Enhanced electrochemical performance of Li1.2Ni0.2Mn0.6-xAlxO2 cathodes in an in situ Li2CO3 coating by a one-step method.

Cathodes must accommodate the excellent performance of the applied anodes in lithium batteries. Li-rich Mn-based cathode materials with a specific capacity beyond 250 mAh·g⁻¹ are considered some of the most promising cathode materials, although they suffer from some unsolved problems. In this paper, a series of Li_1.2Ni_0.2Mn_0.6-xAl_xO₂ cathodes with an in situ-synthesized Li₂CO₃ coating layer by a one-step method is utilized to enhance their electrochemical performance by inhibiting the transition from a layered structure to a spinel structure and reducing the generation of Mn³⁺. The Li_1.2Ni_0.2Mn_0.56Al_0.04O₂@Li₂CO₃ coating sample exhibits an excellent capacity retention rate of 89.5% and a small voltage decay of 1.11 mV per cycle after 200 cycles at 1 C. Lithium-ion full cells composed of Li_1.2Ni_0.2Mn_0.56Al_0.04O₂@Li₂CO₃ and graphite show an energy density of 443.7 Wh·kg⁻¹ at 0.1 C, and the capacity retention rate is 95.6% after 200 cycles at 1 C. These results offer prospects for satisfying the high energy density requirements of electric equipment. [ABSTRACT FROM AUTHOR]