Ester-Ether Solid Polymer Electrolyte for Dendrite-Resistant Batteries

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Solution Overview

Problem

Conventional lithium-ion batteries using liquid electrolytes face safety and stability issues due to reactions with alkali metals, leading to dendrite formation and potential battery explosions, while solid polymer electrolytes like poly(ethylene oxide) have limited ionic conductivity and electrochemical stability at lower temperatures.

Innovation Solution

A polymer comprising ester and ether repeating units with specific molecular weight and structural configurations, capable of crosslinking to form thermoplastic or thermosetting polymers, is used to create a solid polymer electrolyte with high ionic conductivity and mechanical strength, preventing dendrite formation and enhancing stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If poly(ethylene oxide) is used as solid polymer electrolyte, then ionic conductivity is improved when molten, but mechanical strength and structural stability deteriorate at operating temperatures below melting point

Engineering Contradiction:

Improveionic conductivityVSAvoidoperating temperature range

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The patent uses block copolymer structure combining PEO blocks (for ionic conductivity) with rigid aromatic blocks (for mechanical strength and thermal stability). This composite structure allows the material to maintain both high ionic conductivity and structural integrity at operating temperatures below the PEO melting point, effectively resolving the contradiction between ionic conductivity and temperature stability.

Inventive Principle:

Principle #40Composite materials

2Reliability

If liquid electrolytes are used, then effective solubilizing and ionizing of ionic salts is achieved, but safety and stability deteriorate due to reactions with alkali metals

Engineering Contradiction:

Improveelectrochemical stabilityVSAvoiddendrite formation and battery safety

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the physical state parameter from liquid to solid polymer, and modifies the chemical composition by incorporating rigid aromatic blocks that alter the polymer's interaction with alkali metals. These parameter changes eliminate dendrite formation and improve safety while maintaining electrochemical stability.

Inventive Principle:

Principle #35Parameter changes

3Strength

If crystalline structure of PEO is maintained, then mechanical strength is improved, but ionic transport deteriorates due to difficulty in ionic movement

Engineering Contradiction:

Improvemechanical strengthVSAvoidionic transport

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent segments the polymer into distinct blocks: flexible PEO blocks that provide ionic transport pathways and rigid aromatic blocks that provide mechanical strength. This segmentation allows each block to perform its optimal function without compromising the other, resolving the contradiction between mechanical strength and ionic transport.

Inventive Principle:

Principle #1Segmentation

4Reliability

If polymer architecture is modified to reduce crystallinity, then ionic conductivity is improved, but mechanical strength and structural stability deteriorate

Engineering Contradiction:

Improveionic conductivityVSAvoidmechanical strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The block copolymer structure creates a composite where amorphous PEO blocks provide ionic conductivity while rigid aromatic blocks provide mechanical strength. This composite architecture achieves both high ionic conductivity and mechanical strength simultaneously, resolving the contradiction between reducing crystallinity and maintaining strength.

Inventive Principle:

Principle #40Composite 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 polymer-based solid electrolyte achieves high ionic conductivity at room temperature, maintains mechanical strength, and prevents dendrite formation, improving the safety and efficiency of lithium-ion batteries by allowing for the use of high voltage materials and increased temperature operation.

Implementation Method 1

The ionic conductivity of this polymer is very high (in the order of 10−3 S·cm−1) when the polymer is in the molten state

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 2

A polymer comprising at least one ester repeating unit and one ether repeating unit, capable of crosslinking to form thermoplastic or thermosetting polymers

Methodology Applied

Scientific EffectCrosslinking: Chemical Bonding

Implementation Method 3

The formation of such dendritic structures can be significantly, or even completely inhibited by using polymers with high transport numbers

Methodology Applied

Scientific EffectMechanical constraint: Mechanical Force

Data Source

PatentUS11999811B2Copolymers of ester and ether units, processes for producing same and uses thereof

Publication Date: 2024.06.04 HYDRO QUEBEC CORP

AI summary

The present technology relates to a polymer comprising at least one ester repeating unit and one ether repeating unit for use in an electrochemical cell, particularly in electrochemical accumulators such as lithium batteries, sodium batteries, potassium batteries and lithium-ion batteries. More specifically, the use of this polymer as a solid polymer electrolyte (SPE), as a matrix for forming gel electrolytes, or as a binder in an electrode material are also contemplated.