Solid Ionic Electrolytes to Prevent Fuel Cell Cross-Diffusion
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Solution Overview
Problem
Existing electrochemical devices face challenges with poor durability and high cost due to the use of materials like Nafion® membranes, which are not stable and allow cross-diffusion of chemicals and gases, leading to efficiency loss and safety issues.
Innovation Solution
Development of solid ionic conducting materials, such as oxyhydroxides and hydrated oxides with perovskite, Brownmillerite, or K4CdCl6 structures, which are derived from specific ceramic oxides, offering improved durability and reduced cost by minimizing cross-diffusion and enhancing mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Nafion® membrane is used as electrolyte, then good proton conduction is achieved, but stability deteriorates due to oxidation by H2O2 and Pt electrode diffusion
Solution Approach 1:
The patent changes the chemical composition and physical state of the electrolyte from a polymeric membrane (Nafion®) to an inorganic solid electrolyte with specific crystal structures (perovskite, Brownmillerite, K4CdCl6). This parameter change transforms the material from organic to inorganic, providing resistance against oxidation by H2O2 and preventing Pt electrode diffusion, thereby resolving the stability and lifetime issues.
Solution Approach 2:
The patent employs composite material strategies by combining inorganic solid electrolyte materials with specific crystal structures. These composite inorganic materials integrate multiple functional properties: high proton conductivity, chemical stability against oxidation, and resistance to electrode material diffusion, simultaneously addressing the limitations of conventional polymeric membranes.
2Stability of the object's composition
If polymeric Nafion® membrane is used, then flexibility is maintained, but density deteriorates allowing H2 cross-diffusion
Solution Approach 1:
The patent changes the physical state and density parameters by transitioning from a polymeric membrane to a dense inorganic solid electrolyte. The inorganic materials with perovskite, Brownmillerite, or K4CdCl6 structures provide higher density and tighter atomic packing, which physically blocks hydrogen cross-diffusion while maintaining proton conduction pathways through defect mechanisms.
3Reliability
If liquid KOH solution electrolyte is used in alkaline fuel cells, then OH− conduction is achieved, but stability deteriorates
Solution Approach 1:
The patent applies phase transition by converting the electrolyte from liquid phase (KOH solution) to solid phase (inorganic solid electrolyte with specific crystal structures). This phase change eliminates the stability issues associated with liquid electrolytes while enabling the use of air without CO2 removal, thereby reducing operating costs and improving overall system stability.
4Ease of manufacture
If lower cost membranes are sought to replace Nafion®, then cost is reduced, but performance may deteriorate
Solution Approach 1:
The patent changes the material composition parameters from expensive polymeric Nafion® to cost-effective inorganic materials with specific crystal structures. The inorganic solid electrolytes based on perovskite, Brownmillerite, or K4CdCl6 structures provide comparable or superior performance at lower cost, achieving both economic and technical objectives simultaneously.
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 new materials extend the lifetime of hydrogen fuel cells to 20000 hours, reduce costs, and enhance efficiency by preventing cross-diffusion, making them more competitive with battery technologies and suitable for large-scale applications.
Implementation Method 1
Ionic conducting materials are used, e.g. as electrolytes, in electrochemical devices such as fuel cells, electrolysers, batteries
Implementation Method 2
Development of robust and low-cost solid ionic conducting materials would allow the durability to be improved
Data Source
AI summary
A solid ionic conducting material for use in an electrochemical device comprises an oxyhydroxide or hydrated oxide derived from of an oxide with a perovskite, Brownmillerite, layered oxide, and/or K4CdCl6 structure, the elemental composition of the initial oxide being selected to provide suitable conduction properties for the derived anhydrous or hydrated oxyhydroxide or hydrated oxide. A method of making such a solid ionic conducting material, including treatment with water, and an electrochemical device incorporating such a solid ionic conducting material (optionally as an electrolyte) are also disclosed.