Abstract: A light-emitting device with high emission efficiency is provided. The light-emitting device includes an anode, a cathode, and an EL layer positioned between the anode and the cathode. The EL layer includes a light-emitting layer and an electron-transport layer; the light-emitting layer includes a light-emitting material; the electron-transport layer includes an organic compound having an electron-transport property and a metal complex of an alkali metal; the ordinary refractive index of the organic compound having an electron-transport property in a peak wavelength of light emitted from the light-emitting material is greater than or equal to 1.50 and less than or equal to 1.75; and the ordinary refractive index of the metal complex of an alkali metal in the peak wavelength of the light emitted from the light-emitting material is greater than or equal to 1.45 and less than or equal to 1.70.

Abstract: An electrolyte composition includes: a sulfonylimide compound represented by the following general formula (1) as an electrolyte salt; and an amidosulfuric acid component. LiN(X1SO2)(X2SO2)??(1) (where X1 and X2 are identical to or different from each other, and each represent a fluorine atom, an alkyl group with a carbon number of 1 to 6, or a fluoroalkyl group with a carbon number of 1 to 6).