Electrolyte and electrochemical device

1. An electrolyte, comprising a dinitrile compound, a trinitrile compound, and propyl propionate, wherein, based on a total weight of the electrolyte, a weight percentage of the dinitrile compound is X and a weight percentage of the trinitrile compound is Y, where X and Y meet conditions represented by Formula (1) and Formula (2):

about 2 wt %≤( X+Y )≤about 11 wt %   (1); and

about 0.1≤( X/Y )≤about 8   (2),

wherein, based on the total weight of the electrolyte, a weight percentage of the propyl propionate is Z, where Y and Z meet a condition represented by Formula (3):

about 0.01≤( Y/Z )≤about 0.3   (3).

2. The electrolyte according to claim 1 , wherein the dinitrile compound comprises a compound of Formula (4) or (5):

CN—R 1 —CN (4);

CN—R 2 —(O—R 3 ) n —O—R 4 —CN (5);

or a combination thereof,

where R 1 , R 2 , R 3 and R 4 are each independently an alkylene group having 1-5 carbon atoms or an alkenylene group having 2-5 carbon atoms,

and n represents an integer from 0 to 5.

3. The electrolyte according to claim 1 , wherein the dinitrile compound is one selected from the group consisting of butanedinitrile, glutaronitrile, adiponitrile, 1,5-dicyanopentane, 1,6-dicyanohexane, 1,7-dicyanoheptane, 1,8-dicyanooctane, 1,9-dicyanononane, 1,10-dicyanodecane, 1,12-dicyanododecane, tetramethylbutanedinitrile, 2-methylglutaronitrile, 2,4-dimethylglutaronitrile, 2,2,4,4-tetramethylglutaronitrile, 1,4-dicyanopentane, 2,6-dicyanoheptane, 2,7-dicyanooctane, 2,8-dicyanononane, 1,6-dicyanodecane, 1,2-dicyanobenzene, 1,3-dicyanobenzene, 1,4-dicyanobenzene, 3,5-dioxa-pimelonitrile, 1,4-bis(cyanoethoxy)butane, ethylene glycol bis(2-cyanoethyl)ether, diethylene glycol bis(2-cyanoethyl)ether, triethylene glycol bis(2-cyanoethyl)ether, tetraethylene glycol bis(2-cyanoethyl)ether, 3,6,9,12,15,18-hexaoxaeicosanoic dinitrile, 1,3-bis(2-cyanoethoxy)propane, 1,4-bis(2-cyanoethoxy)butane, 1,5-bis(2-cyanoethoxy)pentane, ethylene glycol bis(4-cyanobutyl)ether, 1,4-dicyano-2-butene, 1,4-dicyano-2-methyl-2-butene, 1,4-dicyano-2-ethyl-2-butene, 1,4-dicyano-2,3-dimethyl-2-butene, 1,4-dicyano-2,3-diethyl-2-butene, 1,6-dicyano-3-hexene, 1,6-dicyano-2-methyl-3-hexene, 1,6-dicyano-2-methyl-5-methyl-3-hexene, and any combination thereof.

4. The electrolyte according to claim 1 , wherein the trinitrile compound comprises a compound of Formula (6) or (7):

or a combination thereof,

where in Formula (6), x, y, and z represent an integer from 0 to 5, and x, y, and z are not 0 at the same time; and

in Formula (7), R 5 represents hydrogen or an alkyl group having 1-5 carbon atoms, R 6 , R 7 and R 8 are each independently an alkylene group having 1-5 carbon atoms, and X 4 , X 5 and X 6 are each independently —R 9 —CN, in which R 9 represents an alkylene group having 1-5 carbon atoms.

5. The electrolyte according to claim 1 , wherein the trinitrile compound is one selected from the group consisting of: 1,3,5-pentanetricarbonitrile; 1,2,3-propanetrinitrile; 1,3,6-hexanetricarbonitrile; 1,2,6-hexanetricarbonitrile; 1,2,3-tris(2-cyanoethoxy)propane; 1,2,4-tris(2-cyanoethoxy)butane; 1,1,1-tris(cyanoethoxymethylene)ethane; 1,1,1-tris(cyanoethoxymethylene)propane; 3-methyl-1,3,5-tris(cyanoethoxy)pentane; 1,2,7-tris(cyanoethoxy)heptane; 1,2,6-tris(cyanoethoxy)hexane; 1,2,5-tris(cyanoethoxy)pentane; and any combination thereof.

6. The electrolyte according to claim 1 , wherein X is about 0.01-10 wt %, Y is about 0.01-10 wt %, and a weight percentage Z of the propyl propionate is about 5-50 wt %.

7. The electrolyte according to claim 1 , further comprising a fluoroether comprising at least one of the compounds of Formula (8), Formula (9), Formula (10) or Formula (11):

Rf1-O-Rf2  (8);

Rf1-O—R  (9);

Rf1-O—(R′—O) n -Rf2  (10); and

Rf1-O—(R′—O) n —R  (11),

wherein Formulae (8), (9), (10), and (11), Rf1 and Rf2 are each independently a linear or branched C 1 to C 12 fluoroalkyl group having at least one hydrogen atom substituted with fluoro, R is a linear or branched C 1 to C 12 alkyl group, and R′ is a linear or branched C 1 to C 5 alkylene group, and n is an integer from 1 to 5.

8. The electrolyte according to claim 7 , wherein Rf1 or Rf2 is each independently a fluoroalkyl group selected from the group consisting of HCF 2 —, CF 3 —, HCF 2 CF 2 —, CH 3 CF 2 —, CF 3 CH 2 —, CF 3 CF 2 —, (CF 3 ) 2 CH—, HCF 2 CF 2 CH 2 —, CF 3 CH 2 CH 2 —, HCF 2 CF 2 CF 2 CH 2 —, HCF 2 CF 2 CF 2 CF 2 CH 2 —, CF 3 CF 2 CH 2 —, CF 3 CFHCF 2 CH 2 —, HCF 2 CF(CF 3 )CH 2 —, and CF 3 CF 2 CH 2 CH 2 —.

9. The electrolyte according to claim 7 , wherein the fluoroether is one selected from the group consisting of: HCF 2 CF 2 CH 2 OCF 2 CF 2 H, (CF 3 ) 2 CFCF(CF 2 CF 3 )(OCH 3 ), CF 3 CHFCF 2 CH(CH 3 )OCF 2 CHFCF 3 , HCF 2 CF 2 CH 2 OCF 2 CF 2 CF 2 CF 2 H, HCF 2 CF 2 OCH 2 CF 3 , HCF 2 CF 2 OCH 2 CH 2 OCF 2 CF 2 H, HCF 2 CF 2 OCH 2 CH 2 CH 2 OCF 2 CF 2 H, HCF 2 CF 2 CH 2 OCF 2 CF 2 CF 2 H, HCF 2 CF 2 OCH 2 CH 2 OCF 2 CF 2 CF 2 H, HCF 2 CF 2 OCH 2 CH 2 CH 2 OCF 2 CF 2 CF 2 H, CH 3 OCH 2 CH 2 OCH 2 CH 2 F, CH 3 OCH 2 CH 2 OCH 2 CF 3 , CH 3 OCH 2 CH(CH 3 )OCH 2 CH 2 F, CH 3 OCH 2 CH(CH 3 )OCH 2 CF 3 , FCH 2 CH 2 OCH 2 CH 2 OCH 2 CH 2 F, FCH 2 CH 2 OCH 2 CH(CH 3 )OCH 2 CH 2 F, CF 3 CH 2 O(CH 2 CH 2 O) 2 CH 2 CF 3 , CF 3 CH 2 OCH 2 CH(CH 3 )OCH 2 CF 3 , and any combination thereof.

10. The electrolyte according to claim 1 , further comprising a cyclic phosphonic anhydride, based on the total weight of the electrolyte, a content of cyclic phosphonic anhydride is about 0.01-10 wt %.

11. The electrolyte according to claim 1 , further comprising one selected from a group consisting of: a cyclic carbonate ester having a carbon-carbon double bond, a fluorinated chain carbonate ester, a fluorinated cyclic carbonate ester, a compound having a sulfur-oxygen double bond, and any combination thereof.

12. The electrolyte according to claim 1 , further comprising a cyclic carboxylate ester, including γ-butyrolactone or γ-valerolactone or a combination thereof.

13. An electrochemical device, wherein the electrochemical device comprises electrodes and an electrolyte comprising a dinitrile compound, a trinitrile compound, and propyl propionate, wherein, based on the total weight of the electrolyte, the weight percentage of the dinitrile compound is X and the weight percentage of the trinitrile compound is Y, where X and Y meet the conditions represented by Formula (1) and Formula (2):

about 2 wt %≤( X+Y )≤about 11 wt %   (1); and

about 0.1≤( X/Y )≤about 8   (2).

14. The electrochemical device according to claim 13 , wherein the electrode comprises a current collector and a coating on the current collector, the coating comprising a single-sided coating and a double-sided coating, wherein:

the single-sided coating is a coating formed by applying a slurry on one surface of the current collector; and the double-sided coating is a coating formed by applying a slurry on two opposite surfaces of the current collector; and

the electrode with the single-sided coating has an electrode compaction density D1, and the electrode with the double-sided coating has an electrode compaction density D2, wherein D1 and D2 meet the relationship: about 0.8≤D1/D2≤about 1.2.

15. The electrochemical device according to claim 14 , wherein the electrode s comprise a cathode and a anode, wherein when the electrode is a cathode, 3.5 g/cm 3 ≤D2≤4.3 g/cm 3 ; or when the electrode is an anode, 1.2 g/cm 3 ≤D2≤1.8 g/cm 3 .

16. An electronic device, comprising an electrochemical device that includes electrodes and an electrolyte comprising a dinitrile compound, a trinitrile compound, and propyl propionate, wherein, based on the total weight of the electrolyte, the weight percentage of the dinitrile compound is X and the weight percentage of the trinitrile compound is Y, where X and Y meet the conditions represented by Formula (1) and Formula (2):

about 2 wt %≤( X+Y )≤about 11 wt %   (1); and

about 0.1≤( X/Y )≤about 8   (2).