Solid-State Battery Binder Composition for Slurry Dispersion and Cycle Life
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Solution Overview
Problem
Conventional binder compositions for all-solid-state secondary batteries lack sufficient dispersibility and cycle characteristics, which are essential for improving the performance and safety of these batteries.
Innovation Solution
A binder composition comprising a polymer with a nitrile group-containing monomer unit and a (meth)acrylic acid ester monomer unit, combined with an aromatic halide and specific metals, enhances the dispersibility and cycle characteristics of the slurry composition and solid electrolyte-containing layer in all-solid-state secondary batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional binder compositions are used, then the battery can be manufactured, but the dispersibility of slurry composition is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the binder by incorporating specific polymers (polyacrylic acid, polyacrylamide, polyvinyl alcohol, carboxymethyl cellulose, or starch) in controlled amounts (0.1-10 wt% relative to solid electrolyte). This parameter adjustment optimizes both dispersibility and cycle characteristics simultaneously
Solution Approach 2:
The patent creates a composite binder system by combining multiple components: solid electrolyte particles, binder material, and specific polymer additives. This composite approach allows the different materials to work synergistically, where the polymers enhance dispersibility while the binder matrix maintains structural integrity for good cycle characteristics
2Reliability
If conventional binder compositions are used, then the battery structure can be formed, but the cycle characteristics are insufficient
Solution Approach 1:
The patent adjusts the molecular weight and chemical structure parameters of the binder components. Specifically, it uses polymers with controlled molecular weights and functional groups (carboxyl, amide, hydroxyl) that enhance both the stability of the slurry composition and the durability during cycling
Solution Approach 2:
The patent introduces polymer molecules as intermediary substances between the solid electrolyte particles and the binder matrix. These polymers act as mediators that improve interfacial compatibility, enhance dispersibility during slurry formation, and maintain stable electrical contact during cycling
Data Source
AI summary
Provided is a binder composition with which it is possible to produce a slurry composition having excellent dispersibility and to form a solid electrolyte-containing layer that can cause an all-solid-state secondary battery to display excellent cycle characteristics. The binder composition contains a polymer and an aromatic halide. The polymer includes a nitrile group-containing monomer unit in a proportion of 10 mass % to 35 mass % and a (meth)acrylic acid ester monomer unit in a proportion of 15 mass % to 40 mass %. The aromatic halide has a structure in which not less than 2 and not more than 4 halogen atoms are bonded directly to an aromatic ring, and the content of the aromatic halide in the binder composition is 5 mass ppm to 3,000 mass ppm relative to the content of the polymer.