Trimethoxysilane-terminated polymer adhesive as well as preparation method and application thereof

Abstract

The invention relates to a trimethoxysilane-terminated polymer adhesive, a preparation method and application thereof. The preparation method comprises the following steps: firstly mixing polyurethanesolution and a silane coupling agent, and reacting for 5-8 hours at the temperature of 60-80 DEG C, thus obtaining the trimethoxysilane-terminated polymer adhesive after the reaction is ended; or firstly mixing polyimide solution and the silane coupling agent, and reacting for 5-8 hours, thus obtaining the trimethoxysilane-terminated polymer adhesive. The trimethoxysilane-terminated polymer adhesive, the preparation method and the application have the beneficial effects that a series of adhesives are prepared by crosslinking reaction of the silane coupling agent and polymer, and organic components and inorganic components are combined together to obtain a novel organic-inorganic hybrid polymer adhesive; by combination of the advantages of the mechanical properties of the organic matters and the inorganic matters, the mechanical property is excellent, and stress generated by volume expansion of active materials such as silicon can be effectively borne; when the trimethoxysilane-terminated polymer adhesive is applied in secondary batteries, bonding force between the active material and the adhesive is improved, the integrity of an electrode structure can be effectively maintained, and the cycling stability and the rate performance of an electrode are improved.

Description

technical field [0001] The invention belongs to the field of battery materials, and in particular relates to a silicone-terminated polymer binder and a preparation method and application thereof. Background technique [0002] With the rapid development of information technology, secondary batteries, especially lithium-ion batteries, have basically occupied the market of portable electronic products such as smartphones, notebook computers, and tablets, and are expected to become the power source of growing electric vehicles and hybrid vehicles. important commercial value. At the same time, the newly emerging secondary battery systems - sodium-ion batteries and potassium-ion batteries have great potential due to their abundant resources and low cost. Nevertheless, there are still many problems and defects in the existing secondary battery system. In order to realize its application in new high-power systems such as electric vehicles and energy storage equipment, it is necessa...

AI Technical Summary

Problems solved by technology

The application of PVDF in active materials with small volume changes can effectively adhere the active materials to the current collector, but when used as a binder for active materials with large volume changes, it is prone to plastic deformation, thereby causing the active materials to fall off

In addition, PVDF also has the following disadvantages: 1. The insulating properties of PVDF to ions and electrons will increase the internal resistance of the secondary battery and also affect the performance of the battery

2. There is a certain swelling in the electrolyte, and it will interact with metal lithium and Li X C 6 An exothermic reaction occurs at a higher temperature, and the safety performance is poor

3. After PVDF absorbs water, the molecular weight decreases and the viscosity becomes worse, so the requirements for the humidity of the environment are relatively high

4. The Young's modulus of PVDF is relatively high, between 1 and 4GPa, the flexibility of the pole piece is not good enough

5. PVDF can only be combined with active materials by van der Waals force, and the adhesion is weak

7. At the same time, the price of the binder PVDF is relatively high. The pole piece coating process using PVDF as the binder requires strict sealing, which leads to high energy consumption, high recycling costs, and high production costs.

Currently commonly used binders such as sodium carboxymethyl cellulose, polyacrylic acid, etc., but these binders have a linear chain structure, limited adhesion and mechanical strength, and cannot withstand the mechanical stress caused by the huge volume change of the active material. leading to a rapid reduction in capacity

Chinese patent (publication number: CN105261759A) discloses an adhesive for lithium-ion batteries, specifically polyvinyl alcohol is used as an emulsifier, and styrene and acrylate monomers are polymerized to form an adhesive under the action of an initiator. However, the viscosity of the adhesive is low, and polystyrene has poor mechanical properties, high brittleness, low strength, and is prone to cracking

In addition, the binder contains more emulsifiers, which is detrimental to battery performance to a certain extent

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