Mesoporous Cathode Coating for All-Solid Lithium Sulfur Batteries

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Solution Overview

Problem

Conventional lithium ion batteries face stability issues, low energy density, and polysulfide shuttle phenomena, which hinder their performance as high-capacity batteries for electric vehicles, particularly when using liquid electrolytes.

Innovation Solution

A cathode for all-solid lithium batteries is developed, comprising a lithium composite formed by dispersing a solid electrolyte in the pores of a mesoporous conductor and coating it on a lithium compound (Li2X), where X is a nonmetallic solid like S, Se, or Te, to create a stable ion-electron migration pathway and prevent structural destruction during charging and discharging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a liquid electrolyte is used in lithium sulfur battery, then high energy density can be achieved, but polysulfide shuttle phenomenon occurs causing self-discharge and reduced lifespan

Engineering Contradiction:

Improveenergy densityVSAvoidbattery lifespan

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent changes the physical state of the electrolyte from liquid to solid, fundamentally altering the system's parameters to eliminate polysulfide dissolution and shuttle phenomenon while maintaining high energy density through solid-state ion conduction

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The solid electrolyte acts as an intermediary between the lithium anode and sulfur cathode, enabling ion transport while physically preventing polysulfide dissolution and electrochemical reactions that cause self-discharge

Inventive Principle:

Principle #24Intermediary (Mediator)

2Use of energy by moving object

If a liquid electrolyte is used in lithium sulfur battery, then high energy density can be achieved, but safety issues arise due to instability at high temperatures

Engineering Contradiction:

Improveenergy densityVSAvoidthermal stability

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent changes the electrolyte from liquid to solid state, fundamentally altering thermal properties to achieve high temperature stability while maintaining the energy density benefits of lithium sulfur chemistry

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If conventional lithium ion battery structure is used, then manufacturing simplicity is maintained, but energy density and power are insufficient for electric vehicle applications

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidenergy density

Core Design Contradiction:

Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

The patent employs composite materials including mesoporous conductors, solid electrolytes, and lithium compound coatings to create a cathode structure that achieves high energy density while maintaining manufacturability through established coating and sintering processes

Inventive Principle:

Principle #40Composite materials

4Reliability

If solid electrolyte is dispersed in mesoporous conductor pores, then ion-electron migration pathway is established, but manufacturing complexity increases

Engineering Contradiction:

Improveion migration efficiencyVSAvoidcathode structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent utilizes mesoporous conductor materials with controlled pore structures to naturally accommodate and distribute solid electrolyte particles, creating efficient ion migration pathways through the cathode structure without requiring additional complex manufacturing steps

Inventive Principle:

Principle #31Porous 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

This configuration enhances the long-term stability and efficiency of the battery, prevents the polysulfide shuttle phenomenon, and maintains high energy density without the risks associated with liquid electrolytes, leading to improved battery performance at high temperatures.

Implementation Method 1

a mesoporous conductor having pores

Methodology Applied

Scientific EffectPorosity: Porosity

Implementation Method 2

dispersing a solid electrolyte in the pores of a mesoporous conductor

Methodology Applied

Scientific EffectDispersion: Dispersion (of waves)

Implementation Method 3

coating the solid electrolyte composite on the surface of the lithium compound

Methodology Applied

Scientific EffectCoating: Coatings

Implementation Method 4

maintains high energy density without the risks associated with liquid electrolytes, leading to improved battery performance at high temperatures

Methodology Applied

Scientific EffectStructural stability:

Data Source

PatentUS11177472B2Cathode of all-solid lithium battery and secondary battery using the same

Publication Date: 2021.11.16 HYUNDAI MOTOR CO LTD

AI summary

Disclose are a cathode of an all-solid lithium battery, and a secondary battery system using the same. The cathode includes a lithium composite, and a method of manufacturing the lithium composite comprises: dispersing a solid electrolyte to be uniformly distributed in the pores of a mesoporous conductor to provide a solid electrolyte composite, and coating the solid electrolyte composite on the surface of a lithium compound including nonmetallic solids such as S, Se, and Te.