POSITIVE ELECTRODE SHEET AND SECONDARY BATTERY INCLUDING POSITIVE ELECTRODE SHEET
A positive electrode sheet includes a positive electrode current collector and a positive electrode film disposed on at least one surface of the positive electrode current collector and including an additive. The additive includes a structural unit made from acrylonitrile and a structural unit made from a monomer represented by following formula: where R 1 , R 2 , R 3 , and R 4 are each independently selected from hydrogen, an alkyl group with 1-8 carbon atoms, or a saturated carboxylic acid group with 1-8 carbon atoms, and at least one of R 1 , R 2 , R 3 , or R 4 is selected from the saturated carboxylic acid group with 1-8 carbon atoms.
1 . A positive electrode sheet, comprising:
a positive electrode current collector; and
a positive electrode film disposed on at least one surface of the positive electrode current collector and comprising an additive, wherein the additive comprises a structural unit made from acrylonitrile and a structural unit made from a monomer represented by following formula:
wherein R 1 , R 2 , R 3 , and R 4 are each independently selected from hydrogen, an alkyl group with 1-8 carbon atoms, or a saturated carboxylic acid group with 1-8 carbon atoms, and at least one of R 1 , R 2 , R 3 , or R 4 is selected from the saturated carboxylic acid group with 1-8 carbon atoms.
2 . The positive electrode sheet according to claim 1 , wherein a total number of carbon atoms in the monomer is in a range of 3-10.
3 . The positive electrode sheet according to claim 1 , wherein a weight proportion of the structural unit made from the monomer in the additive is in a range of 60-85%.
4 . The positive electrode sheet according to claim 3 , wherein the weight proportion of the structural unit made from the monomer in the additive is in a range of 65-75%.
5 . The positive electrode sheet according to claim 1 , wherein a weight-average molecular weight of the additive is in a range of 500-100,000.
6 . The positive electrode sheet according to claim 5 , wherein the weight-average molecular weight of the additive is in a range of 2,000-50,000.
7 . The positive electrode sheet according to claim 1 , wherein a weight proportion of the additive in the positive electrode film is in a range of 0.01-2% based on a total weight of the positive electrode film.
8 . The positive electrode sheet according to claim 7 , wherein the weight proportion of the additive in the positive electrode film is in a range of 0.02-1.5% based on the total weight of the positive electrode film.
9 . The positive electrode sheet according to claim 1 , wherein:
the additive is a first additive; and
the positive electrode film further comprises a second additive, the second additive being a vinylidene fluoride modified polymer having a vinylidene fluoride main chain and a C 3 -C 10 unsaturated carboxylic acid group grafted on the vinylidene fluoride main chain.
10 . The positive electrode sheet according to claim 9 , wherein a weight proportion of the C 3 -C 10 unsaturated carboxylic acid group in the second additive is less than or equal to 1%.
11 . The positive electrode sheet according to claim 10 , wherein the weight proportion of the C 3 -C 10 unsaturated carboxylic acid group in the second additive is in a range of 0.5-1%.
12 . The positive electrode sheet according to claim 9 , wherein a weight-average molecular weight of the second additive is in a range of 800,000-1500,000.
13 . The positive electrode sheet according to claim 9 , wherein a weight proportion of the second additive in the positive electrode film is less than or equal to 3.5% based on a total weight of the positive electrode sheet.
14 . The positive electrode sheet according to claim 13 , wherein the weight proportion of the second additive in the positive electrode film is less than or equal to 2.5% based on the total weight of the positive electrode sheet.
15 . The positive electrode sheet according to claim 1 , wherein:
the positive electrode film further comprises a lithium-rich additive represented by following formula:
Li x M y R k
wherein x>0, y≥0, k>0, and x, y, k are selected such that the lithium-rich additive is electrically neutral;
M is selected from a transition metal; and
R is selected from one of S, N, O, F.
16 . The positive electrode sheet according to claim 15 , wherein the lithium-rich additive is selected LiNiO 2 , Li 2 NiO 2 , LiCoO 4 , Li 6 CoO 4 , Li 5 FeO 4 , Li 2 S, Li 3 N, Li 2 O, Li 2 O 2 , and LiF.
17 . The positive electrode sheet according to claim 15 , wherein a weight proportion of the lithium-rich additive in the positive electrode film is less than or equal to 15 wt %.
18 . A secondary battery comprising the positive electrode sheet according to claim 1 .
19 . A battery pack comprising the secondary battery according to claim 18 .
20 . A power consumption apparatus, comprising the second battery according to claim 18 .