SOEC Air-Side Electrode Barrier Layer Design

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Solution Overview

Problem

Solid oxide electrolyzer cells face air-side electrode degradation due to cell voltage increases during the electrolysis process, leading to delamination issues at high current densities.

Innovation Solution

Incorporating a barrier layer with stabilized zirconia material of lower electrical conductivity than the electrolyte, combined with a functional layer, to mitigate over-potential and prevent delamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a conventional air-side electrode is used in solid oxide electrolyzer cells, then the cell can operate in electrolysis mode, but the air-side electrode degrades due to cell voltage increases during electrolysis

Engineering Contradiction:

Improveelectrolysis operationVSAvoidair-side electrode stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The air-side electrode is segmented into multiple functional layers: a barrier layer containing stabilized zirconia material with lower electrical conductivity, and a functional layer with higher electrical conductivity. This segmentation allows different regions of the electrode to perform different functions - the barrier layer mitigates over-potential while the functional layer maintains electrochemical activity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the air-side electrode are given different electrical conductivity properties. The barrier layer has lower electrical conductivity to reduce over-potential, while the functional layer has higher electrical conductivity to maintain electrochemical performance. This local differentiation of properties resolves the contradiction between stability and productivity.

Inventive Principle:

Principle #3Local quality

2Productivity

If high current density is applied during electrolysis, then hydrogen production efficiency increases, but air-side electrode delamination occurs

Engineering Contradiction:

Improvehydrogen production efficiencyVSAvoidelectrode adhesion

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The barrier layer is incorporated into the air-side electrode structure before electrolysis operation begins. This layer acts as a cushioning element that prevents over-potential buildup and reduces stress at the electrode-electrolyte interface, thereby preventing delamination even when high current densities are applied during operation.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Power

If the air-side electrode material has high electrical conductivity, then electrochemical performance is improved, but cell voltage over-potential increases

Engineering Contradiction:

Improveelectrochemical performanceVSAvoidcell voltage over-potential

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

The air-side electrode uses local quality differentiation with a barrier layer of lower electrical conductivity to reduce over-potential and a functional layer of higher electrical conductivity to maintain electrochemical performance. This spatial variation in electrical properties resolves the contradiction between power and energy loss.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The air-side electrode is constructed as a composite material system combining stabilized zirconia barrier layer with functional layer materials. This composite structure integrates the beneficial properties of different materials - the barrier layer's low conductivity for reduced over-potential and the functional layer's high conductivity for improved electrochemical performance.

Inventive Principle:

Principle #40Composite materials

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 solution effectively reduces cell voltage over-potential and prevents air-side electrode delamination during electrolysis, enhancing the stability and longevity of the electrolyzer cells.

Implementation Method 1

The air-side electrode includes a barrier layer disposed on the air side of the electrolyte and containing a stabilized zirconia material having a lower electrical conductivity than an electrical conductivity of the electrolyte

Methodology Applied

Scientific EffectElectrical conductivity: Conduction (electrical)

Data Source

PatentUS20220190373A1Solid oxide electrolyzer cell including electrolysis-tolerant air-side electrode

Publication Date: 2022.06.16 BLOOM ENERGY CORP

AI summary

A solid oxide electrolyzer cell (SOEC) includes a solid oxide electrolyte, a fuel-side electrode disposed on a fuel side of the electrolyte, and an air-side electrode disposed on an air side of the electrolyte. The air-side electrode includes a barrier layer disposed on the air side of the electrolyte and containing a stabilized zirconia material having a lower electrical conductivity than an electrical conductivity of the electrolyte, and a functional layer disposed on the barrier layer.