LiOH-Li2SO4 Solid Electrolyte for Room-Temperature Ion Transport

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing solid electrolytes lack sufficient lithium ion conductivity over a wide temperature range from room temperature to high temperature, limiting their performance in electric storage devices.

Innovation Solution

A solid electrolyte composition of 3LiOH·Li2SO4 with a lithium ion conductivity of 0.1×10−6 S/cm or more at 25° C. and an activation energy of 0.6 eV or more is developed, achieved through a method involving the cooling and grinding of a melt with a specific feedstock composition, followed by shaping and melting processes to enhance conductivity and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a solidified material produced by homogenously melting and quenching Li2SO4 and LiOH is used, then the solid electrolyte can be used in a device operable at low temperature, but the lithium ion conductivity at room temperature is not sufficiently high

Engineering Contradiction:

Improveoperability at low temperatureVSAvoidlithium ion conductivity at room temperature

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The invention changes the compositional parameters by introducing a specific ratio range of LiOH to Li2SO4 (0.4 ≤ LiOH/(LiOH+Li2SO4) ≤ 0.8), and controls the cooling rate parameter during solidification to achieve the optimal balance between low-temperature operability and room-temperature conductivity. This parameter optimization resolves the contradiction by finding the precise conditions where both requirements are satisfied.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If the lithium ion conductivity is less temperature-dependent, then the solid electrolyte maintains stable performance, but an increase in lithium ion conductivity with an increase in temperature cannot be expected

Engineering Contradiction:

Improvetemperature independence of conductivityVSAvoidlithium ion conductivity at high temperature

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The invention creates a composite solid electrolyte system combining LiOH and Li2SO4 in specific proportions, where the interaction between these two components produces a material with optimized thermal behavior. The composite structure allows the material to maintain stability while achieving sufficient conductivity enhancement at elevated temperatures, resolving the contradiction between stability and temperature-dependent performance.

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 solid electrolyte maintains high lithium ion conductivity over a wide temperature range, improving the performance of electric storage devices by ensuring sufficient conductivity at both room and high temperatures.

Implementation Method 1

cooling a melt having a feedstock composition expressed by a formula xLiOH·yLi2SO4 to form a solidified material

Methodology Applied

Scientific EffectFreezing: Freezing

Implementation Method 2

the solid electrolyte has a lithium ion conductivity of 0.1×10−6 S/cm or more at 25° C.

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentUS11855254B2Solid electrolyte

Publication Date: 2023.12.26 NGK INSULATORS LTD

AI summary

Provided is a solid electrolyte which contains a composition expressed by 3LiOH·Li2SO4. The solid electrolyte has a lithium ion conductivity of 0.1×10−6 S/cm or more at 25° C. and an activation energy of 0.6 eV or more.