Osteoporosis Failure of Aluminum Current Collector Induced Crosstalk Degradation at the Imide-Type Lithium Salt Comprised Practical-Level Lithium-Ion Batteries

Abstract

The atypical failure mechanism caused by the inclusion of lithium bis(fluorosulfonyl)imide (LiFSI) salt in lithium-ion batteries (LIB) is elucidated. When subjected to elevated temperature cycling, the LiFSI salt triggers the degradation of the aluminum current collector, leading to the dissolution of Al ions into the electrolyte. These dissolved Al ions then migrate toward the negative electrode surface where they spontaneously reduce and form Al deposits due to the low electrode potential. This Al deposition further catalyzes the cathodic decomposition of the electrolyte, impacting the interphasial resistance of the negative electrode and consuming both Li ions and electrolyte components. Upon extended cycling with LiFSI-containing electrolytes, a notable decline in the reversible capacity of LIB becomes evident due to cross-talk failure resulting from Al current collector corrosion. Consequently, to enhance the cycling performance of LIBs using LiFSI-based electrolytes, it is necessary to simultaneously prevent Al corrosion and subsequent deposition on the surface of the negative electrode.