Fluorinated Polymeric Membrane for Safe Lithium Batteries

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Lithium batteries face safety issues due to the use of flammable and volatile liquid electrolytes, and existing polymeric membranes with organic carbonates as plasticizers have poor mechanical properties and high volatility, necessitating the development of alternative electrolytes that are less flammable, more thermally stable, and cost-effective.

Innovation Solution

A lithium polymeric membrane comprising a fluorinated and semi-crystalline polymeric matrix, lithium salt, and a non-ionic surfactant such as polyethylene glycol tert-octylphenyl ether, which provides improved thermal, electrochemical, and mechanical stability, allowing for higher lithium salt content and similar ionic conductivity to carbonate-based membranes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If liquid electrolytes consisting of lithium salts dissolved in carbonate-based solvents are used, then high ionic conductivity is achieved, but safety problems arise due to flammability and volatility

Engineering Contradiction:

ImprovesafetyVSAvoidionic conductivity

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent changes the physical state of the electrolyte from liquid to solid by using a polymeric matrix, thereby eliminating flammability and volatility while maintaining ionic conductivity through careful selection of polymer composition and plasticizer content

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite polymeric electrolyte system combining a fluorinated polymeric matrix (PVdF-HFP), lithium salts, and non-ionic surfactant plasticizers to achieve both safety (solid state) and high ionic conductivity (through optimized composite composition)

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If organic carbonates are used as plasticizers in polymeric membranes, then ionic conductivity is improved, but mechanical properties deteriorate at high degrees of plasticization

Engineering Contradiction:

Improveionic conductivityVSAvoidmechanical properties

Core Design Contradiction:

Quantity of substanceVSStrength

Solution Approach 1:

The patent uses non-ionic surfactants as alternative plasticizers that provide sufficient ionic conductivity without the severe mechanical property deterioration caused by organic carbonates at high plasticization levels

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent optimizes the composition parameters including polymer-to-plasticizer ratio and lithium salt content to achieve the right balance between ionic conductivity and mechanical integrity in the polymeric membrane

Inventive Principle:

Principle #35Parameter changes

3Quantity of substance

If higher lithium salt content is incorporated to increase ionic conductivity, then electrochemical performance improves, but mechanical integrity may be compromised

Engineering Contradiction:

Improvelithium salt contentVSAvoidmechanical integrity

Core Design Contradiction:

Quantity of substanceVSStrength

Solution Approach 1:

The patent optimizes the lithium salt content parameter within specific ranges (15-30% by weight) to maximize ionic conductivity while the polymeric matrix and plasticizer composition are adjusted to maintain mechanical integrity at these elevated salt concentrations

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 membrane achieves thermal stability up to 200°C, electrochemical stability beyond 4V, and mechanical integrity without breakage, making it suitable for lithium batteries while eliminating flammable substances and maintaining comparable ionic conductivity to carbonate-based systems.

Implementation Method 1

a non-ionic surfactant such as polyethylene glycol tert-octylphenyl ether... which provides improved thermal, electrochemical, and mechanical stability, allowing for higher lithium salt content and similar ionic conductivity to carbonate-based membranes

Methodology Applied

Scientific EffectPlasticization:

Implementation Method 2

lithium batteries that are currently available on the market use liquid electrolytes which consist of lithium salts dissolved in highly flammable solvents

Methodology Applied

Scientific EffectDissolution: Solvation

Implementation Method 3

The membrane achieves thermal stability up to 200°C, electrochemical stability beyond 4V, and mechanical integrity without breakage

Methodology Applied

Scientific EffectThermal stability:

Data Source

PatentEP2860790B1Lithium polymeric membrane based on a semi-crystalline fluorinated polymeric matrix and a non-ionic surfactant

Publication Date: 2017.09.27 INST TECHCO DE LA ENERGIA ITE

Figure 1~2
Figure 3~4

AI summary

Lithium polymeric membrane characterized in that it comprises a fluorinated and semi-crystalline polymeric matrix, a lithium salt and a non-ionic surfactant as a plasticizer. Preferably, it comprises poly(vinyliden fluoride-co-hexafluoropropylene), polyethylene glycol tert-octylphenyl ether and lithium hexafluorophosphate. It also comprises the use of this polymeric membrane as an electrolyte and/or electrical insulator in lithium polymeric batteries.