Li-Ion Conductive Binder Solution for Stable Solid-State Electrodes
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Solution Overview
Problem
Conventional all-solid-state batteries face limitations in stability, energy density, and high-temperature performance due to the use of organic solvents and low lithium ion conductivity of polymer binders, which restricts the capacity and lifetime of the batteries.
Innovation Solution
A binder solution comprising a first binder with low lithium ion conductivity, a second binder with higher lithium ion conductivity, a lithium salt, and an organic solvent is used to enhance binding force and lithium ion transport in electrodes, allowing for improved charge-discharge capacity and stability, especially in high-temperature environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a non-polar polymer binder is used to suppress chemical reaction with sulfide solid electrolyte, then chemical stability is improved, but lithium ion conductivity deteriorates
Solution Approach 1:
The patent uses a composite binder system combining a non-polar polymer binder (for chemical stability) with a polar polymer binder containing lithium ion conductive groups (for lithium ion conductivity). This composite approach allows both functions to coexist: the non-polar binder suppresses chemical reactions with the sulfide solid electrolyte while the polar binder provides the necessary lithium ion transport pathways, resolving the contradiction between chemical stability and ionic conductivity.
2Ease of manufacture
If organic solvents are used in conventional secondary batteries, then ease of manufacture is improved, but stability and energy density deteriorate
Solution Approach 1:
The patent changes the fundamental parameter of the electrolyte phase from organic liquid to inorganic solid (sulfide solid electrolyte). This parameter change eliminates the stability and energy density limitations associated with organic solvents while maintaining manufacturability through wet process techniques. The solid electrolyte provides inherent stability and enables higher energy density configurations.
Solution Approach 2:
The patent replaces the liquid electrolyte system (organic solvent-based) with a solid electrolyte system (inorganic solid). This substitution eliminates the safety and stability issues associated with organic solvents while maintaining the ability to form electrode structures through wet processing methods, thus resolving the contradiction between ease of manufacture and stability.
3Reliability
If a binder with low lithium ion conductivity is used, then chemical stability is improved, but charge-discharge capacity and lifetime deteriorate
Solution Approach 1:
The patent employs a composite binder comprising a non-polar polymer binder (providing chemical stability) and a polar polymer binder with lithium ion conductive groups (providing high lithium ion conductivity). This composite structure ensures both chemical stability and high charge-discharge capacity, as the polar binder creates efficient lithium ion transport pathways while the non-polar binder maintains chemical inertness toward the solid electrolyte, thereby extending battery lifetime.
4Ease of operation
If conventional polymer binder is used, then ease of operation is improved, but lithium ion conductivity and output characteristics deteriorate
Solution Approach 1:
The patent modifies the binder by introducing lithium ion conductive groups into the polymer structure, changing its electrical parameters. The polar polymer binder contains functional groups that facilitate lithium ion transport, significantly enhancing ionic conductivity while maintaining the ease of handling and processing characteristics of conventional polymer binders. This parameter change enables high output characteristics without sacrificing operational ease.
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 binder solution effectively forms a lithium ion transport path, enhancing the charge-discharge capacity and prolonging the lifetime of all-solid-state batteries, while maintaining stability and enabling large-area manufacturing and high-temperature operation.
Implementation Method 1
an organic solvent that dissolves the lithium salt
Implementation Method 2
a lithium ion transport path is formed when the particles contact each other
Data Source
AI summary
The present disclosure relates to a binder solution having lithium ion conductivity for an all-solid-state battery and an electrode slurry including the same. Specifically, the binder solution includes a first binder having high binding force, a second binder having higher lithium ion conductivity than that of the first binder, a lithium salt, and an organic solvent that dissolves the lithium salt.