Composite coating for improving high temperature performance of lithium ion battery, composite negative electrode sheet and preparation method thereof, lithium ion battery

Abstract

The invention discloses a composite coating for improving the high-temperature performance of a lithium-ion battery, a composite negative plate, a preparation method of the composite negative plate and the lithium-ion battery. The composite coating is mainly prepared from the following components in parts by mass: 0.5-2 parts of ionic liquid, 0.5-2 parts of lithium salt, 1-5 parts of modified graphene and 10-20 parts of binders, wherein the ionic liquid is brominated N-methyl-N-propyl piperidine. According to the composite coating for improving the high-temperature performance of the lithium-ion battery, a composite coating layer is prepared on the surface of the negative plate and serves as a negative electrode of the lithium-ion battery, the structural stability of an SEI (solid electrolyte interphase) film and electrolyte thereof can be improved by the ionic liquid under the condition of high temperature, the decomposition temperature of the SEI film under the condition of high temperature is increased, the lithium salt supplements lithium ions consumed in the forming process of the SEI film for the plate, heat diffusivity of the plate is improved by the aid of high conductivity and heat dispersion of the graphene, and circulation and storage properties of the lithium-ion battery under the condition of high temperature are finally improved.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a composite coating for improving the high temperature performance of lithium ion batteries, and also relates to a composite negative electrode sheet using the above composite coating and a preparation method thereof, and a lithium ion battery using the composite negative electrode sheet. Battery. Background technique [0002] Lithium-ion battery is a new type of energy storage battery developed in recent years, and is favored by people for its advantages such as good cycle life, high energy density, and environmental friendliness; there are many factors to evaluate the pros and cons of lithium-ion batteries, mainly including Energy density, low temperature performance, cycle performance, high temperature shelf performance, high temperature cycle performance. During use, due to the high temperature in summer, lithium-ion batteries need to operate safely...

AI Technical Summary

Problems solved by technology

The lithium-ion battery uses the lipophilic effect of the organic solvent in the electrolyte to better wet the organic polymer coating, thereby improving the contact effect between the electrolyte and the pole piece, and improving the cycle performance and high temperature resistance of the lithium-ion battery. However, the heat dissipation effect of the organic polymer itself is not good, and the high temperature resistance performance of the lithium-ion battery is limited, and it will also affect the heat dissipation performance of the pole piece material

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