Perovskite Oxide Cathodes for Intermediate Temperature SOFCs

Solution Overview

Problem

Current solid oxide fuel cells (SOFCs) and ion transport membranes (ITMs) operate at high temperatures, leading to high costs and reliability issues due to thermal cycling and material inter-diffusion, necessitating the development of materials for intermediate temperature operation to reduce costs and enhance performance.

Innovation Solution

Development of perovskite oxide compositions with specific formulas (ABO3)p(A′BO2+x)q(A′O2+x)r and (AB′O3)p(A′B′O2+x)q(A′O2+x)r, which exhibit enhanced oxygen ion diffusivity and conductivity, suitable for use as cathodes and electrolytes in intermediate temperature SOFCs and ITMs, allowing operation between 400° C. and 800° C.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high temperature operation is used in SOFCs and ITMs, then sufficient ion transport and electrocatalysis are achieved, but operating costs increase and reliability decreases due to thermal cycling and material inter-diffusion

Engineering Contradiction:

Improvesystem reliabilityVSAvoidoperating temperature

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The patent changes the chemical composition parameters of the electrolyte and electrode materials by incorporating specific dopants (ceria, gadolinia, lanthanum strontium manganite) to enable intermediate temperature operation. This compositional modification allows the system to maintain sufficient ionic conductivity and electrocatalytic activity at lower temperatures (500-800°C) while improving reliability by reducing thermal stress and material degradation

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material structures combining multiple oxide phases (ceria-gadolinia, lanthanum strontium manganite, nickel-YSZ cermet) to achieve both intermediate temperature operation and high performance. The composite nature allows synergistic effects where different materials contribute specific properties: ceria-gadolinia provides ionic conductivity, lanthanum strontium manganite provides electrocatalysis, and nickel-YSZ cermet provides fuel oxidation capability

Inventive Principle:

Principle #40Composite materials

2Productivity

If high temperature operation is used in SOFCs and ITMs, then adequate oxygen ion transport and electrocatalysis are achieved, but material degradation and inter-diffusion occur

Engineering Contradiction:

Improveion transport efficiencyVSAvoidmaterial stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The patent modifies the chemical composition parameters by incorporating stabilizing dopants (yttria in zirconia, ceria-gadolinia mixtures) that maintain material stability at operating temperatures. These compositional changes prevent excessive ion migration and phase decomposition while preserving adequate ionic conductivity for high productivity

Inventive Principle:

Principle #35Parameter changes

3Reliability

If intermediate temperature operation is implemented, then operating costs are reduced and reliability is improved, but new material combinations are required to achieve sufficient ion transport and electrocatalysis

Engineering Contradiction:

Improvesystem reliabilityVSAvoidmaterial compatibility

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs composite material structures combining multiple oxide phases (ceria-gadolinia, lanthanum strontium manganite, nickel-YSZ cermet) to achieve both intermediate temperature operation and high performance. The composite nature allows synergistic effects where different materials contribute specific properties: ceria-gadolinia provides ionic conductivity, lanthanum strontium manganite provides electrocatalysis, and nickel-YSZ cermet provides fuel oxidation capability

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the chemical composition parameters of the electrolyte and electrode materials by incorporating specific dopants (ceria, gadolinia, lanthanum strontium manganite) to enable intermediate temperature operation. This compositional modification allows the system to maintain sufficient ionic conductivity and electrocatalytic activity at lower temperatures (500-800°C) while improving reliability by reducing thermal stress and material degradation

Inventive Principle:

Principle #35Parameter changes

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

These compositions enable efficient oxygen reduction and separation, reducing operating costs and improving the reliability and performance of SOFCs and ITMs by allowing operation at lower temperatures, thus overcoming the limitations of high-temperature systems.

Implementation Method 1

the cathode compositions possess both oxygen ion diffusivity and electronic conductivity

Methodology Applied

Scientific EffectIon diffusion: Diffusion

Implementation Method 2

the electrolyte compositions is a pure ionic conductor

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 3

efficient electrocatalysis of the oxygen reduction and fuel oxidation reactions

Methodology Applied

Scientific EffectElectrochemical reduction: Fuel Cell

Data Source

PatentUS8637209B2Cathode and electrolyte materials for solid oxide fuel cells and ion transport membranes

Publication Date: 2014.01.28 JACOBSON ALLAN J

AI summary

Novel cathode, electrolyte and oxygen separation materials are disclosed that operate at intermediate temperatures for use in solid oxide fuel cells and ion transport membranes based on oxides with perovskite related structures and an ordered arrangement of A site cations. The materials have significantly faster oxygen kinetics than in corresponding disordered perovskites.