Ni-rich layered transition metal oxide is a promising cathode candidate for lithium-ion batteries owing to its superior advantages, e.g., high energy density, low cost, and eco-friendly. Nevertheless, the capacity fading usually occurs for a high Ni content cathode. Herein, we introduce a surface modification of LiNi_0.8Mn_0.1Co_0.1O₂ (NMC811) cathode by the mechanofusion process that can enhance electrochemical capacity and cycling stability, especially for 18650 cells. The modified NMC811 shows outstanding performance with high-capacity retention compared to the uncoated NMC because coating materials can prevent direct contact between the electrolyte and NMC811 cathode and enhance ionic and electronic conductivities.