Electrolyte and electrochemical device

An electrochemical device, comprising a positive electrode, a negative electrode, and an electrolyte, wherein

• the electrolyte comprises a compound of Formula I and an additive A,
• wherein:
• R1, R2, R3, R4, R5, R6, R7 and R8 are each independently selected from:
• hydrogen, halo, —COOX, substituted or unsubstituted C1-8alkyl, substituted or unsubstituted C2-10alkenyl, substituted or unsubstituted C2-10alkynyl, substituted or unsubstituted C1-8alkoxy, or —Ra—S(═O)2—Rb, wherein Ra is selected from substituted or unsubstituted C1-8 alkylene, Rb is selected from halo or substituted or unsubstituted C1-8alkyl, and at least one of R1, R2, R3, R4, R5, R6, R7 and R8 is —COOX,
• wherein when substituted, the substituent is selected from cyano or halo;
• and
• X is selected from Li+, Na+, K+ or Rb+,
• wherein the additive A is at least one selected from fluoroethylene carbonate, LiPO2F2, or vinylene carbonate,
• wherein the electrolyte further comprises a compound of Formula III,
• the compound of Formula III is 0.1% to 20% based on a total weight of the electrolyte, and
• the compound of Formula III comprises at least one of:

An electronic device, comprising an electrochemical device, wherein the electrochemical device comprises a positive electrode, a negative electrode, and an electrolyte, wherein

• the electrolyte comprises a compound of Formula I and an additive A,
• wherein:
• R1, R2, R3, R4, R5, R6, R7 and R8 are each independently selected from:
• hydrogen, halo, —COOX, substituted or unsubstituted C1-8alkyl, substituted or unsubstituted C2-10alkenyl, substituted or unsubstituted C2-10alkynyl, substituted or unsubstituted C1-8alkoxy, or —Ra—S(═O)2—Rb, wherein Ra is selected from substituted or unsubstituted C1-8 alkylene, Rb is selected from halo or substituted or unsubstituted C1-8alkyl, and at least one of R1, R2, R3, R4, R5, R6, R7 and R8 is —COOX,
• wherein when substituted, the substituent is selected from cyano or halo;
• and
• X is selected from Li+, Na+, K+ or Rb+,
• wherein the additive A is at least one selected from fluoroethylene carbonate, LiPO2F2, or vinylene carbonate,
• wherein the electrolyte further comprises a compound of Formula III,
• the compound of Formula III is 0.1% to 20% based on a total weight of the electrolyte, and
• the compound of Formula III comprises at least one of: