Composite Electrolyte Binders for Conductive Thin Sulfide Films
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Solution Overview
Problem
The commercialization of solid-state electrolytes for batteries is hindered by challenges such as maintaining contact between the electrolyte and electrodes, the brittleness of glass and ceramic conductors, and the reduction in ionic conductivity due to the addition of solid polymer binders.
Innovation Solution
A composite is developed comprising ionically conductive sulfidic particles and a polymer binder made of a first and second polymer, where the first polymer is insoluble in a non-polar solvent and has a higher melting temperature or glass transition temperature than the second polymer, which is soluble in the non-polar solvent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inorganic solid-state electrolytes are used to achieve high ionic conductivity, then ionic conductivity is improved, but adhesion to electrodes deteriorates
Solution Approach 1:
The patent uses a composite binder system consisting of a first polymer (insoluble in non-polar solvent, higher Tm/Tg) and a second polymer (soluble in non-polar solvent, lower Tm/Tg) to achieve both strong adhesion and high ionic conductivity. The first polymer provides structural integrity and adhesion, while the second polymer ensures processability and maintains ionic conductivity pathways.
Solution Approach 2:
The patent carefully controls the weight percentages of the two polymers (first polymer: 5-50 wt%, second polymer: 5-45 wt%) to optimize the balance between adhesion strength and ionic conductivity. The specific temperature parameters (Tm, Tg) are selected to ensure the binder remains stable during battery operation while allowing processing at lower temperatures.
2Reliability
If glass and ceramic solid-state conductors are processed into thin films to reduce bulk resistance, then ionic conductivity is improved, but mechanical brittleness worsens processing difficulty
Solution Approach 1:
The patent introduces a polymer binder as an intermediary material that facilitates the processing of brittle inorganic electrolyte particles into flexible thin films. The binder acts as a matrix that holds the inorganic particles together, enabling film formation without requiring the inorganic material itself to be ductile.
Solution Approach 2:
The patent creates a flexible composite thin film structure where the polymer binder provides the flexible matrix that allows the brittle inorganic electrolyte particles to be processed into thin, flexible films suitable for large-scale manufacturing.
3Strength
If solid polymer binder is added to improve adhesion, then adhesion is improved, but ionic conductivity decreases
Solution Approach 1:
The patent creates a heterogeneous binder system where the first polymer (insoluble, higher Tm/Tg) provides localized adhesion zones, while the second polymer (soluble, lower Tm/Tg) creates continuous ionic conductivity pathways. This local differentiation of functions allows simultaneous achievement of adhesion and conductivity.
Solution Approach 2:
The patent uses a composite binder system where the two polymers work synergistically: the first polymer provides structural support and adhesion, while the second polymer ensures processability and maintains ionic conductivity, achieving both adhesion and conductivity that neither polymer could achieve alone.
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 achieves high room temperature ionic conductivities and improved mechanical properties, enabling efficient processing into thin films and maintaining contact with electrodes, thus addressing the challenges of large-scale commercialization.
Implementation Method 1
the first polymer is insoluble in a non-polar solvent
Implementation Method 2
the second polymer is soluble in the non-polar solvent
Implementation Method 3
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 4
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 5
ionically conductive sulfidic particles
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 provided are composites that include polar polymers and lithium argyrodite conductors and methods of processing the composites that result in high conductivity retention. Also provided are methods of forming composite electrolytes using suspensions of polymer microstructures in a processing solvent and the resulting composite electrolytes.