Block Polymer Binder for All-Solid State Battery Interfacial Resistance
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Solution Overview
Problem
All-solid state secondary batteries face challenges in achieving sufficient interfacial contact between solid particles, leading to increased electric resistance due to insufficient dispersion stability of solid particles, which existing binders are unable to fully address, especially in the context of advanced applications like electric vehicles.
Innovation Solution
An inorganic solid electrolyte-containing composition is developed, utilizing a block polymer with a terminal block chain having a C Log P value of 2 or more and a block chain with a C Log P value of 1 or less, forming binder particles with specific sizes and functional groups to enhance dispersion stability and reduce interfacial resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing binders are used to form constitutional layers in all-solid state secondary batteries, then the battery structure can be assembled, but the interfacial contact state between solid particles is insufficient leading to increased interfacial resistance and electric resistance
Solution Approach 1:
The invention changes the chemical composition parameters of the binder by specifying precise proportions of different functional groups (carboxyl group 0.01-5 mmol/g, hydroxyl group 0.01-5 mmol/g, ether group 0.1-10 mmol/g). These parameter changes enable the binder to achieve optimal interfacial contact with solid particles while maintaining low interfacial resistance, resolving the contradiction between structural assembly and electrical performance.
Solution Approach 2:
The invention creates a composite binder material combining multiple functional groups (carboxyl, hydroxyl, and ether groups) in specific ratios. This composite structure allows the binder to simultaneously provide adhesion, coordination bonding, and flexible interfacial contact, thereby improving interfacial contact state while reducing interfacial resistance between solid particles.
2Stability of the object's composition
If solid particle materials are used to form constitutional layers, then the all-solid state battery structure is achieved, but the dispersion stability of solid particles is insufficient leading to increased electric resistance
Solution Approach 1:
The binder acts as an intermediary substance between solid particles, with specific functional groups that coordinate with particle surfaces. The carboxyl and hydroxyl groups provide strong binding to particle surfaces while the ether groups extend into the bulk, creating a stable dispersion network that prevents particle aggregation and maintains low electrical resistance pathways.
Solution Approach 2:
By precisely controlling the functional group concentrations in the binder (carboxyl: 0.01-5 mmol/g, hydroxyl: 0.01-5 mmol/g, ether: 0.1-10 mmol/g), the invention optimizes the interaction parameters between binder and solid particles. This parameter optimization ensures sufficient dispersion stability while maintaining continuous conductive pathways, thereby reducing electric resistance.
3Strength
If a binder with high binding strength is used to improve interfacial contact, then the binding state between solid particles improves, but the complexity of binder composition increases
Solution Approach 1:
The invention simplifies the binder composition by defining specific parameter ranges for functional groups rather than using complex polymer structures. The carboxyl, hydroxyl, and ether groups can be incorporated into relatively simple polymer backbones, achieving strong binding through controlled chemical composition parameters rather than through complex molecular architectures.
Data Source
AI summary
There is provided an inorganic solid electrolyte-containing composition containing an inorganic solid electrolyte, binder particles having an average particle diameter of 10 to 1,000 nm, and a dispersion medium, in which a block polymer is contained to constitute the binder particles, this block polymer contains a block polymerized chain which has a terminal block chain having a C Log P value of 2 or more and having a specific constitutional component and has a block chain having a C Log P value of 1 or less, the block chain being adjacent to this terminal block chain. There are also provided a sheet for an all-solid state secondary battery and an all-solid state secondary battery, and manufacturing methods for a sheet for an all-solid state secondary battery and an all-solid state secondary battery.