The present invention provides an electrolyte containing novel additive for electrochemical device and the electrochemical device thereof. The additive is a compound represented by below formula (I): wherein R1 and R2 are independently hydrogen, methyl, ethyl, or halogen; n and m are independently 1, 2, or 3. The additive of the present invention can protect the surface of the carbonaceous material on the anode and suppress the occurrence of exfoliation, thereby increasing the lifetime of the electrochemical device. Furthermore, the additive of the present invention also slows down the decay of capacity on the cathode during charging-discharging cycles, and hence maintains a better performance.