Porous Current Collector with Tin Alloy and Silver Layer
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Solution Overview
Problem
Solid oxide fuel cells (SOFCs) require current collectors with high heat and oxidation resistance, but materials like noble metals and Inconel are costly, and nickel-based collectors face issues with corrosion in harsh environments, leading to low gas fluidity and conductivity when using carbon or nickel alone.
Innovation Solution
A porous current collector is developed using a nickel porous base material coated with a tin-containing alloy layer and a silver layer, forming a strong silver layer with sufficient bonding strength, which enhances corrosion resistance and conductivity while reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a nickel porous base material is used as current collector, then conductivity and cost are improved, but corrosion resistance deteriorates in the corrosive environment of fuel cell
Solution Approach 1:
The patent applies composite materials by creating a multi-layer structure consisting of a nickel porous base material combined with corrosion-resistant alloy layers (such as iron-chromium-nickel or cobalt-chromium-nickel alloys). This composite structure combines the high conductivity and cost-effectiveness of nickel with the superior corrosion resistance of chromium-containing alloys, resolving the contradiction between corrosion resistance and ease of manufacture.
2Reliability
If a silver layer is formed on nickel porous base material, then conductivity and cost are improved, but bonding strength deteriorates because nickel and silver do not form solid solution
Solution Approach 1:
The patent uses an iron-chromium-nickel or cobalt-chromium-nickel alloy layer as an intermediary between the nickel porous base material and the silver coating. This intermediate layer forms a solid solution with both nickel and silver, creating strong metallurgical bonding while maintaining the benefits of silver's high conductivity. This resolves the contradiction by introducing a mediating layer that enables strong bonding without complicating the overall manufacturing process.
3Reliability
If noble metals or Inconel are used for current collector, then corrosion resistance is improved, but production cost deteriorates
Solution Approach 1:
The patent applies local quality by providing corrosion resistance only where needed - through thin alloy layers (micrometer thickness) on the surface of the nickel porous base material. The bulk material remains cost-effective nickel, while the surface layers provide localized corrosion protection. This resolves the contradiction between corrosion resistance and production cost by applying protective properties only where necessary rather than using expensive materials throughout the entire structure.
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 cost-effective current collector with high durability and performance, improving corrosion resistance and conductivity, thus enhancing the power generation efficiency of SOFCs.
Implementation Method 1
a porous current collector comprising: a nickel porous base material, which is a porous base material having continuous pores and in which an alloy layer containing nickel and tin (Sn) is formed at least on a surface of the porous base material; and a silver layer formed on a surface of the nickel porous base material
Data Source
Figure 1
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AI summary
An inexpensive porous current collector having high durability is provided by forming a silver layer having high strength on a current collector formed from a nickel porous base material. Porous current collectors 8a and 9a are used in a fuel cell 101 including a solid electrolyte layer 2, a first electrode layer 3 on one side of the solid electrolyte layer, and a second electrode layer 4 on the other side. The porous current collectors each include: an alloy layer 60a, which is formed from a tin (Sn)-containing alloy, at least on the surfaces of continuous pores 52 of a nickel porous base material 60 having the continuous pores 52; and a silver layer 55 stacked on the alloy layer.