Electrode for lithium secondary battery
View Patent ↗Disclosed is a method for forming an electrode comprising a protective layer, which comprises: dispersing or dissolving an aliphatic nitrile compound into a solvent to provide a coating solution; coating a surface of the electrode with the coating solution, said electrode having an electrode active material coated thereon; and removing the solvent used in the coating solution by drying to form a protective layer comprising an aliphatic nitrile compound-electrode active material complex.
1. A method for forming an electrode comprising a protective layer, which comprises:
dispersing or dissolving an aliphatic nitrile compound into a solvent to provide a coating solution;
coating a surface of the electrode with the coating solution, said electrode having an electrode active material coated thereon; and
removing the solvent used in the coating solution by drying to form a protective layer comprising an aliphatic nitrile compound-electrode active material complex.
2. The method according to claim 1 , wherein the aliphatic nitrile compound is an aliphatic dinitrile compound.
3. The method according to claim 1 , wherein the aliphatic nitrile compound is represented by the following formula 1:
wherein R is C2-C15 alkylene.
4. The method according to claim 1 , wherein the aliphatic nitrile compound is selected from the group consisting of succinonitrile, glutaronitrile, aponitrile, pimelonitrile, octanedinitrile, azelonitrile, sebaconitrile, 1,9-dicyanononane and dodecanedinitrile.
5. The method according to claim 1 , wherein the protective layer comprises a ligand-metal bond between the electrode active material and the aliphatic nitrile compound.
6. The method according to claim 1 , wherein the coating method is performed by dip coating or spray coating.
7. The method according to claim 1 , wherein the solvent is selected from the group consisting of acetone, THF (tetrahydrofuran), NMP (N-methyl-2-pyrrolidone) and carbonate solvent.
8. The method according to claim 7 , wherein the solvent is a carbonate solvent selected from the group consisting of ethylene carbonate, propylene carbonate, gamma-butyrolactone, diethyl carbonate, dimethyl carbonate, and ethylmethyl carbonate.
9. The method according to claim 1 , wherein the drying step is performed at a controlled temperature of between 90° C. and 110° C.
10. The method according to claim 1 , wherein the drying step is performed at a controlled drying rate of 3 m/min or less under a controlled vent flow of 2000-3000 rpm.
11. The method according to claim 1 , wherein the electrode is treated at a high temperature of 30° C.-90° C. before or after assemblage of a battery.
12. The method according to claim 1 , wherein the electrode active material comprises an oxide of a transition metal of the electrode active material.
13. The method according to claim 1 , wherein the aliphatic nitrile compound is present in an amount of 1 to 10 weight percent, based on the total weight of the electrode active material.
14. The method according to claim 1 , wherein the aliphatic nitrile compound is present in an amount of 1 to 5 weight percent, based on the total weight of the electrode active material.
15. The method according to claim 1 , wherein the aliphatic nitrile compound is present in an amount of 1 to 2.5 weight percent, based on the total weight of the electrode active material.
16. The method according to claim 1 , wherein the aliphatic nitrile compound is present in an amount of 1 to 20 weight percent, based on the total weight of electrolyte present in a battery.
17. The method according to claim 1 , wherein the aliphatic nitrile compound is used in the range of between 1:9 and 9:1, expressed in the weight ratio to the solvent.
18. A lithium secondary battery comprising an electrode prepared by the method of claim 1 as a cathode.