Bifunctional Air Electrode with Titanium Suboxide Layer
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Solution Overview
Problem
Bifunctional air electrodes in metal-air batteries face challenges in maintaining high electrical conductivity and corrosion resistance, especially in aqueous chloride environments, which affects their performance and longevity.
Innovation Solution
A bifunctional air electrode with a titanium current collector and a conductive titanium suboxide layer, combined with a corrosion-resistant outer layer, is used to enhance electrical conductivity and corrosion resistance, while a hydrophobic membrane ensures air permeability and prevents electrolyte flooding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-layer current collector is used, then the structure is simple, but it cannot simultaneously achieve high corrosion resistance and high electrical conductivity
Solution Approach 1:
The current collector is constructed as a composite structure with an inner layer of highly conductive material (e.g., copper or aluminum) and an outer layer of corrosion-resistant material (e.g., titanium or stainless steel). This composite design allows the inner layer to provide high electrical conductivity while the outer layer provides corrosion resistance in aqueous chloride environments, resolving the contradiction between simplicity and dual-performance requirements.
2Duration of action of stationary object
If the outer layer has higher corrosion resistance, then longevity is improved, but electrical conductivity decreases
Solution Approach 1:
Different layers of the current collector are assigned different functional properties: the inner layer is optimized for electrical conductivity with materials like copper or aluminum, while the outer layer is optimized for corrosion resistance with materials like titanium or stainless steel. This local differentiation of material properties allows each layer to excel at its specific function, resolving the contradiction between longevity and conductivity.
3Productivity
If the air electrode is made porous for gas diffusion, then oxygen permeability is improved, but mechanical strength decreases
Solution Approach 1:
The air electrode incorporates a porous structure with controlled pore sizes and distributions to facilitate oxygen gas diffusion from the ambient air to the reaction sites. The porous morphology increases the surface area and mass transport efficiency, improving oxygen permeability while the overall composite structure maintains adequate mechanical strength through the layered architecture.
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 improves the electrical conductivity and corrosion resistance of the air electrode, maintaining performance and longevity, even under anodic potentials in chloride environments, and ensures efficient oxygen reduction and evolution reactions.
Implementation Method 1
the corrosion-resistant outer layer has a greater corrosion resistance than the conductive inner layer
Implementation Method 2
the conductive inner layer has a higher level of electrical conductivity than the corrosion-resistant outer layer
Implementation Method 3
an air permeable, hydrophobic membrane
Implementation Method 4
when acting as a cathode and accepting electrons from an outside source, it allows oxygen to be reduced to hydroxide ions
Implementation Method 5
When acting as an anode, and electrons are delivered to external circuits, it oxidizes hydroxide ion in water to oxygen gas
Data Source
AI summary
Performance, properties and stability of bifunctional air electrodes may be improved by using modified current collectors, and improving water wettability of air electrode structures. This invention provides information on creating non-corroding, electrically rechargeable, bifunctional air electrodes. In some embodiments, this bifunctional air electrode includes a corrosion-resistant outer layer and an electrically conductive inner layer. In some embodiments, this bifunctional air electrode includes titanium suboxides formed by reducing titanium dioxide. Titanium suboxides may be corrosion-resistant and electrically conductive.