Nickel-rich cathode materials have attracted considerable interest because of their high specific capacities, voltage ranges, and low cost. However, serious capacity attenuation and poor rate performance limit their application. This study proposes a novel strategy to improve the cycle stability of the nickel-rich LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) layer material by designing core–shell LiNi_0.8Co_0.1Mn_0.1O₂ (CS-NCM811). CS-NCM811 is designed by the characteristic reaction between dimethylglyoxime (C₄H₈N₂O₂) and nickel ion to form Ni(C₄H₇N₂O₂)₂. The CS-NCM811 is characterized with high nickel content in its core and high manganese content on its surface, leading to a high capacity and excellent cycle stability. The capacity retention of CS-NCM811 was 72.8%, much higher than that of NCM811 (47.1%) after 500 cycles at a rate of 5 C. Not only is this method a novel strategy to design high capacity cathode materials but also provides some new insights into the cycle stability of nickel-rich layered cathode materials.