Titanium Suboxide Fuel Cell Electrode Corrosion Resistance
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Solution Overview
Problem
Carbon-based electrically conductive materials used in fuel cells are prone to corrosion due to oxidation reactions at high potentials and acidic environments, and alternative materials with high resistance and conductivity have not been effectively found.
Innovation Solution
Development of a titanium suboxide particulate powder with a rutile crystalline phase and specific oxygen vacancy distribution, produced by firing titanium oxide in a reducing atmosphere followed by an ammonia treatment, which maintains high electrical conductivity under severe conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon is used as an electrically conductive material, then high electrical conductivity is achieved, but corrosion occurs due to oxidation reaction at high potential
Solution Approach 1:
The invention changes the chemical composition parameters by using titanium suboxide (TiOx where 1.5 ≤ x < 2.0) instead of carbon, and controls the oxygen vacancy concentration and surface oxygen content to achieve both high electrical conductivity and oxidation resistance. The specific compositional range and surface treatment parameters resolve the contradiction between conductivity and corrosion resistance.
Solution Approach 2:
The invention creates a composite structure with titanium suboxide particles having specific surface area (5-200 m²/g) and controlled surface oxygen content (10-50 at%). This composite approach combines the high conductivity of metallic-like titanium suboxide with surface oxidation resistance, resolving the contradiction between conductivity and corrosion resistance.
2Reliability
If titanium suboxide with high surface area is used to increase conductivity, then electrical conductivity improves, but surface re-oxidation reduces oxygen vacancies and lowers conductivity
Solution Approach 1:
The invention applies local quality control by maintaining high oxygen vacancy concentration in the bulk of titanium suboxide particles while allowing controlled surface oxygen content (10-50 at%). This local differentiation preserves bulk conductivity through oxygen vacancies while providing surface oxidation resistance, resolving the contradiction between conductivity and surface stability.
Solution Approach 2:
The invention performs preliminary surface treatment during the firing process to control surface oxygen content before the material is put into service. By pre-establishing the surface oxygen content in the range of 10-50 at% during manufacturing, the material is prepared in advance to resist re-oxidation and maintain conductivity during use.
3Reliability
If titanium oxide is fired in reducing atmosphere to create oxygen vacancies, then electrical conductivity increases, but crystal structure stability decreases under severe conditions
Solution Approach 1:
The invention changes the firing parameters by controlling the oxygen partial pressure and temperature to achieve a specific oxygen vacancy concentration that maintains rutile crystal structure stability. By optimizing these parameters, the material achieves high electrical conductivity while preserving structural stability under severe operating conditions.
Solution Approach 2:
The invention utilizes phase transition control by maintaining the rutile crystal structure during the firing process in reducing atmosphere. By controlling the phase transition behavior and preventing transformation to less stable phases, the material achieves both high conductivity through oxygen vacancies and structural stability under operating conditions.
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 resulting material provides excellent resistance to high potentials and acidic environments, offering high electrical conductivity suitable for fuel cells and other applications, and can be easily and industrially produced.
Implementation Method 1
firing a raw material containing a titanium oxide having a specific surface area of 20 m2/g or greater in a reducing atmosphere
Implementation Method 2
oxidation reaction of carbon (C+2H2O→CO2+4H++4e−) of a catalyst for electrodes
Data Source
AI summary
The present invention provides an electrically conductive material having excellent resistance to a high potential and strongly acidic environment and high electrical conductivity; and an electrode material and a fuel cell each including the same. The present invention also provides a method for simply and easily producing such an electrically conductive material. The present invention relates to an electrically conductive material including a titanium suboxide particulate powder, the titanium suboxide particulate powder including a rutile crystalline phase as a main phase, and having a composition of TiOn wherein n is 1.5 or more and 1.90 or less, and a brightness L* in the L*a*b*color system of 35 to 45.