Study of the Corrosion Behavior of Cathode Current Collector in LiFSI Electrolyte

Graphical Corrosion of aluminum current collector is critical to the aging of lithium-ion batteries, particularly with lithium bis(fluorosulfonyl)imide based electrolyte. Our results show that corrosion currents in aluminum increase with cycling time and potential, correlating with changes in surface chemistry and morphology. Our findings provide valuable insights for advancing the development of lithium-ion batteries with long lifespan. Cycling aging is the one of the main reasons affecting the lifetime of lithium-ion batteries and the contribution of aluminum current collector corrosion to the ageing is not fully recognized. In general, aluminum is corrosion resistant to electrolyte since a non-permeable surface film of alumina is naturally formed. However, corrosion of aluminum current collector can still occur under certain conditions such as lithium bis(fluorosulfonyl)imide (LiFSI)-based electrolyte or high voltage. Herein, we investigates the corrosion of aluminum current collector in the electrolyte of 1.2 M LiFSI in ethylene carbonate (EC) and ethyl methyl carbonate (EMC) mixed solvents. The electrochemical results shows that the corrosion current of aluminum is enhanced by cycling time and potential, which is correlated with the surface species and morphology. The formation of AlF 3 , which is induced by deep penetration of F − anions through surface passivation film, leads to internal volume change and the surface crack in the end. Our work will be inspiring for future development of high-energy-density and high-power-density lithium-ion batteries in which the LiFSI salt will be intensively used.