Conductive Polymer Electrolyte Blend for Solid-State Lithium Batteries

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Solution Overview

Problem

Conventional lithium secondary batteries face safety issues like leakage and explosion due to liquid electrolytes, and existing solid electrolytes have low ionic and electronic conductivity, hindering the development of all-solid-state battery systems.

Innovation Solution

A polymer material comprising a polythiophene-based polymer blended with a conductive polymer, specifically poly-(3,4-ethylenedioxythiophene):poly(styrenesulfonate), is developed, which is heat-treated to enhance ionic and electronic conductivity, allowing it to function as an electrolyte, binder, and conductive material in lithium secondary batteries.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If liquid electrolyte is used in lithium secondary battery, then ionic conductivity is high, but safety problems occur such as leakage, volatilization and explosion

Engineering Contradiction:
ImprovesafetyVSAvoidleakage, volatilization, explosion
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the physical state of the electrolyte from liquid to solid polymer form, fundamentally altering the parameters of the electrolyte system. This transformation eliminates the harmful properties of liquid electrolytes (leakage, volatilization, explosion) while maintaining ionic conductivity through the solid polymer matrix containing lithium salts and conductive polymer components.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite electrolyte system consisting of solid polymer electrolyte combined with conductive polymer components. This composite structure integrates the safety advantages of solid electrolytes with the enhanced conductivity properties of conductive polymers, resolving the contradiction between safety and conductivity.

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 material significantly reduces interfacial resistance and improves battery performance by achieving high ionic and electronic conductivity, making it suitable for all-solid-state batteries and simplifying the manufacturing process.

Implementation Method 1

heat treating the polythiophene-based polymer and the conductive polymer at 120°C to 250°C

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Data Source

PatentEP3664199B1Lithium secondary battery polymer material and manufacturing method therefor
Publication Date: 2023.08.30 LG ENERGY SOLUTION LTD
  • EP3664199B1 patent drawingFigure 1
  • EP3664199B1 patent drawingFigure 2~3
  • EP3664199B1 patent drawingFigure 4

AI summary

The present invention relates to a polymer material for a lithium secondary battery having ionic conductivity and electronic conductivity at the same time, and a method for preparing the same. The polymer material comprises a blend of a polythiophene-based polymer and a conductive polymer, and the polymer material may be formed by forming a polythiophene-based polymer, forming a conductive polymer, and heat-treating the polythiophene-based polymer and the conductive polymer.