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 center dot g(-1) are considered some of the most promising cathode materials, although they suffer from some unsolved problems. In this paper, a series of Li1.2Ni0.2Mn0.6-xAlxO2 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 Li1.2Ni0.2Mn0.56Al0.04O2@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 Li1.2Ni0.2Mn0.56Al0.04O2@Li2CO3 and graphite show an energy density of 443.7 Wh center dot 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.

Automated summary

In this study, Li1.2Ni0.2Mn0.6-xAlxO2 cathodes with an in situ-synthesized Li2CO3 coating layer were used to improve their electrochemical performance. The coating layer inhibited the structural transition and reduced the generation of Mn3+. The Li1.2Ni0.2Mn0.56Al0.04O2@Li2CO3 coating sample showed excellent capacity retention and low voltage decay. Lithium-ion full cells composed of Li1.2Ni0.2Mn0.56Al0.04O2@Li2CO3 and graphite exhibited high energy density with good capacity retention.