Gelled Polymer Electrolyte via Ionic Liquid Electro-grafting

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Solution Overview

Problem

Conventional lithium batteries face limitations due to the low ionic conductivity of polymer electrolytes at room temperature and the use of flammable solvents in gelled electrolyte synthesis, which affects safety and operational temperature ranges.

Innovation Solution

A method for synthesizing a gelled polymer electrolyte directly on the surface of a lithium battery electrode using electro-grafting of an ionic liquid monomer followed by gelation with a dinitrile compound, eliminating the need for solvents and enhancing ionic conductivity and adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If polymer electrolyte films are deposited by dissolving polymer in solvent and drying, then the electrolyte film can be formed, but flammable and toxic solvents must be used

Engineering Contradiction:
Improveelectrolyte film formationVSAvoidflammability and toxicity of solvents
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The invention extracts and eliminates the solvent from the electrolyte film formation process. Instead of dissolving polymer in solvent and drying, the method uses electro-grafting to deposit polymer directly from ionic liquid monomers onto the electrode surface, completely removing the need for flammable and toxic organic solvents while maintaining film formation capability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the chemical state and composition of the electrolyte precursor from conventional organic solvents to ionic liquids. This parameter change allows the electrolyte to be formed through electrochemical polymerization of ionic liquid monomers, eliminating flammability and toxicity while enabling direct deposition on electrode surfaces

Inventive Principle:
Principle #35Parameter changes

2Strength

If the gelled electrolyte is applied directly on electrode surface by electro-grafting, then the adhesion is improved, but the process complexity increases

Engineering Contradiction:
Improveadhesion of electrolyte to electrodeVSAvoidelectro-grafting process
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The invention employs self-service by using the electrode itself as the substrate for electro-grafting. The electrode surface serves as the site for polymerization, automatically forming strong covalent bonds between the polymer and electrode without requiring separate adhesion layers or additional processing steps

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention replaces mechanical adhesion methods (such as lamination or physical coating) with electrochemical bonding. Through electro-grafting, covalent bonds are formed between the polymer chains and the electrode surface, providing superior adhesion strength without the complexity of mechanical assembly processes

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 approach results in a thin, uniformly coated gelled electrolyte with improved ionic conductivity and electronic insulation, reducing migration resistance and eliminating the risk of flammable solvent use, while maintaining low thickness for efficient battery operation.

Implementation Method 1

electro-grafting of a polymeric film, from an ionic liquid monomer whose cation carries at least one electro-polymerizable function

Methodology Applied
Scientific EffectElectrochemical polymerization: Electroplating

Implementation Method 2

gelling said polymeric film by adding a solution of lithium salt in a dinitrile compound

Methodology Applied
Scientific EffectGelation: Gel

Implementation Method 3

The presence of the electrolyte ensures the transport of lithium ions between the electrodes during charging and discharging of the battery

Methodology Applied
Scientific EffectIonic conduction: Conduction (electrical)

Data Source

PatentEP3629413B1Gel electrolyte, method for preparation and use of the gel electrolyte
Publication Date: 2022.12.21 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP3629413B1 patent drawingFigure 1a~2
  • EP3629413B1 patent drawingFigure 3~4
  • EP3629413B1 patent drawingFigure 5-a~5-b

AI summary

The invention relates to a method for functionalizing the electrically conductive or semiconducting surface of an electrode by electrografting a polymeric film obtained from an ionic liquid monomer whose cation carries at least one electropolymerizable function. It further relates to a method for preparing a gelled electrolytic membrane on the surface of an electrode by gelling the electrografted polymeric film, as well as the use of the resulting electrode/electrolytic membrane assembly in a lithium battery.