TPV Solid Polymer Electrolyte Composition for Lithium Dendrite Resistance
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Solution Overview
Problem
Solid-state batteries face challenges with lithium dendrite growth, limited lifetime, and safety issues due to low ionic conductivity and mechanical integrity, particularly in polymer electrolytes that are not reprocessable and lack elastic properties.
Innovation Solution
Development of thermoplastic vulcanizates (TPV) based solid polymer electrolytes (SPEs) comprising a crosslinked elastomer phase and a thermoplastic polymer phase, with specific ratios and additives like lithium salts and dopants, to enhance ionic conductivity and mechanical strength, and a cost-effective industrial production process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymer electrolytes are used to replace liquid electrolytes for safety, then safety is improved, but ionic conductivity decreases leading to limited power range
Solution Approach 1:
The patent uses a composite polymer electrolyte system combining PEO (polyethylene oxide) as the base polymer with HNBR (hydrogenated nitrile butadiene rubber) as an additive. This composite structure leverages the high ionic conductivity of PEO while HNBR enhances mechanical strength and safety, achieving both improved safety and maintained ionic conductivity through synergistic material combination.
2Reliability
If polymer electrolytes are used to replace liquid electrolytes, then safety is improved, but mechanical integrity decreases due to lithium dendrite growth
Solution Approach 1:
The composite PEO-HNBR electrolyte system provides enhanced mechanical integrity through the reinforcing effect of HNBR particles distributed within the PEO matrix. This composite structure resists lithium dendrite penetration better than pure PEO while maintaining the safety benefits of solid polymer electrolytes.
Solution Approach 2:
The patent optimizes the concentration of HNBR additive and lithium salt content to achieve the right balance between mechanical strength and ionic conductivity. By adjusting these parameters, the electrolyte gains sufficient mechanical rigidity to prevent dendrite growth while maintaining adequate ion transport capability.
3Strength
If crosslinked polymer systems are used to improve mechanical strength, then mechanical strength is improved, but reprocessability is lost
Solution Approach 1:
Instead of complete crosslinking that would eliminate reprocessability, the patent uses a partial crosslinking approach with HNBR as an additive rather than a crosslinking agent. This provides sufficient mechanical reinforcement while leaving the majority of the PEO matrix uncrosslinked and reprocessable, achieving a balance between strength and manufacturing flexibility.
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, resistance to lithium dendrite growth, high mechanical strength, and excellent cyclability, making them suitable for high-energy applications with enhanced safety and scalability.
Implementation Method 1
They are based on the reversible exchange of the lithium ion between the positive and negative electrodes, separated by an ionic conductive liquid electrolyte
Implementation Method 2
wherein said TPV comprises a mixture of at least one crosslinked elastomer phase and at least one thermoplastic polymer phase
Data Source
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.