Journal Article Li metal battery Li-ion batteries copper fluoride cross-link effect electrofluorochromism extreme electrolyte high energy density high-voltage LiCoO2 cathodes high‐voltage cathode hydroxylated copper fluoride inorganic SEI inorganic-rich cathode electrolyte interphase lightweight electrolyte lithium‐ion battery moisture‐tolerance nonflammable electrolytes novel salt proton-coupled electron transfer reversible electroacid/base single-crystalline cathodes single-pixel RGB devices sodium alginate sulfurized polyacrylonitrile