The subject application relates to an electrochemical device including a cathode, an anode and an electrolyte. The cathode includes a fluoropolymer which has an X-ray diffraction spectrum with a diffraction peak in the range of 34°≤2θ≤38°. The electrolyte includes a compound having 2 to 3 cyano groups. The electrochemical device of the present application has excellent cycle and high temperature storage properties.