Polymerization emulsion, preparation method thereof, aqueous adhesive, and preparation method and application of aqueous adhesive

Abstract

The invention discloses a polymerization emulsion, a preparation method thereof, an aqueous adhesive, and a preparation method and an application of the aqueous adhesive. The preparation method of thepolymerization emulsion comprises the following steps: adding water, a chain transfer agent and a sulfonic acid type reactive emulsifier, performing mixing, dropwise adding an acrylic monomer, performing pre-emulsifying, introducing an inert gas to remove O2, adding a cross-linking agent and an initiator, and performing RAFT polymerization to obtain the polymerization emulsion. The aqueous adhesive is prepared through compounding a water-soluble polymer compound, the polymerization emulsion and water, or is prepared through the RAFT polymerization of the water-soluble polymer compound, raw materials for preparing the polymerization emulsion and water. The invention also discloses the preparation method of the aqueous adhesive. The aqueous adhesive is applied to the production of a lithium-sulfur battery positive plate. The polymerization emulsion has the advantages of wide range of suitable monomers, easiness in control and uniform particle size distribution; the aqueous adhesive hasthe advantages of low solid content and wide viscosity range, and a positive electrode made by using the aqueous adhesive has excellent electrochemical performances; and the preparation methods have the advantages of simplicity, low cost, greenness and environmental protection.

Description

technical field [0001] The invention relates to a polymer emulsion, a preparation method, a prepared water-based adhesive, a method and an application, in particular to a polymer emulsion for a lithium-sulfur battery, a preparation method, a prepared water-based adhesive, a method and an application. Background technique [0002] Polymeric emulsions are usually composed of water, monomers, emulsifiers, and initiators. Among them, emulsifiers do not participate in chemical reactions and are not easy to remove. They are mainly brought into the product in the form of physical adsorption on the surface of the polymer, which will affect the applicability of the emulsion. At the same time, it is easy to produce gel under high shear force. Such a polymeric emulsion is used as a binder for the production of lithium secondary battery electrode sheets. During the film formation process of the electrode film, the emulsifier molecules will migrate, forming a layer of emulsifier film on ...

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Problems solved by technology

The fluorine-containing olefin polymer binder represented by PVDF has the disadvantages of ionic and electronic insulation, volume expansion at high temperature, and its dispersant N-methylpyrrolidone (NMP) is unfriendly to the environment, expensive and dissolves polysulfides. , will affect the electrochemical performance of lithium-sulfur batteries, while increasing the cost of battery manufacturing

The main structure of the LA series adhesive is a highly polar polyacrylic acid soap-free copolymerized water emulsion with a high glass transition temperature. During the drying process of the electrode sheet, the flexibility of the electrode sheet decreases with the volatilization of water. Tend to curl, crack or break

CN103367754A discloses a soft-packed water-based lithium iron phosphate power battery and a preparation method thereof. It is a water-based adhesive prepared from a compounding scheme of sodium carboxymethylcellulose (CMC) and styrene-butadiene rubber (SBR). However, its existing The technical defect is that CMC needs to be fully dissolved first, and then mixed and dispersed with electrode materials and SBR, and CMC dissolves slowly in water, easily produces transparent particles, and has poor dispersion, which affects the consistency of the electrode; at the same time, the adhesive of the system is resistant to Poor oxidation ability, generally only suitable for negative electrodes

However, this technical solution needs to prepare bottom liquid, the process is complex, and the binder is usually used for negative electrodes due to its low oxidation resistance, and there are technical obstacles when it is used for lithium-sulfur battery positive electrodes

CN104538634A discloses an electrode binder and a preparation method thereof. The electrode binder has technical obstacles when it is directly used for the positive electrode of a lithium-sulfur battery. At the same time, there are many types of raw materials used, the preparation process is complicated, and the water-based binder is added. the cost of

CN104882612A discloses a binder for lithium-ion batteries, but there are technical obstacles in the direct use of the binder in lithium-sulfur batteries

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