Silicic Acid-Assisted Interface Engineering Strategy to Improve the Performance of Li_1.2Mn_0.6Ni_0.2O₂ Cathode Material

Li-rich Mn-based cathode materials Li1.2Mn0.6Ni0.2O2 (LMNO) are potential cathode materials for high energy density lithium-ion batteries. However, the low initial Coulombic efficiency (ICE), voltage/capacity decay, and poor rate performance still remain as the main challenges for commercialization. In this work, an innovative silicic-acid-assisted interface engineering strategy was used to improve the performance of LMNO effectively. Silicic acid interacts with LMNO to form an in situ Li2SiO3 coating accompanied by the formation of surface oxygen vacancy, which greatly suppresses the interface side reaction and irreversible O2 release, improves the electrical conductivity, and thus enhances structural stability and rate performance. As a result, the ICE of LMNO can be increased from 60.3% to 75.5%; the capacity retention rate after 200 cycles at 1C is still as high as 86.8% with a very small voltage fading value of 140 mV.