Effective Li3AlF6 Surface Coating for High-Voltage Lithium-Ion Battery Operation

Enhancing the energy density of high-voltage lithium-ion battery cathodes is challenging. Cathode surface coating can effectively suppress the irreversible side reactions occurring at the cathode/electrolyte interface. Recent high-throughput theoretical studies have demonstrated the potential of a ternary lithium fluoride, beta-Li3AlF6, as a coating agent owing to its high anodic limit, sufficient stability against various cathode materials, and sufficient Li+-ion conductivity. This study improves the cathode performance by the surface coating of beta-Li3AlF6 on LiNi0.5Mn1.5O4 and LiCoO2 cathodes using a simple sol-gel calcination process. beta-Li3AlF6-coated LiNi0.5Mn1.5O4 shows superior cycle performance, with a capacity retention of 98.2% and a coulombic efficiency of 99% at the 100th cycle. Further, beta-Li3AlF6-coated LiCoO2 can be cycled at a high voltage of 4.5 V with a capacity retention of 95% at the 100th cycle. These results demonstrate the potential of beta-Li3AlF6 as a high-voltage cathode coating agent.

Automated summary

The study demonstrates the potential of beta-Li3AlF6 as a high-voltage cathode coating agent by improving the cathode performance through surface coating on LiNi0.5Mn1.5O4 and LiCoO2 electrodes. The coated cathodes show superior cycle performance with high capacity retention, showcasing the stability and conductivity of beta-Li3AlF6 as a coating material.