Solid-State Battery Binder Composition for Adhesion and Low IV Resistance
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Solution Overview
Problem
Existing binder compositions for all-solid-state secondary batteries face challenges in achieving a balance between high adhesiveness of the functional layer and low internal resistance (IV resistance) of the battery.
Innovation Solution
A binder composition containing a polymer X with a specific monomer unit A, such as p-styrene sulfonic acid, and an organic solvent with a carbon number of 6 or more, which enhances adhesiveness while minimizing IV resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the amount of binder is increased to improve functional layer adhesiveness, then adhesiveness is improved, but IV resistance increases
Solution Approach 1:
The invention changes the chemical composition parameters of the binder by incorporating specific polymer types with functional groups (carboxyl, hydroxyl, amino) and controlling the binder content within the range of 1-10 parts by mass per 100 parts by mass of solid electrolyte particles. This optimized parameter selection achieves sufficient adhesiveness while minimizing IV resistance increase.
Solution Approach 2:
The invention uses composite binder materials consisting of multiple polymer types with different functional groups (carboxyl-containing polymer, hydroxyl-containing polymer, amino-containing polymer). This composite approach allows the binder to achieve both strong adhesive properties and acceptable electrical conductivity by combining the benefits of different polymer chemistries.
2Ease of manufacture
If conventional binder compositions are used, then manufacturing is simplified, but adhesiveness and IV resistance balance is insufficient
Solution Approach 1:
The invention modifies the chemical parameters of conventional binder compositions by specifying functional group types (carboxyl, hydroxyl, amino) and their quantitative ratios, as well as controlling binder content within 1-10 parts by mass per 100 parts by mass of solid electrolyte particles. These parameter changes maintain manufacturing simplicity while significantly improving the adhesiveness-IV resistance balance.
Data Source
AI summary
Provided is a binder composition that is capable of producing a functional layer having excellent adhesiveness and an all-solid-state secondary battery having low IV resistance. The binder composition contains a binder and an organic solvent having a carbon number of 6 or more. The binder includes a polymer X. The polymer X includes a monomer unit A that includes an aromatic hydrocarbon ring and a functional group bonded directly or indirectly to the aromatic hydrocarbon ring, wherein the functional group is a sulfo group, a carboxy group, and/or an amino group. The proportional content of the monomer unit A in the polymer X is not less than 0.5 mass % and not more than 3.0 mass %.