Does fec have plasticizing effect?

yes. Fluoroethylene carbonate (FEC) is an excellent film-forming additive for electrolyte cathode. It can react with lithium salt in lithium battery electrolyte to produce lithium fluoride (LiF) which is difficult to decompose, thus forming a uniform, dense, low-impedance and elastic solid electrolyte interface film (SEI film), which can effectively inhibit the growth of lithium dendrites and has plasticizing effect.