Elucidating critical origin for capacity fading in High-voltage coin cell with FSI-based electrolyte

•Stainless-steel (SS) coin-cell parts are more vulnerable to corrosion than the Al.•SS degradation can accelerate the corrosion of Al current collectors.•Galvanic electron transfer from Al to SS can corrode the Al metal.•MD simulations verify SS and Al’s corrosion mechanisms in the imide electrolyte.•SS and Al-free pouch cells with carbon current collector show improved cyclability.