Perovskite Oxide Ionic Conductor Moisture Stability
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Solution Overview
Problem
Conventional ionic conductors, particularly perovskite oxides, lack stability in high humidity and thermal shock environments, leading to decomposition and reduced reliability in electrochemical devices like fuel cells and sensors.
Innovation Solution
A perovskite oxide ionic conductor with specific compositions represented by formulas BaZraCebM1cL1dO3-α, BaCexM2yL2zO3-α, and BaCeeInfL3gO3-α, incorporating elements like rare earth metals, indium, phosphorus, and boron/nitrogen, which enhance moisture resistance and reduction resistance by optimizing stoichiometric ratios and oxygen vacancies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional perovskite oxide ionic conductors (e.g., BaCe1-xMxO3) are used to achieve high ion conductivity, then conductivity is improved, but stability in high humidity and reducing atmosphere deteriorates
Solution Approach 1:
The patent employs composite material strategy by combining multiple elements (Ba, Zr, Ce, M1, L1) in a perovskite structure to achieve both high ion conductivity and enhanced stability. The specific composition BaZraCebM1cL1dO3-α integrates the conductivity benefits of Ce-based perovskites with the stability of Zr-based perovskites and additional stabilizing elements M1 and L1, resolving the contradiction between conductivity and moisture/reduction resistance
Solution Approach 2:
The patent applies parameter changes by precisely controlling the stoichiometric ratios (a, b, c, d) of constituent elements and the oxygen vacancy concentration (α) to optimize both conductivity and stability. By adjusting these compositional parameters within specific ranges, the material achieves a balance between high ion conductivity and resistance to moisture and reduction, directly addressing the technical contradiction
2Reliability
If SrCe1-xMxO3 or CaZr1-xMxO3 are used as proton conductors, then conductivity is achieved, but reliability in limited environments deteriorates due to decomposition in water and high humidity
Solution Approach 1:
The patent uses composite material approach by formulating BaZraCebM1cL1dO3-α that combines the advantages of different perovskite systems. The inclusion of Ba provides structural stability against moisture, while Zr and Ce contribute to proton conductivity, and M1/L1 elements further enhance both properties synergistically, achieving reliable proton conduction with improved environmental stability
Solution Approach 2:
The patent introduces intermediary elements M1 (from rare earth, In, Mn, Fe, Co, Ni, Al, or Ga groups) and L1 (from P, B, or N groups) that act as mediators to enhance the interaction between the perovskite structure and the operating environment. These intermediary elements improve the material's resistance to water and humidity while maintaining proton conductivity, resolving the stability issue of conventional proton conductors
3Stability of the object's composition
If BaZr1-x-yCexMyO3 is used to improve stability in boiling water, then moisture resistance is improved, but ion conductivity deteriorates due to low conductivity compared to BaCe1-xMxO3
Solution Approach 1:
The patent applies composite material strategy by creating BaZraCebM1cL1dO3-α that merges the moisture stability of BaZr-based perovskites with the high conductivity characteristics of BaCe-based perovskites. The dual substitution approach (M1 at A-site, L1 at B-site) creates a composite structure that simultaneously achieves boiling water stability and high ion conductivity, overcoming the limitations of single-element substitution
4Temperature
If ionic conductors are designed for high temperature operation, then thermal conductivity is improved, but resistance to thermal shock and reduction deteriorates
Solution Approach 1:
The patent uses parameter changes by optimizing the compositional parameters (a, b, c, d ratios and oxygen vacancy α) to achieve a perovskite structure that maintains structural integrity at high temperatures while resisting thermal shock and reduction. The specific stoichiometric control creates a material that can operate at elevated temperatures without decomposing or suffering from thermal stress, resolving the contradiction between temperature capability and stability
Data Source
AI summary
A material which conducts protons or oxide ions with high ionic conductivity and is excellent in moisture resistance and reduction resistance is provided. A perovskite oxide represented by the formula (1):BaZraCebM1cL1dO3-α (1)(wherein M1 is at least one member selected from the group consisting of rare earth elements, In, Mn, Fe, Co, Ni, Al and Ga, L1 is at least one member selected from the group consisting of P, B and N and a, b, c, d and a satisfy 0≦a<1.2, 0<b<1.2, 0<c<1.2, 0.9<a+b+c<1.2, 0<d<0.1 and 0<α<3) is used as an ionic conductor.