ELECTROLYTE AND ELECTROCHEMICAL DEVICE

An electrolyte includes diglycolic anhydride and a trinitrile compound, with which the cycle performance and the high-temperature stability under over-discharge conditions of lithium-ion batteries are significantly improved. The electrolyte includes a compound of Formula I; and at least one of a compound of Formula II or a compound of Formula III; R, R, Rand Rare each independently selected from hydrogen, halo, substituted or unsubstituted C-Calkyl, substituted or unsubstituted C-Calkenyl, substituted or unsubstituted C-Calkynyl, substituted or unsubstituted C-Caryl, substituted or unsubstituted C-Calkoxy, or substituted or unsubstituted C-Caryloxy, wherein when substituted, the substituent is halo, cyano, or C-Calkyl; and a, d and f are each independently selected from an integer from 1 to 5, and b, c, e, g, h and i are each independently selected from an integer from 0 to 5.