Silicone Polyether Solid Polymer Electrolyte Film for Battery Safety
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Solution Overview
Problem
Conventional liquid electrolytes in lithium ion batteries face issues such as leakage, flammability, and limited life cycles, which pose safety and efficiency concerns, while solid polymer electrolytes using porous poly(vinylidene) fluoride films have flammability hazards and limited life cycles.
Innovation Solution
A cross-linkable silicone polyether with a methyl siloxane backbone and alkoxy-terminated polyether side chains is used to form a hydrogel copolymer, combined with a plasticizer and salt, to create a solid polymer electrolyte film with controlled cross-linking density for enhanced mechanical strength and ionic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid electrolytes are used in lithium ion batteries, then ionic conductivity is achieved, but leakage and flammability problems occur
Solution Approach 1:
The patent transitions the electrolyte from liquid phase to solid gel phase by incorporating a cross-linkable polyether component that forms a three-dimensional network structure. This phase transition eliminates leakage while maintaining ionic conductivity through the gel structure, and the cross-linked network reduces flammability compared to liquid electrolytes.
Solution Approach 2:
The patent creates a composite gel electrolyte system combining cross-linkable polyether (forming the gel network), plasticizer (enhancing ionic conductivity), and lithium salt (providing ions). This composite approach integrates the advantages of solid polymers (structural integrity, no leakage) with liquid electrolytes (high ionic conductivity).
2Strength
If porous poly(vinylidene) fluoride films are used as solid polymer electrolytes, then mechanical strength is provided, but flammability hazards and limited life cycles remain
Solution Approach 1:
The patent changes the chemical composition parameters by replacing poly(vinylidene) fluoride with cross-linkable polyether containing alkoxy-terminated side chains. This parameter change maintains mechanical strength through cross-linking while improving safety by eliminating the flammability issues associated with PVdF and organic carbonate solvents.
3Strength
If cross-linking density is increased in the silicone polyether, then mechanical strength improves, but ionic conductivity may be reduced
Solution Approach 1:
The patent employs local quality by creating regions of different cross-linking densities within the gel network. The cross-linkable polyether forms a three-dimensional network with variable density, allowing dense cross-linked regions for mechanical strength while maintaining less dense regions that facilitate ion transport, thus balancing both properties.
Solution Approach 2:
The patent uses plasticizer as a parameter adjustment mechanism to maintain ionic conductivity despite increased cross-linking density. The plasticizer components fill the network voids and provide pathways for ion movement, compensating for the reduced conductivity that would result from higher cross-linking density 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 resulting solid polymer electrolyte film exhibits high ionic conductivity and mechanical strength, offering improved safety and durability for lithium ion batteries, with flexibility in design and application across various sizes and shapes.
Implementation Method 1
a cross-linkable network of the silicone polyether with a monomer
Implementation Method 2
The hydrogel copolymer comprises a cross-linked network of the silicone polyether with a monomer
Implementation Method 3
The solid polymer electrolyte comprises a film formed from the hydrogel copolymer, a plasticizer, and a salt. The solid polymer electrolyte composition has a high ionic conductivity
Data Source
AI summary
A copolymer suitable for use in forming a solid polymer electrolyte film comprising a first monomer represented by Formula (1):wherein n is 2 to 1,000; m is 2 to 1,000; x and y are individually 1 to 100; p is 0 to 10; and q is 1 to 10, R1 is an alkyl group having 1 to 10 carbon atoms, and A is an alkyl acryloyl group an acryloyl group, alkyl acryloyl group, methacryloyl group, alkyl methacryloyl group, a vinyl group, an allyl group, a styryl group, or a combination of two or more thereof; and a second monomer chosen from a hydroxyl-substituted alkyl acrylate, a hydroxyl-substituted alkyl methacrylate, or a combination of two or more thereof. The copolymer may be used to form a solid polymer electrolyte composition comprising (i) the copolymer, (ii) a plasticizer, and (iii) a salt. The solid polymer electrolyte may be used to form a solid polymer electrolyte film, which may be suitable for use in electrochemical devices.