Composite Electrolyte Binders for Thin Solid-State Battery Films
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Solution Overview
Problem
Solid-state electrolytes face challenges in large-scale commercialization due to poor adhesion to electrodes and mechanical properties, leading to high bulk resistance and dendrite formation, particularly with inorganic materials like sulfide glasses and ceramics, which are brittle and difficult to process into dense, thin films without sacrificing ionic conductivity.
Innovation Solution
A composite electrolyte system incorporating inorganic ionically conductive particles with an organic phase containing a polymer binder modified with functional groups, such as SEBS or PVDF, which provides improved mechanical properties and maintains high ionic conductivity, enabling the formation of flexible and bendable thin films suitable for all-solid-state batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inorganic solid-state electrolytes (sulfide glasses and ceramics) are used to achieve high ionic conductivity, then ionic conductivity is improved, but adhesion to electrodes deteriorates and mechanical properties worsen
Solution Approach 1:
The patent uses composite materials by combining inorganic ionically conductive particles with an organic polymer binder to create a hybrid electrolyte system. This composite structure allows the inorganic phase to provide high ionic conductivity while the organic polymer phase provides mechanical flexibility and adhesion to electrodes, resolving the contradiction between conductivity and mechanical strength
Solution Approach 2:
The patent modifies the polymer binder by introducing functional groups (such as carboxylic acid groups) to change its chemical properties. This parameter change enables the polymer to form strong chemical bonds with inorganic particles and electrodes, significantly improving adhesion while maintaining the ionic conductivity provided by the inorganic phase
2Length of stationary object
If glass and ceramic solid-state conductors are processed into thin films to reduce bulk resistance, then film thickness is reduced, but mechanical brittleness worsens and processing difficulty increases
Solution Approach 1:
The patent changes the mechanical parameters of the electrolyte system by incorporating a flexible polymer binder with the inorganic particles. This parameter change transforms the brittle nature of pure glass/ceramic into a processable composite material that can be formed into thin films through techniques like slurry casting, while maintaining low bulk resistance due to the thin film geometry
3Strength
If polymer binder is added to improve adhesion and mechanical properties, then adhesion is improved, but ionic conductivity decreases
Solution Approach 1:
The patent applies local quality by using a small, optimized amount of polymer binder (5-20 wt%) rather than a continuous polymer matrix. The polymer is strategically positioned to provide adhesion at interfaces (electrode-electrolyte contact) while minimizing its presence in the bulk to preserve ionic conductivity pathways through the inorganic particle network
Solution Approach 2:
The composite structure allows the inorganic particles to form the primary ionic conduction network while the polymer binder serves as a secondary phase for mechanical support and adhesion. This division of function enables both high adhesion and maintained ionic conductivity
Data Source
AI summary
Functionalized polymeric binders for electrolyte and electrode compositions include a polymer having a polymer backbone and functional groups. In some embodiments, a polymer includes a non-polar polymer backbone and a functional group that is 0.1 to 5 wt % of the polymer. In some embodiments, a polymer includes a polar backbone and a functional group that is 0.1 to 50% weight percent of the polymer. Also described are composites for electrolyte separators and electrodes that include argyrodite ion conductors and polar polymers.