Deriving Stable SEI Layer and Preventing Aluminum Current Collector Corrosion via Preferential Decomposition of Concentrated Lithium Salt for Lithium‐Ion Batteries

ABSTRACT Among promising lithium salts for electrolyte in lithium‐ion batteries (LIBs), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) forms a more stable inorganic‐rich SEI layer. However, its implementation is limited by severe aluminum current collector corrosion. Since lithium hexafluorophosphate (LiPF 6 ) contributes a stable passivation layer for aluminum, a simply‐mixed LiPF 6 ‐LiTFSI dual‐salt electrolyte offers reduced corrosion. However, its corrosion inhibition capability is not complete. Herein, we propose a SEI‐stabilizing and corrosion‐preventing layer (SCL) that realizes spatial separation of salts, which confines concentrated LiTFSI within a polyethylene glycol dimethacrylate (PEGDMA) network at the anode‐LiPF 6 electrolyte interface. The locally high concentration of LiTFSI in SCL induces a kinetic preference that overrides the thermodynamic preference of LiPF 6 , w…