An electrolyte is provided, which includes (a) 100 parts by weight of oxide-based solid state inorganic electrolyte, (b) 20 to 70 parts by weight of [Li(—OR1)n−OR2]Y, wherein R1 is C1-4 alkylene group, R2 is C1-4 alkyl group, n is 2 to 100, and Y is PF6−, BF4−, AsF6−, SbF6−, ClO4−, AlCl4−, GaCl4−, NO3−, C(SO2CF3)3−, N(SO2CF3)2−, SCN−, CF3CF2SO3−, C6F5SO3−, CF3CO2−, SO3F−, B(C6H5)4−, CF3SO3−, or a combination thereof, (c) 1 to 10 parts by weight of nano oxide, and (d) 1 to 20 parts by weight of binder. The electrolyte can be disposed between a positive electrode and a negative electrode to form a battery.