Solid Oxide Fuel Cell Oxygen Ion Blocking Layer
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Solution Overview
Problem
In solid-oxide proton conduction type fuel cells, the conduction of oxygen ions in the solid electrolyte layer leads to water generation, which decreases the electromotive force if not quickly removed, and existing solutions fail to effectively suppress oxygen ion conduction in doped zirconia and ceria-based electrolytes.
Innovation Solution
A fuel cell design incorporating a cathode electrode, an anode electrode, and a solid electrolyte layer formed from doped polycrystalline zirconia or ceria, with a first oxygen ion blocking layer having lower oxygen ion conductivity than the solid electrolyte layer, preventing oxygen ions from diffusing into the electrolyte and thus suppressing water generation within the electrolyte.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If doped zirconia or ceria is used as solid electrolyte layer to enable proton conduction, then power generation efficiency is improved, but oxygen ion conduction occurs leading to water generation and electromotive force decrease
Solution Approach 1:
An oxygen ion blocking layer is introduced as an intermediary between the cathode electrode and the solid electrolyte layer. This intermediate layer selectively blocks oxygen ions from entering the electrolyte while allowing protons to pass through, thereby preventing water generation in the electrolyte without affecting the proton conduction function of the doped zirconia or ceria electrolyte.
2Productivity
If solid electrolyte layer is thinned to improve ionic conductivity, then power generation efficiency increases, but oxygen ion conduction becomes more significant causing water generation
Solution Approach 1:
The oxygen ion blocking layer serves as a mediator that allows the solid electrolyte layer to be thinned for improved ionic conductivity while preventing the harmful effect of oxygen ion conduction. The blocking layer compensates for the increased oxygen ion permeability that would otherwise result from thinning the electrolyte.
3Temperature
If doped zirconia or ceria is used for low temperature operation, then operating temperature is reduced, but oxygen ion conduction increases leading to water retention and electromotive force decrease
Solution Approach 1:
The oxygen ion blocking layer enables low temperature operation by preventing oxygen ion conduction that would otherwise be significant at lower temperatures. This allows the fuel cell to operate efficiently at reduced temperatures without suffering from water generation and retention in the electrolyte layer.
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 configuration enhances power generation efficiency and allows operation at low temperatures by preventing water retention in the solid electrolyte, maintaining high electromotive force and mechanical strength.
Implementation Method 1
a proton generated from a fuel gas in contact with an anode electrode is conducted in an electrolyte composed of solid oxide
Implementation Method 2
a first oxygen ion blocking layer having lower oxygen ion conductivity than the solid electrolyte layer, between the cathode electrode and the solid electrolyte layer
Data Source
AI summary
Provided is a solid oxide fuel cell having high power generation efficiency and being operable at low temperature. A fuel cell of the present invention includes a cathode electrode, an anode electrode, and a solid electrolyte layer disposed between the cathode electrode and the anode electrode and formed from polycrystalline zirconia or polycrystalline ceria doped with divalent or trivalent positive ions and having proton conductivity, in which the cathode electrode and the solid electrolyte layer are stacked with a first oxygen ion blocking layer interposed therebetween.