Polymer Electrode with Conductive Coating for High Energy Density

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Solution Overview

Problem

Lithium secondary batteries using polymer electrolytes exhibit lower ion conductivity and interfacial resistance, leading to degraded output and capacity characteristics, especially at low temperatures, and are limited in achieving high energy density and wide voltage capabilities due to the non-reactive nature of solid electrolytes with electrode active materials.

Innovation Solution

The electrode design involves a conductive material coated on the surface of electrode active material particles, with a first polymer electrolyte coating and a second polymer electrolyte layer to increase reactive sites and reduce the amount of conductive material needed, while incorporating anti-oxidizing and anti-reducing agents to enhance electrochemical stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a polymer electrolyte is used to ensure safety and prevent leakage, then safety and reliability are improved, but ion conductivity decreases and output characteristics are degraded

Engineering Contradiction:
ImprovesafetyVSAvoidion conductivity
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The patent uses a composite structure combining polymer electrolyte with conductive material particles (such as carbon black, graphite, or metal particles) dispersed within the polymer matrix. This composite approach maintains the safety advantages of polymer electrolytes while introducing conductive pathways that enhance ion conductivity and output characteristics without sacrificing the inherent safety benefits

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The conductive material is distributed locally within the polymer electrolyte structure, creating regions of enhanced conductivity where needed. The conductive particles form localized conductive networks or pathways that facilitate ion transport at critical interfaces while the bulk polymer electrolyte maintains its safety properties

Inventive Principle:
Principle #3Local quality

2Reliability

If solid polymer electrolyte is used, then safety is improved, but adhesion to active material surface decreases and interfacial resistance increases

Engineering Contradiction:
ImprovesafetyVSAvoidinterfacial resistance
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The conductive material particles serve as interfacial bridges between the polymer electrolyte and active material surfaces. These particles improve wetting and adhesion by creating favorable surface energy conditions and physical contact points, thereby reducing interfacial resistance while maintaining the safety advantages of the solid polymer electrolyte

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The conductive material acts as an intermediary substance at the interface between the polymer electrolyte and active material. It mediates the interaction by improving contact and reducing resistance at this critical interface, enabling better electrochemical performance without compromising the safety provided by the solid polymer electrolyte

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If solid polymer electrolyte is used, then safety is improved, but fluidity decreases and reactive contact with active material is reduced

Engineering Contradiction:
ImprovesafetyVSAvoidcapacity characteristics
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The conductive material particles create a percolating network or dispersed pathways within the solid polymer electrolyte, enabling ion transport without requiring bulk fluidity. This allows the solid polymer electrolyte to maintain its safety advantages while achieving sufficient ionic conductivity through the conductive particle network for high capacity characteristics

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent replaces the mechanical fluidity mechanism of liquid electrolytes with an alternative conduction mechanism based on conductive particle networks within the solid polymer matrix. Instead of relying on fluid flow for ion transport, the system uses the conductive particles to provide pathways for ionic conduction, eliminating the need for fluidity while maintaining productivity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If polymer electrolyte is used, then safety is improved, but redox stability decreases and electrolyte deterioration accelerates

Engineering Contradiction:
ImprovesafetyVSAvoidredox stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The conductive material particles serve as protective intermediaries between the polymer electrolyte and active material surfaces. They form a protective barrier that prevents direct contact and reduces the intensity of redox reactions at the interface, thereby improving redox stability and preventing electrolyte deterioration while maintaining the safety advantages of the polymer electrolyte

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The conductive material is incorporated into the polymer electrolyte structure in advance to provide protective cushioning against harmful redox reactions. This pre-established protective network mitigates the impact of redox reactions before they can cause significant electrolyte deterioration, enabling the use of polymer electrolytes with improved redox stability

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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

This approach improves electroconductivity, reduces the need for high-pressure processing, and enhances output characteristics and energy density, preventing electrode material deterioration and maintaining stability during redox reactions.

Implementation Method 1

a conductive material coating a surface of electrode active material particles

Methodology Applied
Scientific EffectConduction: Conduction (electrical)

Implementation Method 2

a first polymer electrolyte coating the conductive material and electrode active material particles, and a second polymer electrolyte layer covering the first polymer electrolyte

Methodology Applied
Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 3

maintaining stability during redox reactions

Methodology Applied
Scientific EffectRedox reactions: Redox Reactions

Implementation Method 4

incorporating anti-oxidizing and anti-reducing agents to enhance electrochemical stability

Methodology Applied
Scientific EffectOxidation prevention: Oxidation

Implementation Method 5

incorporating anti-oxidizing and anti-reducing agents to enhance electrochemical stability

Methodology Applied
Scientific EffectReduction prevention: Reduction

Data Source

PatentEP3467907B1Method for manufacturing electrode including polymer electrolyte and electrode obtained thereby
Publication Date: 2021.11.03 LG ENERGY SOLUTION LTD
  • EP3467907B1 patent drawingFigure 1~3
  • EP3467907B1 patent drawingFigure 4

AI summary

The present disclosure relates to a method for manufacturing an electrode including a polymer electrolyte and an electrode obtained thereby. Particularly, the present disclosure relates to an electrode for a wide voltage battery which has improved reactivity on the surface of the electrode active material. The electrode provides an increased reactive site between an electrode active material and a polymer electrolyte and an improved ratio of the amount of active material in the electrode, and thus can provide a battery with improved energy density.