Ketone Solvent Slurry for All-Solid-State Battery Binding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The use of PVDF binder in all-solid-state batteries results in low binding force due to low solubility in non-polar solvents and significant deterioration of sulfide solid electrolytes when polar solvents are used, making it difficult to achieve sufficient binding force while minimizing binder content and preventing electrolyte degradation.
Innovation Solution
A method involving a slurry with a ketone solvent, containing at least 50% of a ketone solvent represented by a general formula with saturated or aromatic hydrocarbon groups, which enhances PVDF binder solubility and reduces electrolyte deterioration, allowing for lower binder content and improved binding force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a non-polar solvent is used to dissolve PVDF binder, then the PVDF binder remains in a dispersed state with low binding force, but using a polar solvent significantly deteriorates the sulfide solid electrolyte
Solution Approach 1:
The patent changes the chemical parameter of the solvent from traditional non-polar or polar solvents to a specific ketone solvent with defined molecular structure (formula 1) and polarity characteristics. This parameter change enables the PVDF binder to achieve adequate dissolution and binding force while preventing sulfide solid electrolyte deterioration, resolving the contradiction between binding force and electrolyte stability.
Solution Approach 2:
The ketone solvent acts as an intermediary substance that mediates between the PVDF binder and sulfide solid electrolyte. It provides the necessary solubility for PVDF to achieve sufficient binding force while simultaneously maintaining chemical compatibility with the sulfide solid electrolyte, preventing deterioration. The solvent formula (1) with specific hydrocarbon groups serves as this intermediary medium.
2Strength
If the used amount of PVDF binder is increased to obtain sufficient binding force, then the binding force improves, but the binder content increases and may affect battery performance
Solution Approach 1:
By changing the solvent parameter to a specific ketone solvent with optimized polarity and molecular structure, the patent improves the dissolution efficiency of PVDF binder. This enables achieving sufficient binding force with a reduced binder content, as the ketone solvent enhances the binding effectiveness per unit amount of binder used.
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 method achieves a sufficient binding force with reduced PVDF binder content and suppresses sulfide solid electrolyte deterioration, resulting in a high-performance all-solid-state battery with improved cycle properties and voltage resistance.
Implementation Method 1
The solubility to a non-polar solvent (such as heptane) of the PVDF binder is extremely low. Therefore, when a non-polar solvent is used to the PVDF binder, the PVDF binder will be in a dispersed state (agglomerated stat) so that the binding force per used amount will be low.
Data Source
AI summary
A main object of the present disclosure is to provide a method for producing an all-solid-state battery in which the used amount of the PVDF binder may be decreased, and the deterioration of the sulfide solid electrolyte may be suppressed. The present disclosure achieves the object by providing a method for producing an all-solid-state battery, the method comprising a step of forming an electrolyte-containing layer by using a slurry including a sulfide solid electrolyte containing a Li element, a P element, and a S element, a PVDF binder, and a solvent, and as a first solvent, the solvent includes 50 volume % or more of a ketone solvent represented by a general formula (1):wherein, in the general formula (1), R1 and R2 are each independently a saturated hydrocarbon group or an aromatic hydrocarbon group, and a carbon number of at least one of R1 and R2 is 2 or more.