Dopamine-modified polyimide battery diaphragm as well as preparation method and application thereof

Abstract

The invention belongs to the field of battery diaphragms, and discloses a dopamine-modified polyimide battery diaphragm as well as a preparation method and application thereof. The preparation methodcomprises the following steps: S1, soaking a carrier in a dopamine solution, and conducting oscillating at room temperature until the carrier is uniformly mixed to obtain a dopamine-loaded carrier; S2, adding the dopamine-loaded carrier and an additive into a precursor polyamide acid (PAA) solution, and carrying out stirring to obtain a mixed solution, wherein the additive is one or more selectedfrom the group consisting of poly(ethylene oxide), poly(propylene oxide), polyethylene glycol, dimethyl phthalate, polymethyl methacrylate and polyurethane; and S3, coating polytetrafluoroethylene with the mixed solution, and carrying out chemical imidization or thermal imidization treatment to obtain a polyimide porous film, wherein the thermal imidization is carried out in a programmed stepped heating curing manner consisting of three sections, namely 100 DEG C / 1h, 200 DEG C / 1h and 300 DEG C / 1h. Through the mutual synergistic effect of dopamine, the carrier and the additive, the liquid absorption capacity of the battery diaphragm is improved, and the porosity and other related properties of the battery diaphragm are improved.

Description

technical field [0001] The invention relates to the technical field of battery diaphragms, and more particularly, to a preparation method and application of a dopamine-modified polyimide battery diaphragm. Background technique [0002] Lithium-ion secondary battery is a kind of reusable battery and also a kind of clean energy, which has attracted more and more researchers' attention. Lithium batteries are composed of five main components: positive electrode, negative electrode, electrolyte, battery separator and battery case. Lithium-ion battery separator is a layer of functional film placed between the positive and negative electrodes of the battery. Its main function is to prevent short-circuiting of the positive and negative electrodes, and it can also transport ions and charge carriers in the closed channel of the lithium-ion battery. Commercial separators have problems such as low porosity, poor wettability, and high temperature resistance, which affect the charge-disc...

AI Technical Summary

Problems solved by technology

[0003] Chinese patent (CN103545474A) discloses a polydopamine-modified lithium-ion battery diaphragm and a preparation method thereof, wherein the method discloses a polydopamine-modified polyimide lithium-ion battery diaphragm, and the scheme includes a polydopamine coating It is composed of two parts with the polymer porous membrane matrix. It uses the high temperature resistance of polyimide and the strong bonding force of dopamine to improve the high temperature resistance and the ability to absorb / retain the electrolyte, but it cannot improve the porosity of the battery separator. Rate

Images