High nickel ternary materials are the preferred cathode material for electric vehicle power batteries due to the advantage of high energy density. Nevertheless, the electrochemical performance deteriorates due to the unstable structure of the high nickel cathode material. To address this issue, a solid phase sintering process introduces alkali metal Na⁺ with a larger ion radius into LiNi_0.8Co_0.1Mn_0.1O₂ (Na@LNCM). In the crystal structure of Na@LNCM material, Na⁺ ions occupied the Li⁺ sites, resulting in the decrease of lithium-nickel mixing in Na@LNCM and maintain the structural stability of the material. Meanwhile, Na⁺ doping increases the interlayer spacing of Na@LNCM and plays a key role in supporting the structure of the material, which is beneficial to accelerating the transportation of Li⁺ during charge–discharge cycles. The cycling and rate performances of Na@LNCM are apparently improved by Na⁺ doping in this study. So, Na⁺ doped high nickel cathodes can be used in high performance lithium-ion batteries.