Antimony-Doped Tin Oxide Fuel Cell Separator Coating
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Solution Overview
Problem
Existing fuel cell separators face challenges in achieving high corrosion resistance and electrical conductivity while maintaining low manufacturing costs and productivity, as noble metal coating methods are costly and carbon-containing coating films have low productivity.
Innovation Solution
A fuel cell separator is developed using an antimony-doped tin oxide film with an alkyl group substituted with at least one fluorine atom, where the fluorine to tin element ratio is between 3 and 7, formed by mixing alkyl acid, tin chloride, and antimony chloride, and deposited onto a substrate using aerosol deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a noble metal plating film is formed on the separator substrate, then corrosion resistance is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive noble metal plating films with a cost-effective tin oxide-based coating that provides comparable corrosion resistance. The coating uses inexpensive materials (tin chloride, antimony chloride, fluorinated alkyl acid) and can be applied through simple dip-coating or spray methods, eliminating the need for costly noble metal deposits while maintaining protective functionality against hydrofluoric acid corrosion.
Solution Approach 2:
The patent modifies the chemical composition parameters of the coating by incorporating fluorinated alkyl groups into the tin oxide structure. This parameter change (adding fluorine atoms with specific F/Sn ratios between 0.5-2.0) enhances the coating's corrosion resistance and hydrophobicity, providing noble metal-level protection through compositional modification rather than expensive material substitution.
2Reliability
If a carbon-containing coating film is formed on the noble metal coating film, then electrical conductivity is improved, but productivity decreases
Solution Approach 1:
The patent combines the corrosion protection function and electrical conductivity function into a single integrated coating layer. The tin oxide-based coating inherently provides both corrosion resistance and sufficient electrical conductivity for fuel cell separators, eliminating the need for separate noble metal and carbon coating steps. This merger of functions into one coating process significantly improves manufacturing productivity while maintaining performance.
Solution Approach 2:
The patent extracts and eliminates the intermediate noble metal plating step from the traditional multi-layer coating process. By using tin oxide as the base coating material, the patent achieves both corrosion protection and electrical conductivity in one layer, removing the need for subsequent carbon-containing coating steps and simplifying the overall manufacturing process.
3Productivity
If the separator surface is made hydrophilic, then water transport is improved, but acid permeability increases
Solution Approach 1:
The patent applies local quality modification by creating a coating with specific fluorinated regions that provide hydrophobicity where needed. The fluorinated alkyl groups create localized hydrophobic zones on the coating surface that repel acid while allowing controlled water transport through the porous structure, achieving spatial differentiation of properties within the same coating layer.
Solution Approach 2:
The patent creates a composite coating structure combining tin oxide particles with fluorinated alkyl groups. This composite material integrates the porous structure of tin oxide (for water transport) with the hydrophobic properties of fluorinated groups (for acid resistance), achieving both water transport efficiency and corrosion protection simultaneously through material composition rather than surface hydrophilicity.
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 provides a fuel cell separator with enhanced corrosion resistance and electrical conductivity, as demonstrated by improved water repellency and reduced acid permeability, maintaining high performance even under severe acidic conditions.
Implementation Method 1
spraying the particles onto the substrate and forming a film by aerosol deposition
Data Source
AI summary
A fuel cell separator having high corrosion resistance and electrical conductivity is provided. This fuel cell separator includes, on a substrate, an antimony-doped tin oxide film having an alkyl group substituted with at least one fluorine atom, in which an element ratio of fluorine to tin (F/Sn) in the film is 3 or more and 7 or less.