Bimetallic Synergistic Modified Layer Promotes the Cyclic Stability of Licoo2 under 4.6 V High Voltage

One of the most popular cathode materials for lithium-ion batteries in 3C electronics is layered LiCoO2 (LCO). Higher energy density is made possible by raising the charging cut-off voltage of LCO to 4.6 V. However, if the cut-off voltage (relative to Li/Li+) is more than 4.5 V, a number of issues, including structural instability and significant side reactions with the electrolyte, could occur. To address this problem, here, the Al and Ti bimetallic synergistic modified layer is constructed on the surface of commercial LCO (AT-LCO) by sol-gel method. At high voltage, the Li+ diffusion rate of AT-LCO is enhanced, surface side reactions and harmful phase transitions are attenuated. The capacity retention of AT-LCO at 0.5C and 4.6 V after 500 cycles is 62.2 %, which is superior to that of the unmodified LCO. This work provides useful hints for the development and utilization of long-life high-voltage LCO materials in the future.