An electrolyte is provided, which includes organic solvent; and (1) a compound and an ammonium salt thereof, (2) a diacid and an ammonium salt thereof, or (3) a combination thereof. The compound has a chemical structure of wherein R1 is C1-8 alkyl group, C alkenyl group, C1-8 alkynyl group, or aromatic group; and R2 is —(CnH2n)—OH, and n is an integer from 2 to 8. The diacid has a chemical structure of wherein R3 is C1-8 alkyl group, C1-8 alkenyl group, C1-8 alkynyl group, or aromatic group.