Positive Electrode Binder Composition for Thick High-Loading Coatings
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current binder compositions for lithium ion secondary battery positive electrodes lack high binding properties and flexibility, which are essential for achieving high energy density and durability.
Innovation Solution
A composition comprising a graft copolymer-based resin and a polyvinylidene fluoride-based resin, where the graft copolymer is formed by graft-copolymerizing (meth)acrylonitrile with polyvinyl alcohol, offering a mass ratio of 2/8 to 8/2, along with optional (meth)acrylonitrile-based non-graft polymer and polyvinyl alcohol homopolymer, to enhance binding and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional binder compositions are used for positive electrodes, then the electrode structure is simple and easy to manufacture, but the binding properties and flexibility are insufficient
Solution Approach 1:
The patent applies composite materials by combining graft copolymer-based resin (with polyvinyl alcohol and (meth)acrylonitrile components) and polyvinylidene fluoride-based resin in a specific mass ratio (2/8 to 8/2). This composite binder composition achieves both high binding properties and flexibility, resolving the contradiction between strength and complexity by creating a synergistic material system where each component contributes specific functional properties.
2Quantity of substance
If the proportion of active material and electrode thickness are increased to achieve high energy density, then the energy density improves, but the adhesive strength and flexibility may deteriorate
Solution Approach 1:
The patent applies parameter changes by optimizing the mass ratio of graft copolymer-based resin to polyvinylidene fluoride-based resin (2/8 to 8/2). By adjusting this compositional parameter, the binder maintains adequate adhesive strength even when active material proportion and electrode thickness are increased, thus enabling high energy density without sacrificing binding properties.
3Reliability
If polyvinylidene fluoride is used as the binder composition, then the oxidation resistance is improved, but the binding properties and flexibility are insufficient
Solution Approach 1:
The patent merges polyvinylidene fluoride-based resin (providing oxidation resistance) with graft copolymer-based resin containing polyvinyl alcohol and (meth)acrylonitrile (providing binding properties and flexibility). This combination allows the electrode to simultaneously achieve oxidation resistance and adequate binding properties, resolving the contradiction between reliability and strength.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composition provides a positive electrode with high binding properties and flexibility, enabling increased active material proportion and electrode thickness while maintaining adhesive strength and flexibility, thus achieving high energy density in lithium ion secondary batteries.
Implementation Method 1
the graft copolymer-based resin includes a graft copolymer in which a monomer, having a (meth)acrylonitle as a main component, is graft-copolymerized with a polyvinyl alcohol
Data Source
AI summary
An object of the present invention is to provide a composition for a positive electrode having high binding properties and high flexibility. A composition for a positive electrode, comprising: a graft copolymer-based resin; a polyvinylidene fluoride-based resin, wherein the graft copolymer-based resin includes a graft copolymer in which a monomer, having (meth)acrylonitrile as a main component, is graft-copolymerized with a polyvinyl alcohol. The graft copolymer-based resin optionally further includes at least one of a (meth)acrylonitrile-based non-graft polymer and a polyvinyl alcohol homopolymer. And, a slurry for a positive electrode comprising the composition. A positive electrode comprising a metal foil and a coating film of the slurry. The composition preferably has a mass ratio of the graft copolymer-based resin and the polyvinylidene fluoride resin, which is: graft copolymer-based resin/polyvinylidene fluoride-based resin=2/8 to 8/2.