Comb Polymer Solid Electrolyte for Low-Temperature Lithium Conduction
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Solution Overview
Problem
Existing polymer electrolytes for lithium batteries suffer from limited ionic conductivity and electrochemical stability, particularly at low temperatures, and require high operating temperatures due to crystallization, while solid polymer electrolytes with improved mechanical performance are needed to address safety and cost issues.
Innovation Solution
A comb polymer electrolyte with a main chain formed from 1-ethenyl- and/or 1-allyl-2,3,4,5,6-pentafluorobenzene monomers and polymeric side chains grafted in para pentafluorophenyl groups, combined with alkali or alkaline-earth metal salts, forms a solid electrolyte film that exhibits high ionic conductivity and mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional liquid electrolytes are used, then good ionic conductivity is achieved, but safety and thermal stability problems occur
Solution Approach 1:
The patent changes the physical state parameter of the electrolyte from liquid to solid by using a comb polymer matrix, thereby maintaining ionic conductivity while improving safety and thermal stability. The solid polymer electrolyte eliminates the need for flammable liquid solvents while preserving ion transport capability through the polymer's molecular structure.
Solution Approach 2:
The patent creates a composite solid polymer electrolyte system combining the comb polymer matrix with lithium salts (such as LiTFSI). This composite structure integrates the mechanical stability and thermal resistance of the polymer with the ionic conductivity provided by the lithium salt, resolving the contradiction between safety and ionic conductivity.
2Object-affected harmful factors
If poly(oxyethylene) based solid polymer electrolytes are used, then safety issues are addressed, but ionic conductivity is limited
Solution Approach 1:
The patent applies local quality by creating distinct functional regions within the polymer structure: the main chain provides mechanical stability and safety, while the grafted polymeric side chains (containing ether oxygens) locally concentrate ionic conduction pathways. This spatial separation of functions allows the solid polymer to achieve both safety and high ionic conductivity simultaneously.
3Adaptability or versatility
If polymer electrolytes are used at low temperatures, then operational flexibility is improved, but ionic conductivity decreases
Solution Approach 1:
The patent modifies the molecular architecture parameter by introducing comb-shaped polymeric side chains with ether oxygens that remain flexible at low temperatures. This structural parameter change allows the electrolyte to maintain low glass transition temperature and high chain mobility, thereby preserving ionic conductivity across a wide temperature range from -40°C to 60°C.
4Strength
If mechanical stability is improved in solid polymer electrolytes, then safety is enhanced, but ionic conductivity may be reduced
Solution Approach 1:
The patent segments the polymer structure into a rigid main chain (poly(2,3,4,5,6-pentafluorostyrene)) that provides mechanical stability and a flexible side chain (poly(ethylene oxide)) that provides ionic conductivity. This segmentation allows each part to optimize its function without compromising the other, as the side chains can move independently within the constraints of the stable main chain framework.
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 comb polymer electrolyte achieves ionic conductivity of at least 10^-6 S.cm^-1 at 60°C, with good electrochemical stability and mechanical integrity, enabling wide temperature operation and compatibility with high-energy density batteries.
Implementation Method 1
polymeric side chains based on polymers which are solvents of alkali or alkaline-earth metal salts
Implementation Method 2
The transport of the proton or the alkali or alkaline-earth cation, in particular the lithium cation, between the positive electrode and the negative electrode, is ensured by an ionic conductive electrolyte
Data Source
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AI summary
The present invention relates to a solid polymeric electrolyte comprising: - at least one comb polymer including a main chain formed from 1-ethenyl- and/or 1-allyl- 2,3,4,5,6-pentafluorobenzene monomers, a portion of the monomeric units of the main chain bearing polymeric side chains based on solvent polymers of alkali or alkaline earth metal salts, said chains being para-grafted to pentafluorophenyl groups; and - at least one alkali or alkaline earth metal salt, in particular a lithium salt. It also relates to a method for preparing a solid polymeric electrolyte film and its implementation in an electrochemical system, in particular a lithium battery.