Solid Electrolyte Sheet Composition for Low-Resistance Battery Interfaces
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Solution Overview
Problem
Existing all-solid state secondary batteries face challenges with interface resistance and adhesive force between solid particles, leading to increased battery resistance and deterioration in cycle characteristics.
Innovation Solution
An inorganic solid electrolyte-containing composition is developed, comprising an inorganic solid electrolyte, a polymer binder, a compound with specific functional groups, and a dispersion medium, which improves dispersion stability and handleability, and reduces interface resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If solid particles are used to form constitutional layers, then the battery structure is simplified and energy density is increased, but interface resistance increases and adhesive force between particles deteriorates
Solution Approach 1:
The patent introduces a binder as an intermediary substance between solid particles (inorganic solid electrolyte, active material, conductive auxiliary agent) to improve interface contact and reduce resistance. The binder mediates the interaction between particles, enabling better adhesion and electrical/ionical conductivity at interfaces without compromising the solid-state structure simplification.
Solution Approach 2:
The patent creates a composite material system combining solid particles with binder material to form constitutional layers. This composite approach allows simultaneous achievement of structural simplification (through solid particles) and reduced interface resistance (through binder-mediated composite structure), where the binder forms a matrix that connects particles and enhances interfacial properties.
2Quantity of substance
If solid particles are used to form constitutional layers, then energy density is increased, but adhesive force between particles deteriorates
Solution Approach 1:
The binder acts as a mediator that enhances adhesive force between solid particles while maintaining high particle content for energy density. The binder material provides bonding functionality that compensates for the inherently weak particle-particle adhesion in solid-state systems, enabling firm adhesion without reducing the quantity of energy-storing solid materials.
Solution Approach 2:
The patent applies local quality by having the binder concentrate at particle interfaces and contact points, providing localized adhesion enhancement where needed most. This allows the bulk material to maintain high solid particle content for energy density, while the binder provides localized bonding at critical interface regions.
3Productivity
If constitutional layer forming material is used, then productivity is improved, but dispersibility and fluidity characteristics become difficult to maintain simultaneously
Solution Approach 1:
The patent optimizes parameters of the binder material (molecular weight, functional groups, composition ratios) to achieve a balance between dispersibility and fluidity. By carefully selecting and adjusting binder parameters, the patent enables the constitutional layer forming material to maintain both good particle dispersibility and appropriate fluidity for coating operations, while still improving productivity through efficient material formulation.
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 enables the formation of a constitutional layer with low resistance and excellent cycle characteristics, enhancing the performance and longevity of all-solid state secondary batteries.
Implementation Method 1
a technique of containing a dispersant of an inorganic solid electrolyte or the like for the purpose of improving the dispersibility of the inorganic solid electrolyte in the constitutional layer forming material
Implementation Method 2
the adhesive force between the solid particles is not sufficient, which causes further deterioration in cycle characteristics
Implementation Method 3
an inorganic solid electrolyte, particularly an oxide-based inorganic solid electrolyte or a sulfide-based inorganic solid electrolyte is expected as an electrolyte material having a high ion conductivity comparable to that of the organic electrolytic solution
Data Source
AI summary
Provided are an inorganic solid electrolyte-containing composition containing an inorganic solid electrolyte, a polymer binder, a compound, and a dispersion medium, in which the inorganic solid electrolyte-containing composition satisfies Conditions (1) to (3); a sheet for an all-solid state secondary battery and an all-solid state secondary battery, which are formed of the inorganic solid electrolyte-containing composition; and manufacturing methods for a sheet for an all-solid state secondary battery and an all-solid state secondary battery.Condition (1): a mass average molecular weight of polymer constituting polymer binder is 2,000 or moreCondition (2): the compound has at least one specific functional groupCondition (3): a molecular weight of the compound is less than 2.0×103, and the compound is dissolved in the dispersion medium.