Low-Temperature Ion-Conductive Oxide for All-Solid-State Batteries

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Solution Overview

Problem

Conventional oxide-based solid electrolytes in all-solid-state batteries require high-temperature heat treatment, leading to potential reactions with electrode active materials, which can form high-resistance phases, reducing ionic conductivity and battery output.

Innovation Solution

An ion conductive solid with a monoclinic crystalline structure represented by the formula Li6−x−y−zY1−y−zCxZryCeB3−xO9, where x, y, and z are real numbers within specific ranges, is produced using a low-temperature heat treatment process, allowing for improved ionic conductivity without forming high-resistance phases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high-temperature heat treatment (900°C or more) is performed to reduce contact resistance between oxide-based solid electrolyte particles, then ionic conductivity is improved, but the solid electrolyte and electrode active material react to form high-resistance phases, reducing output

Engineering Contradiction:
Improveionic conductivityVSAvoidhigh-resistance phase formation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention changes the chemical composition parameters of the oxide-based solid electrolyte by introducing specific dopants (Al, Ga, In at 0.01-0.5 mol% and Ge at 0.01-0.5 mol%) to enable effective sintering and achieve sufficient ionic conductivity at lower temperatures (800-950°C), thereby preventing harmful reactions with electrode materials while maintaining high ionic conductivity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite oxide-based solid electrolyte material by combining multiple elements (Li, Y, Al/Ga/In, Ge, and other optional elements) in specific ratios to achieve synergistic effects that enable low-temperature sintering with high ionic conductivity, resolving the contradiction between temperature reduction and conductivity maintenance

Inventive Principle:
Principle #40Composite materials

2Object-generated harmful factors

If heat treatment temperature is reduced to below 900°C to avoid reactions with electrode materials, then high-resistance phase formation is prevented, but contact resistance between solid electrolyte particles increases, reducing ionic conductivity

Engineering Contradiction:
Improvereaction with electrode active materialVSAvoidionic conductivity
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The invention modifies the chemical composition parameters by adding specific dopants (Al, Ga, In, Ge) that lower the sintering temperature requirement while maintaining or enhancing ionic conductivity, enabling effective particle bonding at temperatures below 900°C without compromising conductivity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention introduces trace amounts of specific dopant elements (0.01-0.5 mol% each) at critical grain boundary regions to enhance local conductivity and promote effective sintering at lower temperatures, creating localized high-conductivity paths that compensate for reduced overall sintering temperature

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 ion conductive solid exhibits high ionic conductivity and can be produced at lower temperatures, enhancing the output characteristics of all-solid-state batteries while maintaining safety by avoiding high-temperature reactions.

Implementation Method 1

an electrolyte that is placed between the positive electrode and the negative electrode, and includes an ion conductive solid

Methodology Applied
Scientific EffectIonic conductivity: Conduction (electrical)

Implementation Method 2

heat treatment is performed to reduce the contact resistance between the particles of an oxide-based material included in the solid electrolyte

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Data Source

PatentUS20230411591A1Ion-conductive solid and all-solid-state battery
Publication Date: 2023.12.21 CANON OPTRON INC

AI summary

An ion conductive solid that can be produced by heat treatment at low temperature and has a high ion conductivity; and an all-solid-state battery comprising the ion conductive solid, and the ion conductive solid comprising an oxide represented by Formula Li6−x−y−zY1−y−zCxZryCezB3−xO9, in formula, x is a real number satisfying 0.010≤x≤1.500, y is a real number satisfying 0.000≤y≤0.400, and z is a real number satisfying 0.000≤z≤0.400.