Silicate Oxyapatite Electrolyte for Low-Temperature Fuel Cells
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Solution Overview
Problem
Conventional solid state fuel cells using yttria-stabilized zirconia require high operating temperatures for effective ionic conductivity, and there is a need for a ceramic electrolyte that can achieve enhanced conductivity at lower temperatures.
Innovation Solution
A solid state fuel cell with a ceramic electrolyte composed of silicate oxyapatite doped with alkali metal cations, specifically represented by REy−xMxSi6O27±δ, where RE is a rare earth metal and M is an alkali metal, allowing for operation at relatively low temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If yttria-stabilized zirconia is used as ceramic electrolyte, then high ionic conductivity is achieved, but very high operating temperature (about 1000°C) is required
Solution Approach 1:
The patent changes the chemical composition parameters of the ceramic electrolyte by using silicate oxyapatite doped with alkali metal cations (M = Na, K, Rb, Cs) at specific concentrations (x = 0.5-2.0 in RE9.5-xMxSi6O27-δ), which fundamentally alters the ionic conduction mechanism and enables high conductivity at lower temperatures compared to conventional yttria-stabilized zirconia
Solution Approach 2:
The patent creates a composite ceramic electrolyte system combining rare earth metals (La, Nd, Sm, Gd, Dy, Er) with silicate oxyapatite structure and alkali metal dopants, forming a multi-component composite material that achieves synergistic effects for enhanced ionic conductivity at reduced operating temperatures
2Use of energy by stationary object
If operating temperature is reduced, then energy consumption is decreased, but ionic conductivity deteriorates
Solution Approach 1:
By changing the chemical composition parameters to silicate oxyapatite with alkali metal doping, the material exhibits peak ionic conductivity at lower temperatures (500-800°C), thereby reducing energy consumption while maintaining or improving ionic conductivity compared to conventional materials that require 1000°C operation
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 use of silicate oxyapatite doped with alkali metal cations enhances ionic conductivity at lower temperatures, enabling the solid state fuel cell to function effectively at temperatures ranging from 500°C to 800°C with improved electrical conductivity compared to conventional materials.
Implementation Method 1
the silicate oxyapatite may have an enhanced ionic conductivity at a relatively low temperature by doping with the alkali metal cations
Data Source
AI summary
A solid state fuel cell includes an anode, a cathode, and a ceramic electrolyte. The ceramic electrolyte includes a silicate oxyapatite represented by REy−xMxSiO6O27±δ, where RE is a rare earth metal, M is an alkali metal, x is greater than 0 and less than 2, y ranges from 9.3 to 10, and δ ranges from 0 to 2. A method for making the solid state fuel cell is also disclosed.