Multielement functional modified polymer binder for lithium ion battery and application of binder in electrochemical energy storage device

Abstract

The invention discloses a multielement functional modified binder for a polymer lithium ion battery. The binder takes a biomass polymer or a synthetic polymer as the substrate, takes a hydrophilic monomer and an oleophilic monomer as the functional modified monomer; and then the binder is prepared through a free radical graft copolymerization reaction or a Michael addition reaction in a modification manner. The binder has a multi-branch structured three-dimensional space network body, so that more active sites in contact with the electrode active material can be provided, and the uniformity and the smoothness of the electrode slurry in film-forming can be improved; the peeling strength of the active materials and the conductive agent on the metal substrate is reinforced; and meanwhile, the binder is excellent in elasticity and binding force, can be applied to water / organic solvent and can be applied to the positive electrode and negative electrode of the lithium ion battery; the conduction of electrons / ions in the charging-discharging process can be promoted; the electrochemical interface impedance of the pole piece is lowered; the high rate capacity and the cycling stability of the positive electrode material and the negative electrode material of the lithium battery are relatively improved; in addition, the synthetic raw material is wide in source, so that the cost can be obviously lowered; and therefore, the binder has a wide market prospect.

Description

Technical field: [0001] The invention relates to a polymer lithium ion battery binder, in particular to a multifunctional modified polymer lithium ion battery binder and its application in electrochemical energy storage devices. Background technique: [0002] In the battery manufacturing process, it is necessary to use a binder to bond the powder electrode active material. As an important inactive component of a lithium-ion battery, the binder adheres the electrode active material and the conductive agent to the current collector, and its performance directly affects the electrochemical performance of the battery. In addition to the role of bonding between the electrode active material, the conductive agent and the current collector, the binder should have sufficient elasticity to prevent the active material particles from swelling due to their own expansion and contraction during battery charging and discharging. Shedding, and facilitates the conduction of electrons and ions du...

AI Technical Summary

Problems solved by technology

Styrene-butadiene rubber (SBR) / sodium carboxymethylcellulose (CMC) and polyacrylate water-based binders have been used in large-scale markets, but their adhesion, flatness of the pole piece and the effect of inhibiting the expansion of the pole piece are limited, so its scope of use is subject to certain restrictions

PVA as an emulsifier, copolymerization of styrene monomer and acrylate monomer (CN105261759A) can prepare water-based binder for lithium-ion batteries, but the disadvantages of polystyrene are brittleness, low impact strength, and easy occurrence of stress Cracking, poor heat resistance, etc.

Modified marine polysaccharide polymers (CN105576247A), such as the copolymerization of chitosan with acrylic acid and its ester monomers, can be used to prepare water-based binders for lithium-ion batteries, but their intrinsic bonding strength and elasticity are insufficient. The uniformity and flatness need to be further improved

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