Solid Electrolyte Composite for Aqueous Lithium-Air Batteries
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Solution Overview
Problem
Current solid electrolytes for lithium or sodium batteries face challenges in maintaining stability and conductivity when in contact with aqueous solutions, particularly in lithium-air batteries, due to issues like brittleness, interfacial resistance, and poor chemical stability.
Innovation Solution
A solid electrolyte comprising a polymer matrix, such as polyvinyl acetal or polyvinyl acetate, doped with lithium or sodium salts, combined with a ceramic filler like NASICON-type ceramics, which enhances mechanical stability and ionic conductivity while preventing chemical reactions with aqueous catholytes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If NASICON-type ceramics (LAGP, LTAP) are used as solid electrolytes, then ionic conductivity is improved, but mechanical brittleness increases leading to cracking risk
Solution Approach 1:
The patent uses composite materials by combining NASICON-type ceramic particles (for ionic conductivity) with a polymer matrix (for mechanical flexibility and stability). This composite structure allows the electrolyte to maintain high Li+ conductivity while gaining the mechanical robustness needed to prevent cracking during assembly and operation.
2Stability of the object's composition
If ceramic electrolytes are used, then chemical stability is improved, but interfacial resistance at electrolyte-electrode interface increases
Solution Approach 1:
The patent introduces a polymer matrix as an intermediary phase between the ceramic particles and the electrode. This polymer layer acts as a mediator that reduces interfacial resistance by providing better contact and compatibility between the rigid ceramic electrolyte and the flexible electrode, while the ceramic particles maintain chemical stability.
3Ease of manufacture
If polymer electrolytes (PEO) are used, then ease of manufacture and flexibility are improved, but chemical stability in aqueous solutions deteriorates
Solution Approach 1:
The patent creates a composite where PEO polymer provides flexibility and ease of manufacture, while NASICON-type ceramic particles provide chemical stability in aqueous solutions. The synergistic combination allows the electrolyte to resist chemical degradation in water-based catholytes while maintaining the processing advantages of polymer materials.
4Reliability
If solid electrolyte membranes are made thinner to reduce resistance, then ionic conductivity is improved, but mechanical strength decreases increasing cracking risk
Solution Approach 1:
The patent changes the physical and chemical parameters of the electrolyte by creating a nanocomposite structure with dispersed ceramic particles in a polymer matrix. This allows the membrane to be made thinner for reduced resistance while the polymer-ceramic composite structure maintains adequate mechanical strength through the synergistic properties of both materials.
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 proposed solid electrolyte achieves improved mechanical stability, extended cycle life, and enhanced ionic conductivity, effectively protecting lithium anodes in aqueous lithium-air batteries and other applications like sodium ion batteries.
Implementation Method 1
A solid electrolyte comprising a polymer matrix, such as polyvinyl acetal or polyvinyl acetate, doped with lithium or sodium salts
Implementation Method 2
combined with a ceramic filler like NASICON-type ceramics, which enhances mechanical stability and ionic conductivity
Data Source
AI summary
The present invention relates to a solid electrolyte comprising a first polymer which is a polyvinyl acetal or polyvinyl acetate, or a copolymer having vinyl acetal and/or vinyl acetate units, doped with a sodium or lithium salt. The solid electrolyte may be used as an ionically conductive membrane in a battery such a Li-air battery.