Improving the electrochemical performance of LiNi0.8Co0.1Mn0.1O2 cathodes using a simple Ce4+-doping and CeO2-coating technique

Abstract

LiNi_xCo_yMn_1−x−yO₂ (x ≥ 0.6, NCM) has attracted much attention due to its high specific capacity and energy density. However, capacity attenuation caused by Li⁺/Ni²⁺ mixing and structural instability inhibit its development and application. In order to solve these problems, we report a simple method to synthesize NCM cathodes via a one-step Ce⁴⁺-doping and CeO₂-coating technique, which can reduce the degree of Li⁺/Ni²⁺ mixing and improve the structural stability. The Ce⁴⁺-doping not only effectively reduces the degree of Li⁺/Ni²⁺ mixing, but also enhances the (001) interplanar distance of NCM and improves Li⁺ diffusion. Furthermore, the CeO₂-coating can reduce the direct contact between the NCM particles and electrolyte, which can reduce the harmful interface reaction, thus making the impedance increase more slowly. The Ce⁴⁺-doping and CeO₂-coating of NCM particles led to a capacity retention of 96.3% at 1C (1C = 280 mA g⁻¹) after 100 cycles. Therefore, the synthesis of NCM cathodes via a one-step Ce⁴⁺-doping and CeO₂-coating technique is a superb way to improve the electrochemical properties of the NCM cathode in lithium-ion batteries.