Lithium hexafluorophosphate (LiPF 6 ) is the standard lithium salt for the state-of-the-art commercial lithium ion batteries (LIBs). LiPF 6 is the obvious winner over other lithium salts due to the virtue of its higher ionic conductivity (~10 -2 Scm -1 at 25ºC), excellent anticorrosion nature toward aluminum, and good anodic stability (> 4.2V vs. Li/Li + ) .