SEPARATOR AND PREPARATION METHOD THEREOF, SECONDARY BATTERY AND DEVICE
The present application provides a separator and a preparation method thereof, a secondary battery, and a device. The separator includes a microporous layer; the microporous layer includes an alkali metal-containing polymer, the alkali metal-containing polymer includes a polymer chain, and the polymer chain includes a first group and a second group; (a) the first group is selected from an organic acid alkali metal group, an alcohol alkali metal group, or a combination thereof; (b) the second group is selected from an organic acid group; an alkali metal content in the first group is 50-100 ppm based on a total mass of the separator; and a hydrogen content in the second group is 10-50 ppm based on the total mass of the separator.
1 . A separator, comprising: a microporous layer, wherein the microporous layer comprises an alkali metal-containing polymer, the alkali metal-containing polymer comprises a polymer chain, and the polymer chain comprises a first group and a second group;
(a) the first group is selected from an organic acid alkali metal group, an alcohol alkali metal group, or a combination thereof;
(b) the second group is selected from an organic acid group;
an alkali metal content in the first group is 50-100 ppm based on a total mass of the separator; and
a hydrogen content in the second group is 10-50 ppm based on the total mass of the separator.
2 . The separator according to claim 1 , wherein a ratio of the alkali metal content in the first group to the hydrogen content in the second group is (1-10):1.
3 . The separator according to claim 1 , wherein the alkali metal-containing polymer has a weight average molecular weight of 100 to 5000.
4 . The separator according to claim 1 , wherein the polymer chain is selected from a poly olefin chain, a polyester chain, and a polyepoxy alkyl chain.
5 . The separator according to claim 2 , having one or more of the following features:
(1) the polyolefin chain comprising a polyphenylene olefin chain, a polynitrile olefin chain, or a combination thereof;
(2) the polyester chain comprising a polycarboxylate chain; and
(3) the polyepoxy alkyl chain comprising a polyalkyl ethylene glycol chain.
6 . The separator according to claim 1 , wherein the organic acid alkali metal group is selected from a carboxylic acid alkali metal group, a sulfonic acid alkali metal group, a nitric acid alkali metal group, a phosphate alkali metal group, a boric acid alkali metal group, or a combination thereof.
7 . The separator according to claim 1 , wherein the organic acid group is selected from a carboxylic acid group, a sulfonic acid group, a nitric acid group, a phosphoric acid group, a boric acid group, or a combination thereof.
8 . The separator according to claim 1 , wherein one polymer chain comprises an end group and a side chain group, one or more of the side chain groups being the first group, one or more of the end groups being the second group.
9 . The separator according to claim 1 , wherein the alkali metal-containing polymer has a crosslinking agent group, and the crosslinking agent group accounts for 0.1-10% of a total mass of the alkali metal-containing polymer.
10 . The separator according to claim 1 , wherein the alkali metal-containing polymer is a free radical polymer.
11 . The separator according to claim 1 , wherein the alkali metal is selected from lithium, sodium, or potassium.
12 . The separator according to claim 1 , wherein the polymer chain is expressed by a formula:
wherein R is a C 0-10 group, —IO 1 Li is the first group, and —IO 1 H is the second group; and
wherein x=1-10, y=0-10, and z=1-10.
13 . The separator according to claim 12 , wherein R comprises one or more of an aromatic group, an oxygen-containing group, and a nitrogen-containing group.
14 . The separator according to claim 12 , characterized by one or more of the following:
(1) R being phenyl or substituted phenyl, amide, or hydroxy;
(2) —IO1Li being —SO 3 Li, —NO 2 Li, —PO 3 Li or —BO 2 Li or —OLi; and
(3) —IO 1 H being —SO 3 H, —NO 2 H, —PO 3 H or —BO 2 H.
15 . The separator according to claim 1 , wherein the microporous layer comprises a microporous matrix layer and a modified film, the modified film covering at least part of a surface of the microporous matrix layer, the modified film having the alkali metal-containing polymer.
16 . The separator according to claim 1 , wherein the modified film has a thickness of 1-100 nanometers.
17 . A preparation method of a separator for a battery, comprising:
providing a microporous matrix layer; and
forming a modified film on at least part of a surface of the microporous matrix layer,
wherein the modified film has an alkali metal-containing polymer, the alkali metal-containing polymer comprises a polymer chain, and the polymer chain comprises a first group and a second group;
(a) the first group is selected from an organic acid alkali metal group, an alcohol alkali metal group, or a combination thereof;
(b) the second group is selected from an organic acid group;
an alkali metal content in the first group is 50-100 ppm based on a total mass of the separator; and
a hydrogen content in the second group is 10-50 ppm based on the total mass of the separator.
18 . A secondary battery, comprising the separator according to claim 1 .
19 . A device, comprising the secondary battery according to claim 18 .