Si─O Molecular Engineering Enhances Cathode-Anode Interface Stability for High-Loading and High-Voltage Layered Cathode-Lithium Metal Batteries.

Nickel-rich layered cathodes and lithium metal anode are promising for the next generation high-energy-density batteries. However, the unstable electrode-electrolyte interface induces structural degradation and battery failure under high-voltage and high-loading conditions. Herein, we report a fluorosilane-coupled electrolyte stabilizer with 1H, 1H, 2H, 2H-perfluorooctyltrimethoxysilane (PFOTMS), which presents higher adsorption energy with LiNiCoMnO cathode than solvents through the conjugation of Si─O bonds and therefore is oxidized on its surface to derive an interfacial layer rich in F and Si─O species. This architecture effectively stabilizes the cathode structure, suppresses transition metal migration, and promotes Li conduction and uniform deposition, which also suppresses the side reactions of electrolyte with both cathode and anode. This unique interfacial stabilization mechanism enables the Li||NCM811 battery to achieve a capacity retention rate of 80.8% after 600 cycles at 4.7 V. The Li||LiCoO cell with a high mass loading of 20 mg cm achieves a remarkably high-capacity retention of 92.79% after 500 cycles at 4.4 V. This work proposes an interfacial stabilization that overcomes high-voltage limitations in practical nickel-rich cathode/lithium metal batteries.