Solid Oxide Cell Oxygen Electrode Composition to Suppress SrZrO3

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Solution Overview

Problem

Solid oxide electrochemical cells face challenges with the formation of high-resistance layers at interfaces, particularly due to the formation of SrZrO3, which hampers electrochemical performance despite the introduction of ceria-based interlayers.

Innovation Solution

Incorporating a strontium-containing perovskite-type composite oxide with tetravalent elements like Ti or Ce into the oxygen electrode material, which inhibits the diffusion of Sr during heating, thereby reducing the formation of SrZrO3 at the electrolyte interface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a ceria-based interlayer is introduced at the interface between the oxygen electrode and the electrolyte, then the formation of SrZrO3 at the electrode-electrolyte interface is prevented, but SrZrO3 with high resistance is still formed at the interface between the interlayer and the electrolyte

Engineering Contradiction:

Improveinterface stabilityVSAvoidhigh-resistance layer formation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the chemical composition parameters of the oxygen electrode material by incorporating specific elements (Ti, Zr, or Ce) at controlled concentrations (0.01-0.30 atomic ratio) into the perovskite structure. This compositional modification alters the diffusion behavior of Sr during heating, preventing Sr from reaching the interlayer-electrolyte interface and forming high-resistance SrZrO3, while maintaining the protective function of the ceria-based interlayer.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite oxygen electrode material by combining strontium-containing perovskite-type composite oxide with specific elements (Ti, Zr, or Ce). This composite structure leverages the high reactivity of these elements with Sr to inhibit Sr diffusion, while the perovskite structure maintains electrochemical performance. The multi-layer structure (oxygen electrode + ceria-based interlayer + YSZ electrolyte) also represents a composite material approach to solving the interface resistance problem.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If Sr diffusion is allowed during heating, then the sintering and formation process is simplified, but Sr reacts with Zr to form SrZrO3 with high resistance at the YSZ interface

Engineering Contradiction:

Improveheating process simplicityVSAvoidSrZrO3 formation

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The invention applies preliminary anti-action by incorporating elements (Ti, Zr, or Ce) into the oxygen electrode material before the heating process. These elements are positioned in advance to intercept and react with Sr during heating, preventing Sr from reaching the YSZ electrolyte and forming harmful SrZrO3. This preliminary preparation allows the heating process to proceed without special restrictions while still preventing the harmful reaction.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The elements Ti, Zr, or Ce act as intermediary substances between Sr and the YSZ electrolyte. During heating, these intermediaries preferentially react with Sr or form barriers that prevent Sr diffusion to the electrolyte interface. This intermediary mechanism allows simplified heating processes while preventing SrZrO3 formation, as the intermediaries absorb the harmful interaction between Sr and Zr.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

This approach effectively inhibits the formation of high-resistance phases, enhancing the electrochemical performance and efficiency of both solid oxide fuel cells and electrolysis cells by reducing thermal diffusion of Sr, leading to improved power generation and electrolysis efficiency.

Implementation Method 1

Sr diffuses through an interlayer from an oxygen electrode, reaches the interface with YSZ, which is a solid electrolyte, and Sr reacts with Zr which has high reactivity with Sr to form SrZrO3

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 2

Sr reacts with Zr which has high reactivity with Sr to form SrZrO3. The present inventors have focused on Ti which has higher reactivity with Sr than Zr

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 3

Solid oxide electrochemical cells include solid oxide electrolysis cells (SOEC) and solid oxide fuel cells (SOFC)

Methodology Applied

Scientific EffectElectrochemical reaction: Electrolysis

Data Source

PatentUS20230282840A1Solid oxide electrochemical cell and use thereof

Publication Date: 2023.09.07 JAPAN FINE CERAMICS CENTER

AI summary

A solid oxide electrochemical cell includes an oxygen electrode containing a strontium-containing perovskite-type composite oxide represented by Ln1-xSrxCo1-y-zFeyBzO3-δ (Ln is a trivalent lanthanide element, B is a tetravalent element, 0<x<1, 0≤y<1, 0<z<1, and 0<z+y<1, and δ is a value that is determined to satisfy charge neutrality conditions), a solid electrolyte containing zirconium oxide, a hydrogen electrode, and an interlayer containing a rare-earth-doped cerium oxide that is provided between the solid electrolyte and the oxygen electrode.