Crystalline Solid Electrolyte for Air-Stable Ion Conduction

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Solution Overview

Problem

Existing solid secondary batteries face challenges with solid electrolytes that have low ionic conductivity and poor formability, leading to non-uniform contact between the cathode and the oxide-based solid electrolyte, which affects battery performance and safety.

Innovation Solution

A novel solid electrolyte composed of a crystalline composite, specifically a compound represented by Formula 1 or Formula 2, or a combination thereof, is developed. This composite is formed by mechanochemically mixing lithium hydroxide and metal fluoride at a specific molar ratio, enhancing ion conductivity and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sulfide-based solid electrolyte is used to achieve high ion conductivity, then ionic conductivity is improved, but sulfide gas is generated when exposed to air reducing safety

Engineering Contradiction:

Improveionic conductivityVSAvoidsulfide gas generation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent employs composite materials by combining oxide-based solid electrolyte particles with conductive carbon particles. The oxide-based solid electrolyte provides air stability and safety, while the conductive carbon particles form a three-dimensional conductive network that compensates for the lower intrinsic ionic conductivity of oxides, achieving high overall ion conductivity without sulfide gas generation.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent optimizes the content of conductive particles within a specific range (0.1-10 wt% based on total electrolyte weight) and controls the particle size distribution to create an effective conductive network. By adjusting these parameters, the composite achieves optimal balance between ionic conductivity and air stability.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If oxide-based solid electrolyte is used to ensure air stability, then safety is improved, but ionic conductivity and formability are reduced

Engineering Contradiction:

Improveair stabilityVSAvoidionic conductivity

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent creates a composite structure where oxide-based solid electrolyte particles are embedded in a conductive carbon particle network. This composite approach allows the oxide to maintain air stability while the carbon conductive network enhances overall ionic conductivity and improves formability for uniform electrode contact.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent introduces local conductive regions by dispersing conductive carbon particles throughout the oxide-based solid electrolyte matrix. This creates localized conductive pathways that improve overall ionic transport without compromising the bulk air stability of the oxide-based electrolyte.

Inventive Principle:

Principle #3Local quality

3Reliability

If grain boundary between crystal particles is minimized to improve ion transport, then ionic conductivity is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveionic conductivityVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex high-temperature sintering processes with a simple mixing and pressing method. Conductive carbon particles are mixed with oxide-based solid electrolyte particles and pressed to form the electrolyte layer, eliminating the need for complex grain boundary control while achieving high ionic conductivity through the conductive network.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 new solid electrolyte achieves high ion conductivity at room temperature, reducing internal resistance in electrochemical cells and improving overall battery performance and safety by ensuring uniform contact between the cathode and the electrolyte.

Implementation Method 1

mechanochemically mixing of the mixture to prepare the solid electrolyte

Methodology Applied

Scientific EffectMechanochemical mixing:

Implementation Method 2

it is desired for the solid electrolyte to have high ionic conductivity

Methodology Applied

Scientific EffectIonic conductivity: Conduction (electrical)

Data Source

PatentUS12206066B2Solid electrolyte, preparation method thereof, and electrochemical device including the same

Publication Date: 2025.01.21 SAMSUNG ELECTRONICS CO LTD

AI summary

A solid electrolyte includes: a crystalline composite, wherein the composite is a compound represented by Formula 1, a compound represented by Formula 2, or a combination thereof:3LiF-M12O3 Formula 1wherein, in Formula 1, M1 is an element having an oxidation number of +3, or a combination thereof, with the proviso that M1 is not aluminum or yttrium,3LiF-M2(OH)3 Formula 2wherein, in Formula 2, M2 is an element having an oxidation number of +3, or a combination thereof, with the proviso that M2 is not aluminum or yttrium.