Positive electrode sheet and lithium ion secondary battery with same

Abstract

The invention belongs to the technical field of lithium secondary batteries and discloses a positive electrode sheet preparation method and a lithium ion secondary battery with a positive electrode sheet. Prepared positive electrode sheet paste contains an additive in a molecular formula (1), and the additive can be phosphorous acid or phosphite ester. By adding of the appropriate quantity of phosphorous acid and/or phosphite ester into the positive electrode sheet paste, the problem of powder shedding of the positive electrode sheet can be improved, adhesiveness between a positive electrode sheet coating and an aluminum foil is improved, a positive electrode material particle coating effect is achieved, and accordingly battery gas-producing expansion is remarkably inhibited while batterycycle stability is improved.

Description

Technical field [0001] The present invention belongs to the technical field of lithium secondary batteries, relates to a positive electrode sheet and a lithium ion secondary battery containing the positive electrode sheet, and specifically relates to a nickel-rich ternary or layered lithium-rich manganese-based composite with high lithium insertion (de) lithium capacity A positive electrode sheet of an oxide lithium secondary battery and a lithium secondary battery including the positive electrode sheet. Background technique [0002] Compared with other secondary chemical power sources, lithium-ion batteries have the advantages of high energy density, low self-discharge rate, and excellent cycle stability, making their application fields from small power sources such as mobile communications and handheld computers to new energy vehicles and energy storage The development of large-capacity power supply represented by systems, etc., has a very broad market prospect. [0003] Among s...

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Problems solved by technology

Although water washing is very effective in reducing the residual alkali on the surface, it is easy to damage the surface structure of the material, and it is difficult to restore the subsequent heat treatment, resulting in poor electrical properties; the surface is coated with metal / non-metal oxides, especially those that form ionic conductors with lithium ions Oxide is also a good way to reduce the residual alkali on the surface of the above materials, but the effect is not obvious and it is difficult to achieve uniform coating, especially when there are micropores in the material particles, it is more difficult to achieve uniform coating, which is very important for reducing nickel-rich ternary or The effect of residual alkali on the surface of layered lithium-rich manganese-based material particles is not obvious, and often requires secondary sintering, which increases processing costs

[0009] Adding organic acid to the positive plate material slurry can only partially remove the residual alkali on the surface, and water will also be generated after the reaction between the acid and the alkali, which cannot completely solve the gel problem in the pulping process; it can also affect the bonding Modification of the agent itself, such as high-end Solvay PVDF5130 molecules generally introduce -COOH, -SO 3 Acidic functional groups such as H, for the same reason as adding organic acids above, this method can only alleviate the gel problem in the pulping process

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