Electrolyte and electrochemical device
Energy storage materials, and specifically, an electrolyte and an electrochemical device, where the electrolyte includes an additive A and an additive B, the additive A is selected from multi-cyano six-membered N-heterocyclic compounds represented by Formula I-1, Formula I-2 and Formula I-3, and combinations thereof, and the additive B is at least one sulfonate compound. The electrochemical device includes the above electrolyte. The electrolyte can effectively passivate surface activity of the positive electrode material, inhibit oxidation of the electrolyte, and effectively reduce gas production of the battery, meanwhile the electrolyte can be adsorbed on catalytically active sites of the graphite surface to form a stable SEI film, thereby effectively reducing side reactions. The electrochemical device using the electrolyte has good high temperature and high voltage cycle performance and storage performance.
1. An electrolyte, comprising an additive A and an additive B, wherein the additive A is selected from a group consisting of multi-cyano six-membered N-heterocyclic compounds represented by Formula I-1 and Formula I-3, and combinations thereof:
wherein R 1 , R 2 , R 3 and R 4 are each independently selected from a group consisting of hydrogen, halogen, substituted or unsubstituted C 1 -C 12 alkyl, substituted or unsubstituted C 1 -C 12 alkoxy, substituted or unsubstituted C 1 -C 12 amine group, substituted or unsubstituted C 2 -C 12 alkenyl, substituted or unsubstituted C 2 -C 12 alkynyl, substituted or unsubstituted C 6 -C 26 aryl, and substituted or unsubstituted C 4 -C 12 heterocyclic group;
a substituent for the above groups, if present, is independently selected from a group consisting of halogen, cyano, C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 1 -C 6 alkoxy, and combinations thereof;
x, y and z are each an integer independently selected from 0-8; and
m, n and k are each an integer independently selected from 0-2; and
wherein the additive B is at least one sulfonate compound.
2. The electrolyte according to claim 1 , wherein
R 1 , R 2 , R 3 and R 4 are each independently selected from a group consisting of hydrogen, halogen, substituted or unsubstituted C 1 -C 3 linear or branched alkyl, substituted or unsubstituted C 5 -C 7 cycloalkyl, substituted or unsubstituted C 1 -C 3 alkoxy, substituted or unsubstituted C 1 -C 3 amine group, substituted or unsubstituted C 2 -C 3 alkenyl, substituted or unsubstituted C 2 -C 3 alkynyl, substituted or unsubstituted C 6 -C 8 aryl, and substituted or unsubstituted C 4 -C 7 heterocyclic group, wherein a substituent for the above groups, if present, is halogen.
3. The electrolyte according to claim 1 , wherein
in Formula I-1, R 1 and R 3 are identical; and
in Formula I-3, at least two of R 1 , R 2 and R 3 are identical.
4. The electrolyte according to claim 3 , wherein
in Formula I-1, R 1 , R 3 and R 4 are identical.
5. The electrolyte according to claim 3 , wherein
in Formula I-1, R 1 and R 3 are hydrogen; and
in Formula I-3, at least two of R 1 , R 2 and R 3 are hydrogen.
6. The electrolyte according to claim 5 , wherein
in Formula I-1, R 1 , R 3 and R 4 are hydrogen.
7. The electrolyte according to claim 1 , wherein the additive A is from 0.001% to 10% by weight of the electrolyte.
8. The electrolyte according to claim 1 , wherein the multi-cyano six-membered N-heterocyclic compound represented by Formula I-1 is selected from a group consisting of the following compounds and combinations thereof:
and
the multi-cyano six-membered N-heterocyclic compound represented by Formula I-3 is selected from a group consisting of the following compounds and combinations thereof:
9. The electrolyte according to claim 1 , wherein the at least one sulfonate compound is selected from a group consisting of a sultone compound, a disulfonate compound, and combinations thereof,
wherein the sultone compound is selected from a group consisting of compounds represented by Formula II-1, and combinations thereof,
wherein R 21 is selected from substituted or unsubstituted C 1 -C 6 alkylene, and substituted or unsubstituted C 2 -C 6 alkenylene, wherein a substituent for the above groups, if present, is halogen, C 1 -C 3 alkyl, or C 2 -C 4 alkenyl; and
wherein the disulfonate compound is selected from a group consisting of compounds represented by Formula II-2, and combinations thereof,
wherein R 22 , R 23 , R 24 and R 25 are each independently selected from hydrogen, halogen, substituted or unsubstituted C 1 -C 10 alkyl, and substituted or unsubstituted C 2 -C 10 alkenyl, wherein Ma a substituent for the above groups, if present, is halogen, C 1 -C 3 alkyl, or C 2 -C 4 alkenyl.
10. The electrolyte according to claim 1 , wherein the additive B is from 0.1% to 10% by weight of the electrolyte.
11. The electrolyte according to claim 1 , wherein the electrolyte further comprises an additive C, and the additive C is at least one unsaturated bond-containing cyclic carbonate compound.
12. The electrolyte according to claim 11 , wherein the unsaturated bond-containing cyclic carbonate compound is selected from a group consisting of compounds represented by Formula III and combinations thereof:
wherein R 31 is selected from alkenyl-substituted C 1 -C 6 alkylene, and substituted or unsubstituted C 2 -C 6 alkenylene, wherein a substituent for the above groups, if present, is selected from a group consisting of halogen, C 1 -C 6 alkyl, C 2 -C 6 alkenyl, and combinations thereof.
13. The electrolyte according to claim 11 , wherein the additive C is from 0.1% to 10% by weight of the electrolyte.
14. The electrolyte according to claim 11 , wherein the additive C is from 0.5% to 5% by weight of the electrolyte.
15. The electrolyte according to claim 1 , wherein m, n and k are each independently 1 or 2.
16. The electrolyte according to claim 1 , wherein the additive A is from 0.01% to 6% by weight of the electrolyte.
17. The electrolyte according to claim 1 , wherein the additive B is from 0.5% to 7% by weight of the electrolyte.
18. An electrochemical device, comprising a positive electrode plate, a negative electrode plate, a separator positioned between the positive electrode plate and the negative electrode plate, and an electrolyte according to claim 1 .
19. The electrochemical device according to claim 18 , wherein the electrochemical device is a lithium-ion secondary battery, a lithium primary battery, or a lithium-ion capacitor.
20. The electrochemical device according to claim 18 , wherein the electrochemical device is a lithium-ion secondary battery, and the lithium-ion secondary battery has a charge cut-off voltage no less than 4.2V.