Solid-Oxide Secondary Cell Electrodes for Low-Temperature Operation

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Solution Overview

Problem

Existing secondary cells, particularly lithium-ion and lithium-air batteries, face environmental and health hazards due to the use of critical raw materials like lithium, and safety risks from flammable liquid electrolytes, with operating temperatures unsuitable for consumer electronics and portable applications.

Innovation Solution

A secondary cell design utilizing a solid electrolyte for oxygen ion conduction with mixed ionic and electronic structures based on ABO3 and CeMO2 crystal structures, operating at low temperatures below 400°C, eliminating the need for lithium and reducing safety risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If lithium-ion rechargeable batteries use liquid electrolytes, then ion conduction is achieved, but safety risks increase due to flammability

Engineering Contradiction:
ImprovesafetyVSAvoidflammability
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the physical state parameter of the electrolyte from liquid to solid, eliminating flammability while maintaining ion conduction capability. The solid electrolyte comprises a ceramic material with oxygen vacancies that enable lithium ion transport without the safety hazards of liquid electrolytes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces expensive and hazardous lithium cobalt oxide with cheaper and safer iron-based cathode materials, reducing both cost and environmental impact while maintaining battery functionality through the solid electrolyte interface.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Use of energy by moving object

If lithium cobalt oxide is used in the positive electrode, then high energy density is achieved, but environmental and health hazards increase

Engineering Contradiction:
Improveenergy densityVSAvoidenvironmental hazards
Core Design Contradiction:
Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent substitutes expensive and hazardous lithium cobalt oxide with cheaper, abundant iron-based cathode materials, reducing both cost and environmental impact. The iron-based material provides sufficient energy density for the application while eliminating cobalt's toxicological and environmental concerns.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the chemical composition parameter of the cathode from lithium cobalt oxide to iron-based materials, fundamentally altering the material's environmental profile while maintaining electrochemical functionality through the solid electrolyte interface.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If all-solid-state lithium batteries use solid electrolyte, then safety is improved, but critical raw materials like lithium are still intensively used

Engineering Contradiction:
ImprovesafetyVSAvoidlithium consumption
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent replaces expensive and critical lithium cobalt oxide with cheaper, abundant iron-based cathode materials, reducing dependence on critical raw materials. The solid electrolyte enables this substitution by providing a stable interface that accommodates the different electrochemical properties of iron-based materials.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the chemical composition parameter of the cathode from lithium-intensive materials to iron-based materials with reduced lithium content, fundamentally altering the battery's raw material profile while maintaining functionality through the solid electrolyte.

Inventive Principle:
Principle #35Parameter changes

4Use of energy by moving object

If secondary cells operate at temperatures above 500°C, then ion conduction is enhanced, but corrosion of cell elements increases

Engineering Contradiction:
Improveion conductionVSAvoidcorrosion
Core Design Contradiction:
Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent changes the operating temperature parameter from high temperature (>500°C) to low temperature (below 400°C), reducing thermal stress and corrosion while maintaining sufficient ion conduction through the solid electrolyte's oxygen vacancy mechanism.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses cheaper and more stable iron-based cathode materials that can operate at lower temperatures without degradation, replacing expensive high-temperature materials and reducing overall system cost and complexity.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 design achieves safe, lithium-free operation at low temperatures, enhancing safety and reducing environmental hazards while enabling efficient oxygen ion conduction suitable for consumer electronics and portable applications.

Implementation Method 1

a solid electrolyte to conduct oxygen ions

Methodology Applied
Scientific EffectOxygen ion conduction: Conduction (electrical)

Implementation Method 2

The mixed ionic and electronic structure comprises an ABO3 structure... and/or a CeMO2 structure... for conducting oxygen ions and electrons

Methodology Applied
Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 3

A lithium-ion rechargeable battery is configured to generate electric energy through redox reactions occurring during lithium-ion intercalation / deintercalation

Methodology Applied
Scientific EffectRedox reactions: Redox Reactions

Data Source

PatentEP4519929B1Secondary cells
Publication Date: 2026.03.11 VIENNA UNIVERSITY OF TECHNOLOGY
  • EP4519929B1 patent drawingFigure 1
  • EP4519929B1 patent drawingFigure 2~3
  • EP4519929B1 patent drawingFigure 4

AI summary

A secondary cell is provided. The secondary cell comprises a solid electrolyte to conduct oxygen ions, a positive electrode configured to be in contact with the solid electrolyte, and a negative electrode configured to be in contact with the solid electrolyte. The positive and the negative electrode comprise a mixed ionic and electronic structure for conducting oxygen ions and electrons. The mixed ionic and electronic structure comprises an ABO3 structure, wherein the A site corresponds to a first chemical element with a first covalent radius, wherein the B site corresponds to a second chemical element with a second covalent radius; and / or a CeMO2 structure, wherein the Ce is Cerium and M is a metal.