Comb Polymer Electrolyte for Low-Temperature Ion Conductivity

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Solution Overview

Problem

Conventional lithium battery electrolytes face limitations in ion conductivity and electrochemical stability, especially at low temperatures, due to polymer crystallization, and existing solid polymer electrolytes lack both mechanical performance and high ion conduction.

Innovation Solution

A comb polymer 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 the para position of pentafluorophenyl groups, using polymeric side chains based on solvent polymers of alkali metal or alkaline-earth metals, such as poly(ethylene oxide), to form a solid polymer electrolyte.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If poly(oxyethylene) based solid polymer electrolytes are used, then electrochemical stability is improved, but ion conductivity deteriorates at temperatures below 60°C due to polymer crystallization

Engineering Contradiction:

Improveelectrochemical stabilityVSAvoidion conductivity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent combines poly(oxyethylene) chains (providing electrochemical stability) with poly(tert-butyl 2-((2-bromopropionyloxy)methyl)acrylate) main chain (preventing crystallization) to create a composite polymer electrolyte that achieves both high electrochemical stability and maintained ion conductivity at low temperatures

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent modifies the physical state of the polymer electrolyte by incorporating a amorphous polymer main chain that prevents crystallization, thereby maintaining ion conductivity at temperatures below 60°C while preserving the electrochemical stability provided by poly(oxyethylene) side chains

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If poly(trimethylene carbonate) based polymers are used, then ion conductivity is improved, but mechanical performance deteriorates

Engineering Contradiction:

Improveion conductivityVSAvoidmechanical performance

Core Design Contradiction:

Manufacturing precisionVSStrength

Solution Approach 1:

The patent divides the polymer structure into distinct functional segments: the poly(tert-butyl 2-((2-bromopropionyloxy)methyl)acrylate) main chain provides mechanical strength, while poly(oxyethylene) side chains provide ion conductivity pathways, allowing each segment to optimize its specific function

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent assigns different local properties to different parts of the polymer structure: the main chain is designed for mechanical performance with appropriate rigidity and strength, while the grafted side chains are designed for ion solvation and conductivity, creating local optimization of functions

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If conventional liquid electrolytes are used, then ion conductivity is improved, but safety and thermal stability deteriorate

Engineering Contradiction:

Improveion conductivityVSAvoidsafety and thermal stability

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the liquid electrolyte system with a solid polymer electrolyte system, eliminating the need for separate mechanical separators and reducing safety hazards associated with liquid solvents while maintaining ion conductivity through the amorphous polymer matrix with solvating side chains

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 comb polymer electrolyte exhibits excellent ion conductivity (≥10−6 S·cm−1 at 60°C) and good electrochemical cycling stability, enabling lithium batteries to function over a wide temperature range without compromising mechanical integrity.

Implementation Method 1

using polymeric side chains based on solvent polymers of alkali metal or alkaline-earth metals, such as poly(ethylene oxide), to form a solid polymer electrolyte

Methodology Applied

Scientific EffectSolvation: Solvation

Implementation Method 2

Conventional lithium battery electrolytes face limitations in ion conductivity and electrochemical stability, especially at low temperatures, due to polymer crystallization

Methodology Applied

Scientific EffectCrystallization: Crystallisation

Implementation Method 3

The electrolyte's ion conductivity especially determines the efficiency of the electrochemical system given that it influences the mobility of the ions between the positive and negative electrodes

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Data Source

PatentUS12006385B2Comb polymer

Publication Date: 2024.06.11 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES

AI summary

The present invention relates to a comb polymer comprising a main chain formed from 1-ethenyl- and/or 1-allyl-2,3,4,5,6-pentafluorobenzene monomers and polymeric side chains grafted in the para position of the pentafluorophenyl groups, in which said polymeric side chains are linked to said main chain by an oxygen atom, the molar grafting rate of polymeric side chains being greater than or equal to 50%.It also relates to a method for the preparation of such a comb polymer.