Garnet Oxide Solid Electrolyte for Room-Temperature Ionic Conductivity

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Solution Overview

Problem

Lithium secondary batteries with liquid electrolytes pose safety risks due to flammability, and while all-solid-state batteries with sulfide-based electrolytes offer improved safety, the oxide-based electrolytes have low ionic conductivity at room temperature, necessitating a more effective oxide-based solid electrolyte with enhanced ionic conductivity.

Innovation Solution

A method to prepare an oxide with improved ionic conductivity by heat-treating a precursor mixture containing lithium and multiple element precursors, forming a compound with a garnet structure that stabilizes the cubic phase, thereby maintaining lithium levels and increasing configuration entropy, which enhances ionic conductivity and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If lithium level is increased to improve ionic conductivity, then ionic conductivity improves, but structural stability may deteriorate

Engineering Contradiction:

Improveionic conductivityVSAvoidstructural stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent optimizes the lithium content parameter x within the specific range of 6≤x≤8, avoiding excessive lithium addition. This controlled parameter adjustment ensures high ionic conductivity through adequate lithium concentration while preventing structural degradation that would occur with过高 lithium content, thus resolving the contradiction between ionic conductivity and structural stability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by distributing lithium and other elements (M1, M2, M3) in specific stoichiometric ratios within different regions of the garnet structure. This localized compositional optimization ensures that lithium is present in sufficient quantities for high ionic conductivity in the conduction pathways, while maintaining overall structural stability through balanced element distribution throughout the crystal lattice.

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 resulting oxide-based solid electrolyte exhibits high ionic conductivity at room temperature, reducing internal resistance in electrochemical batteries and improving lithium stability, making it suitable for next-generation battery applications.

Implementation Method 1

heat-treating the precursor mixture in an oxidizing gas to prepare a compound represented by Formula 1

Methodology Applied

Scientific EffectHeat treatment: Heat Treatment

Implementation Method 2

heat-treating the precursor mixture in an oxidizing gas

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS11837695B2Oxide, method of preparing the same, solid electrolyte including the oxide, and electrochemical device including the oxide

Publication Date: 2023.12.05 SAMSUNG ELECTRONICS CO LTD

AI summary

An oxide including a compound represented by Formula 1:(LixM1y)(M2)3-δ(M3)2-ωO12-zXz Formula 1wherein, in Formula 1,6≤x≤8, 0≤y<2, −0.2≤δ≤0.2, −0.2≤ω≤0.2, and 0≤z≤2;M1 is a monovalent cation, a divalent cation, a trivalent cation, or a combination thereof;M2 is a monovalent cation, a divalent cation, a trivalent cation, or a combination thereof;M3 is a monovalent cation, a divalent cation, a trivalent cation, a tetravalent cation, a pentavalent cation, a hexavalent cation, or a combination thereof;wherein at least one of M1, M2, or M3 includes at least four elements; andX is a monovalent anion, a divalent anion, a trivalent anion, or a combination thereof.