TPV Solid Polymer Electrolytes for Dendrite-Resistant Li-Ion Cells
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Solution Overview
Problem
Existing solid-state batteries face issues with lithium dendrite growth, limited lifetime, and safety concerns due to flammable liquid electrolytes, while existing polymer electrolytes lack sufficient ionic conductivity and mechanical strength, and are not easily reprocessable.
Innovation Solution
Development of thermoplastic vulcanizate (TPV) based solid polymer electrolytes (SPEs) comprising a crosslinked elastomer phase and a thermoplastic polymer phase, with specific ratios and additives to enhance mechanical properties and ionic conductivity, allowing for a cost-effective and efficient industrial production process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If liquid electrolytes are used in Li-ion batteries, then good mobility of Li+ cations is achieved, but flammability and thermal runaway risks increase
Solution Approach 1:
The patent changes the physical state parameter of the electrolyte from liquid to solid gel form, maintaining ionic conductivity while eliminating flammability risks associated with liquid electrolytes
Solution Approach 2:
The patent creates a composite gel electrolyte system combining crosslinked elastomer phase, thermoplastic polymer phase, and lithium salt, integrating the benefits of mechanical strength from polymers and ionic conductivity from lithium salts while eliminating liquid electrolyte hazards
2Object-affected harmful factors
If polymer electrolytes are used to replace liquid electrolytes, then safety is improved, but ionic conductivity and mechanical strength are insufficient
Solution Approach 1:
The patent develops a composite gel electrolyte comprising crosslinked elastomer phase providing mechanical strength and flexibility, thermoplastic polymer phase providing structural integrity, and lithium salt providing ionic conductivity, achieving simultaneous improvement in all three properties
Solution Approach 2:
The patent creates distinct phases with specialized functions: crosslinked elastomer domains provide mechanical strength and dendrite resistance, while thermoplastic polymer regions provide ionic transport pathways, optimizing local properties for specific functions
3Strength
If completely crosslinked polymer electrolyte systems are used, then mechanical strength is improved, but reprocessability is lost
Solution Approach 1:
The patent segments the polymer system into two distinct phases: crosslinked elastomer phase providing mechanical strength and thermoplastic polymer phase maintaining reprocessability, allowing the material to exhibit both desired properties simultaneously
Solution Approach 2:
The patent controls the degree of crosslinking to create a partial crosslinking state where sufficient crosslinks provide mechanical strength but enough uncrosslinked thermoplastic polymer remains to allow reprocessing and reshaping
4Strength
If crystalline or vitreous polymers are used for mechanical reinforcement, then mechanical strength is improved, but ionic conductivity decreases
Solution Approach 1:
The patent combines crystalline/vitreous polymer phases for mechanical reinforcement with amorphous gel phases containing lithium salts for ionic conductivity, creating a composite structure where each phase performs its optimal function
Solution Approach 2:
The patent creates local amorphous regions within the polymer matrix where lithium ions can move freely, while maintaining overall crystalline or vitreous structure for mechanical strength, optimizing both properties through spatial differentiation
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 TPV SPEs exhibit improved electrochemical stability, high mechanical strength, resistance to lithium dendrite growth, and enhanced cyclability, making them suitable for high-performance solid-state batteries.
Implementation Method 1
a crosslinked elastomer phase and a thermoplastic polymer phase
Implementation Method 2
ionic conductive solid electrolytes for solid state batteries notably to promote the safety of the systems
Implementation Method 3
resistance to lithium dendrite growth, and enhanced cyclability
Data Source
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AI summary
The present application concerns solid polymer electrolytes (SPEs) comprising thermoplastic vulcanizates (TPVs) and alkali metal salts, their process of preparation and the electrochemical cells comprising such electrolytes.