperatures. The effects of temperature on the morphology, structure and electrochemical performance were extensively studied. SEM and XRD results demonstrate that the sintering temperature has large influence on the morphology and structure and suitable temperature is very important to obtain spherical materials and suppresses the ionic distribution. The charge-discharge tests show that the electrochemical performance of LiNi_0.8Co_0.1Mn_0.1O₂ powders becomes better with the increase of temperature from 700 °C to 750 °C and higher temperature will deteriorate the performance. Although both of materials obtained at 750 °C and 780 °C demonstrate almost identical cyclic stability at 2C rate, which delivers 71.9% retention after 200 cycles, the rate performance of powder calcined at 780 °C is much poorer than that at 750 °C. The XRD results demonstrate that the poor performance is ascribed to more severe ionic distribution caused by higher temperature.

Key words: lithium ion battery; LiNi_0.8Co_0.1Mn_0.1O₂; sintering temperature; cycling performance; rate performance