Fluoropolymer Composite Separator Films for Low-Temperature Ionic Conductivity

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Solution Overview

Problem

Lithium metal polymer batteries face a challenge with low ionic conductivity of separators at temperatures below 80° C, making existing extrusion technologies less attractive and unsafe for electrode separation.

Innovation Solution

A process for manufacturing a fluoropolymer hybrid organic/inorganic composite is developed, involving the processing of a pre-composite and poly(alkylene oxide) in a molten phase using extrusion, which enhances ionic conductivity and ensures safe electrode separation by creating dense, pore-free films suitable for electrochemical and photo-electrochemical applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If film extrusion is used to manufacture separators, then manufacturing simplicity is maintained, but ionic conductivity remains low at temperatures below 80° C

Engineering Contradiction:

Improveionic conductivityVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs a composite material system comprising a poly(alkylene oxide) matrix combined with a fluoropolymer and inorganic filler particles. This composite structure enables the separator to achieve high ionic conductivity through the poly(alkylene oxide) phase while maintaining processability through the fluoropolymer component, thereby resolving the contradiction between improved ionic conductivity and ease of manufacture

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent utilizes parameter changes by controlling the crystallization behavior of poly(alkylene oxide) through the addition of fluoropolymer and inorganic fillers. By modifying the crystallization temperature and degree of crystallinity parameters, the material achieves optimal ionic conductivity at lower temperatures while remaining manufacturable through standard extrusion processes

Inventive Principle:

Principle #35Parameter changes

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 process results in films with outstanding ionic conductivity, suitable for use as separators in electrochemical devices, particularly lithium-ion batteries, improving their performance and safety by maintaining high conductivity across a broader temperature range.

Implementation Method 1

at least partial hydrolysis and/or polycondensation, in the presence of a liquid medium, of at least one metal compound (M) of formula (I)

Methodology Applied

Scientific EffectHydrolysis: Hydrolysis

Implementation Method 2

processing in molten phase, preferably extruding the composition provided in step (ii)

Methodology Applied

Scientific EffectExtrusion: Extrusion

Data Source

PatentUS11820889B2Fluoropolymer hybrid composite

Publication Date: 2023.11.21 SYENSQO SA

AI summary

The present invention pertains to a fluoropolymer hybrid organic/inorganic composite, to a film comprising said fluoropolymer hybrid organic/inorganic composite and to uses of said film in various applications, especially in electrochemical and in photo-electrochemical applications.