Additives for non-aqueous electrolytes and electrochemical device using the same
View Patent ↗Disclosed is an electrolyte for batteries, which comprises: (a) an electrolyte salt; (b) an electrolyte solvent; and (c) a sulfonate-based compound containing at least one electron withdrawing group (EWG) selected from the group consisting of a cyano group (—CN), an isocyanate group (—NCO), a thiocyanate group (—SCN) and an isothiocyanate group (—NCS). An electrode comprising the sulfonate-based compound or a chemical reaction product thereof, partially or totally formed on the surface thereof, and an electrochemical device comprising the electrolyte and/or the electrode are also disclosed. The electrochemical device using the sulfonate-based compound containing a cyano group, an isocyanate group, a thiocyanate group and/or an isothiocyanate group as an additive for electrolytes can provide significantly improved high-temperature lifespan characteristics.
1. An electrolyte for batteries, which comprises:
(a) an electrolyte salt;
(b) an electrolyte solvent; and
(c) a sulfonate-based compound containing at least one electron withdrawing group (EWG) selected from the group consisting of a cyano group (—CN), an isocyanate group (—NCO), a thiocyanate group (—SCN) and an isothiocyanate group (—NCS), wherein the sulfonate-based compound is a compound represented by the following Formula I:
wherein R 1 is a C2˜C10 alkenyl; and R 2 is a functional group selected from the group consisting of a C1˜C10 alkyl group, alkenyl group, aryl group and phenyl group containing at least one substituent selected from a cyano group, an isocyanate group, a thiocyanate group and an isothiocyanate group.
2. The electrolyte according to claim 1 , wherein the sulfonate-based compound performs an electrochemical reaction in the battery to form a passivation layer, and shows a decreased reduction potential due to the electron withdrawing group (EWG) introduced thereto.
3. The electrolyte according to claim 1 , wherein the sulfonate-based compound is used in an amount of 0.1˜10 parts by weight based on 100 parts by weight of the electrolyte.
4. An electrochemical device comprising a cathode, an anode, a separator, and the electrolyte as defined in claim 1 , the electrolyte comprises:
(a) an electrolyte salt;
(b) an electrolyte solvent; and
(c) a sulfonate-based compound containing at least one electron withdrawing group (EWG) selected from the group consisting of a cyano group (—CN), an isocyanate group (—NCO), a thiocyanate group (—SCN) and an isothiocyanate group (—NCS), wherein the sulfonate-based compound is a compound represented by the following Formula I:
wherein R1 is a C2˜C10 alkenyl; and R 2 is a functional group selected from the group consisting of a C1˜C10 alkyl group, alkenyl group, aryl group and phenyl group containing at least one substituent selected from a cyano group, an isocyanate group, a thiocyanate group and an isothiocyanate group.
5. The electrochemical device according to claim 4 , wherein the sulfonate-based compound performs an electrochemical reaction in the battery to form a passivation layer, and shows a decreased reduction potential due to the electron withdrawing group (EWG) introduced thereto.
6. The electrochemical device according to claim 4 , which is a lithium secondary battery.
7. An electrode comprising a sulfonate-based compound or a chemical reaction product thereof, partially or totally formed on a surface thereof, wherein the sulfonate-based compound contains at least one electron withdrawing group (EWG) selected from a cyano group, an isocyanate group, a thiocyanate group and an isothiocyanate group, wherein the sulfonate-based compound is a compound represented by the following Formula I:
wherein R1 is a C2˜C10 alkenyl; and R 2 is a functional group selected from the group consisting of a C1˜C10 alkyl group, alkenyl group, aryl group and phenyl group containing at least one substituent selected from a cyano group, an isocyanate group, a thiocyanate group and an isothiocyanate group.
8. The electrode according to claim 7 , which comprises a sold electrolyte interface (SEI) film partially or totally formed on the surface thereof via electrochemical reduction of the sulfonate-based compound.
9. The electrode according to claim 7 , which comprises a complex-like protection layer formed via chemical bonding between a surface of an electrode active material and at least one substituent, contained in the sulfonate-based compound and selected from a cyano group, an isocyanate group, a thiocyanate group and an isothiocyanate group.
10. An electrochemical device comprising a cathode, an anode, a separator and an electrolyte, wherein either or both of the cathode and the anode are the electrodes as defined in claim 6 , the electrode comprises a sulfonate-based compound or a chemical reaction product thereof, partially or totally formed on a surface thereof, wherein the sulfonate-based compound contains at least one electron withdrawing group (EWG) selected from a cyano group, an isocyanate group, a thiocyanate group and an isothiocyanate group, wherein the sulfonate-based compound is a compound represented by the following Formula I:
wherein R1 is a C2˜C10 alkenyl; and
R 2 is a functional group selected from the group consisting of a C1˜C10 alkyl group, alkenyl group, aryl group and phenyl group containing at least one substituent selected from a cyano group, an isocyanate group, a thiocyanate group and an isothiocyanate group.
11. The electrochemical device according to claim 10 , wherein the electrode comprises a sold electrolyte interface (SEI) film partially or totally formed on the surface thereof via electrochemical reduction of the sulfonate-based compound.
12. The electrochemical device according to claim 10 , wherein the electrode comprises a complex-like protection layer formed via chemical bonding between a surface of an electrode active material and at least one substituent, contained in the sulfonate-based compound and selected from a cyano group, an isocyanate group, a thiocyanate group and an isothiocyanate group.