Formation method of nano coating of lithium ion battery membrane

Abstract

The invention discloses a formation method of a nano coating of a lithium ion battery membrane. The formation method comprises the following steps: (1) dissolving an aqueous adhesive and an additive into de-ionized water and stirring for 3h to obtain an aqueous adhesive mixed solution; (2) adding an inorganic material nano-sol into the aqueous adhesive mixed solution; continually stirring for 2h and standing for 1h to obtain aqueous nano coating paint; (3) putting a polyethylene membrane into a plasma treatment device for treating, so as to primarily improve the surface of the membrane; then coating the surface of the lithium ion battery membrane and the surface of a three-dimensional pore channel with the aqueous nano coating paint; drying the coated membrane in the air for 10min and then transferring the membrane into a drying box at 40 DEG C; drying to obtain the lithium ion battery membrane modified by a nano inorganic coating. The battery membrane disclosed by the invention can be used for modifying the surface of the membrane and the pore channel under the condition that the thickness of the membrane is not increased; the speed of ions penetrating through the membrane is improved, and the ion conductivity and the lithium-ion transference number of the membrane are improved; when the modified membrane is used for assembling a battery, the circulating performance of the battery is remarkably improved.

Description

technical field [0001] The invention relates to a method for forming a lithium-ion battery diaphragm nano-coating, which belongs to the technical field of lithium batteries. Background technique [0002] The green high-energy lithium-ion battery has attracted more and more attention because of its high operating voltage, long cycle life, and low self-discharge effect. Lithium-ion batteries are mainly composed of four parts: positive electrode, negative electrode, separator and electrolyte. The separator acts as a porous film between the positive and negative electrodes, which blocks the passage of electrons in the battery but allows lithium ions to pass through. Most importantly, the internal resistance and interface structure of the battery are closely related to the performance of the separator, which can directly affect the cycle, rate performance and safety performance of the battery. [0003] At present, polyolefin diaphragm is the leading material of lithium-ion batt...

AI Technical Summary

Problems solved by technology

[0003] At present, polyolefin diaphragm is the leading material of lithium-ion battery diaphragm. The advantages of this type of diaphragm are: low price, excellent mechanical properties and relatively stable chemical properties, but there are also defects: poor wettability and poor lyophilicity to electrolyte , low liquid holdup, etc., and this also directly affects the electrical conductivity of the separator, and the electrochemical performance of the lithium ion migration number.

At present, the thickness of the traditional ceramic coating is often relatively thick. Due to the large particle size in the coating liquid, the coating is not easy to penetrate into the pores of the diaphragm. Although it can improve the thermal stability of the diaphragm, the particle size in the coating liquid is relatively small. Large lead to serious plugging of the lithium-ion separator, thereby reducing the conductivity of the battery and the number of lithium-ion migration

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