Abstract: A facie solid-state route has been employed to synthesize LiNi_0.8Co_0.1Mn_0.1O₂ material with superior electrochemical performance by varying the oxygen flow rate during the calcination process, and the effect of different oxygen flow rates on the structure and electrochemical performance of LiNi_0.8Co_0.1Mn_0.1O₂ has also been investigated. It reveals that the LiNi_0.8Co_0.1Mn_0.1O₂ material synthesized under a flow rate of 0.1 L/min has the lowest degree of cation mixing among all samples and large d-space. The 0.1 L/min sample shows a discharge capacity of 174 mA·h·g⁻¹ after 100 cycles at 1 C, corresponding to the capacity retention rate of 98.3%. A retention rate as high as 96.8% is achieved at 2 C, and good performance is also obtained in high cut-off votage test. Moreover, we confirm that low oxygen-flow rate can lead to high degree of cation mixing because of high content of Ni²⁺, and high oxygen-flow rate can decrease the d-spacing of LiNi_0.8Co_0.1Mn_0.1O₂ material, thereby being harmful for the Li⁺ intercalation/deintercalation.