Nanofiber Oxide Coating for Conductive Corrosion-Resistant Electrode Plates
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Solution Overview
Problem
Existing coating systems for bipolar plates in fuel cells and electrolyzers lack long-term stability and high electrical conductivity while being cost-effective, and they do not provide adequate corrosion protection for metallic substrates.
Innovation Solution
A coating system comprising a base coat of titanium or titanium-niobium alloy, an intermediate coat of titanium niobium nitride or carbide, and a top coat of indium tin oxide nanofibers, which provides high electrical conductivity, corrosion protection, and mechanical protection, formed using PVD or CVD processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If noble metals are used for coating, then electrical conductivity is improved, but cost increases
Solution Approach 1:
The patent replaces expensive noble metals with cost-effective transparent conductive oxides (TCO) such as indium tin oxide (ITO), zinc oxide (ZnO), and tin oxide (SnO2). These materials provide comparable electrical conductivity at significantly lower cost, making the coating economically viable for large-scale bipolar plate production.
Solution Approach 2:
The patent optimizes the nanofiber morphology parameters (diameter, length, density, orientation) of the TCO top coat to maximize electrical conductivity. By controlling fiber dimensions and network structure through deposition parameters, the system achieves noble-metal-level conductivity without the associated cost.
2Reliability
If the coating system is made more complex to improve stability, then long-term stability is improved, but device complexity increases
Solution Approach 1:
The coating system is segmented into functionally distinct layers: base coat for corrosion protection, intermediate coats for property transition and adhesion, and top coat for conductivity. This segmentation provides long-term stability by ensuring each layer performs its specific function optimally while maintaining overall system reliability.
Solution Approach 2:
Intermediate coats consisting of metal nitrides, carbides, and carbonitrides serve as mediators between the metal oxide base coat and the TCO top coat. These intermediate layers provide gradual property transitions, ensuring good adhesion and electrical contact while maintaining long-term 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 coating system achieves high long-term stability, low costs, and excellent corrosion protection for metallic substrates, maintaining electrical conductivity and mechanical integrity under harsh conditions, comparable to noble metal coatings.
Implementation Method 1
The coating system is preferably formed using a PVD or a CVD process (PVD: physical vapor deposition; CVD: chemical vapor deposition)
Implementation Method 2
The coating system is preferably formed using a PVD or a CVD process (PVD: physical vapor deposition; CVD: chemical vapor deposition)
Implementation Method 3
The coating system is preferably formed using a PVD or a CVD process or a PACVD process (PACVD: plasma-assisted chemical vapor deposition)
Data Source
AI summary
A coating system for coating a metal substrate to form an electrode plate, comprising at least one top coat made of metal oxide, at least one intermediate coat carrying the top coat, and a base coat carrying the intermediate coat(s). The top coat is formed by a network of nanofibres either a) formed by indium tin oxide, which has optionally a third doping with at least one element from the group comprising carbon, nitrogen, boron, fluorine, hydrogen, phosphorus, sulphur, chlorine, bromine, aluminium, silicon, titanium, chromium, cobalt, nickel, copper, zircon, niobium, molybdenum, silver, antimony, hafnium, tantalum, tungsten or b) formed by doped tin oxide, wherein the tin oxide has at least one of the elements from the group comprising niobium, tantalum, antimony, fluorine as a fourth doping.