Polymer Microsphere Binders for Sulfide Electrolyte Adhesion
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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 ionically conductive sulfidic particles and a polymer binder with specific polymer combinations, where one polymer is insoluble in a non-polar solvent and the other is soluble, allowing for improved mechanical properties and retention of high ionic conductivity, enabling the formation of dense, 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 processability worsens
Solution Approach 1:
The patent uses composite materials by combining inorganic sulfide glass particles with organic polymer binders (such as PVDF, NBR, or SBR) to create a hybrid electrolyte system. The inorganic component provides high ionic conductivity while the organic polymer component provides mechanical flexibility and adhesion to electrodes, thus resolving the contradiction between ionic conductivity and mechanical processability
Solution Approach 2:
The patent changes the physical and chemical parameters of the electrolyte system by controlling particle size distribution, polymer binder content (5-30 wt%), and processing conditions (sintering temperature, pressure) to optimize both ionic conductivity and mechanical adhesion properties simultaneously
2Reliability
If inorganic solid-state electrolytes are used to achieve high ionic conductivity, then ionic conductivity is improved, but mechanical processability into thin films deteriorates
Solution Approach 1:
The composite structure combines brittle inorganic sulfide glass particles with flexible organic polymers, where the polymer matrix provides mechanical compliance that enables processing into thin films while the inorganic particles maintain high ionic conductivity pathways
Solution Approach 2:
The organic polymer binder acts as an intermediary material that facilitates the processing of inorganic particles into thin, dense films by providing a flexible matrix that can be shaped and bonded, while still allowing ionic transport through the inorganic particle network
3Strength
If polymer binders are added to improve adhesion, then adhesion is improved, but ionic conductivity deteriorates
Solution Approach 1:
The patent optimizes the concentration parameter of polymer binder to a specific range (5-30 wt%) and controls the particle size and distribution of inorganic fillers to ensure that ionic conductivity pathways are maintained while sufficient polymer is present to provide adhesion
Solution Approach 2:
The patent creates local quality differentiation where polymer binder is concentrated at the interfaces between electrolyte and electrodes to provide adhesion, while the bulk electrolyte maintains high inorganic particle content to ensure ionic conductivity
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 composite electrolytes exhibit high room temperature conductivities and mechanical strength, addressing the challenges of adhesion and processing, while preventing dendrite formation, thus enabling the use of flexible electronics and improving battery performance.
Implementation Method 1
a polymer binder including a first polymer and a second polymer... the first polymer has a melting temperature (Tm) or a glass transition temperature (Tg) greater than a Tm or Tg of the second polymer
Implementation Method 2
ionically conductive sulfidic particles... exhibit high room temperature conductivities
Data Source
AI summary
Provided herein are composite electrolytes that include inorganic conductors and polar polymers. By providing the polar polymers as structures such as microspheres in a suspension in a non-polar solvent, the polar polymers can be used as binders in composites that include sulfide electrolytes. The resulting composites have high room temperature conductivities and good mechanical properties. Also provided are composites that include inorganic conductors and other polymers that are insoluble in non-polar solvents. Also provides methods of forming composite electrolytes using suspensions of polymer microstructures in a processing solvent and the resulting composite electrolytes.