Positive plate and lithium-ion battery

A lithium-ion battery, comprising:

• a negative electrode sheet,
• a non-aqueous electrolyte, and
• a positive electrode sheet comprising:
• a positive electrode current collector;
• and
• a positive electrode material layer formed on the positive electrode current collector,
• wherein the positive electrode material layer comprises a high-nickel positive electrode material represented by formula I and a compound represented by formula II:
• Li
• a
• ⁢
• Ni
• q
• ⁢
• Co
• y
• ⁢
• M
• z
• ⁢
• O
• 2
• Formula
• ⁢
• I
• where 0.9≤a≤1.2, 0.7≤q≤1, y≥0, z≥0, and q+y+z=1, wherein M is selected from one or both of Mn and Al;
• where R1, R2, and R3 are each independently selected from an alkyl group of 1 to 5 carbon atoms, a fluoroalkyl group of 1 to 5 carbon atoms, an ether group of 1 to 5 carbon atoms, a fluoroether group of 1 to 5 carbon atoms, an unsaturated hydrocarbonyl group of 2 to 5 carbon atoms, and at least one of R1, R2, and R3 is the unsaturated hydrocarbonyl group of 2 to 5 carbon atoms;
• wherein the positive electrode sheet satisfies following conditions:
• 0.05
• ≤
• (
• b
• /
• 10
• )
• *
• (
• h
• /
• x
• )
• ≤
• 15
• ;
• and
• 0.005
• ≤
• b
• ≤
• 1
• ,
• 0.7
• ≤
• x
• ≤
• 1
• ,
• 80
• ≤
• h
• ≤
• 140
• ;
• where b is a mass percent content of the compound represented by the formula II in the positive electrode material layer, in a unit of %;
• x is a molar ratio of Ni element:
• (Ni element+Co element+M element) in the high-nickel positive electrode material;
• and
• h is a thickness of the positive electrode material layer on one side of the positive electrode current collector, in a unit of μm;
• wherein a solution obtained after ultrasonically shaking the positive electrode sheet in a solvent is subjected to a liquid chromatography-mass spectrometer (LC-MS) analysis, and a characteristic peak appears in a region having a retention time of 6.5 min to 7.5 min.