Bilayer Lithium Garnet Electrolyte for Stable Battery Interfaces

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Solution Overview

Problem

Solid-state lithium batteries face challenges with elemental inter-diffusion and mechanical degradation at the solid electrolyte-positive electrode interface due to volume changes during charging and discharging, which affect the mechanical integrity of the interface.

Innovation Solution

A bilayer component is introduced, comprising a dense, nonporous lithium garnet layer adjacent to the lithium metal negative electrode and a porous layer proximate to the positive electrode, with an ionic liquid present in the pores of the porous layer to stabilize the interface and accommodate volume changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a solid-state electrolyte is used to improve safety and energy density, then battery performance is improved, but mechanical integrity at the interface deteriorates due to volume changes during charging and discharging

Engineering Contradiction:

Improveenergy densityVSAvoidmechanical integrity of interface

Core Design Contradiction:

Use of energy by moving objectVSStrength

Solution Approach 1:

The solid electrolyte is divided into two distinct layers: a dense layer adjacent to the lithium metal negative electrode and a porous layer adjacent to the positive electrode. This segmentation allows each layer to perform specialized functions - the dense layer provides high ionic conductivity and stability at the lithium interface, while the porous layer accommodates volume changes and prevents mechanical degradation at the positive electrode interface.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the solid electrolyte are given different properties. The dense layer has high density and high ionic conductivity optimized for the lithium metal interface, while the porous layer has lower density and porosity optimized for accommodating volume changes at the positive electrode interface. This local differentiation resolves the contradiction by matching material properties to local operational requirements.

Inventive Principle:

Principle #3Local quality

2Stability of the object's composition

If a dense, nonporous lithium garnet layer is used adjacent to the lithium metal negative electrode to improve stability, then interface stability is improved, but ionic conductivity may be limited

Engineering Contradiction:

Improveinterface stabilityVSAvoidionic conductivity

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The electrolyte is segmented into dense and porous layers, with the dense layer providing stability at the lithium interface and the porous layer providing high ionic conductivity pathways. This segmentation allows both stability and conductivity requirements to be satisfied in different regions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The solid electrolyte functions as a composite structure combining dense lithium garnet material (for stability) with a porous framework (for ion transport). This composite approach integrates the advantages of both dense and porous structures, achieving both interface stability and high ionic conductivity.

Inventive Principle:

Principle #40Composite materials

3Strength

If a porous layer is used proximate to the positive electrode to accommodate volume changes, then mechanical integrity is improved, but density is reduced

Engineering Contradiction:

Improvemechanical integrityVSAvoiddensity

Core Design Contradiction:

StrengthVSVolume of stationary object

Solution Approach 1:

The porous layer is specifically positioned at the positive electrode interface where volume changes occur during cycling. This local placement allows the porous structure to accommodate mechanical stress while the dense layer maintains overall electrolyte density and ionic conductivity. Each layer's properties are optimized for its specific functional role.

Inventive Principle:

Principle #3Local quality

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 bilayer component enhances the mechanical integrity and stability of the solid-state electrolyte-positive electrode interface, preventing elemental inter-diffusion and improving the mechanical integrity of the interface.

Implementation Method 1

volume changes that effect the mechanical integrity of the solid electrolyte-positive electrode interface

Methodology Applied

Scientific EffectVolume change accommodation:

Implementation Method 2

diffusion of elements between the positive electrode and a solid-state electrolyte

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Data Source

PatentUS20250253393A1Bilayer component for a lithium battery

Publication Date: 2025.08.07 SAMSUNG ELECTRONICS CO LTD

AI summary

A component for a lithium battery including a first layer including a lithium garnet having a porosity of 0 percent to less than 25 percent, based on a total volume of the first layer, and a second layer on the first layer and having a porosity of 25 percent to 80 percent, based on a total volume of the second layer, wherein the second layer is on the first layer and the second layer has a composition that is different from a composition of the first layer.