SOFC Interconnect Ni-Co Coating for Chromium Barrier Stability

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Solution Overview

Problem

In solid oxide fuel cells, the interfacial resistance of metallic interconnects increases due to the growth of chromium-containing oxides, leading to performance degradation as chromium evaporates and contaminates the cathode, necessitating a dense protective layer to maintain electrical properties at high temperatures.

Innovation Solution

A ceramic protective layer comprising Nickel (Ni) and Cobalt (Co) with a specific atomic percentage ratio of 1.5 to 9 is applied to the interconnect, providing excellent adhesion and electrical conductivity while preventing chromium contamination, and is manufactured using electroplating with a spinel structure oxide to ensure durability and low process costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a metallic interconnect is used in solid oxide fuel cells, then high electrical conductivity and mechanical strength are achieved, but chromium-containing oxide grows at the interface causing increased resistance and cathode contamination

Engineering Contradiction:

Improveelectrical conductivityVSAvoidchromium evaporation and contamination

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

A ceramic protective layer comprising Ni and Co with atomic ratio of 1:1.5 to 1:9 is introduced as an intermediary between the metallic interconnect and the cathode. This protective layer acts as a barrier that prevents chromium evaporation from the metallic interconnect while maintaining electrical conductivity, thereby solving the contradiction between using metallic interconnects for conductivity and preventing chromium contamination.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The interconnect structure is designed as a composite material system combining metallic substrate (for mechanical strength and base conductivity) with a ceramic protective layer (for chromium barrier and surface stability). The ceramic layer comprises Ni and Co in specific atomic ratios, creating a composite structure that leverages the advantages of both materials while mitigating their individual disadvantages.

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If a dense protective layer is applied to prevent chromium contamination, then cathode performance is maintained, but manufacturing complexity and cost increase

Engineering Contradiction:

Improvecathode contaminationVSAvoidcoating process complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The protective layer composition parameters are optimized with specific atomic ratios of Ni to Co (1:1.5 to 1:9) to achieve the desired protective function. By controlling the compositional parameters within this range, the coating achieves dense structure for chromium barrier while maintaining manufacturing feasibility and cost-effectiveness.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The protective layer is applied selectively on the surfaces of the metallic interconnect that are in contact with the cathode, providing localized protection where chromium contamination occurs. This targeted approach maintains the metallic properties in non-critical areas while providing ceramic protection only where needed, reducing overall manufacturing complexity.

Inventive Principle:

Principle #3Local quality

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 Ni-Co ceramic protective layer effectively suppresses chromium evaporation, maintains low electrical resistance, and prevents delamination, ensuring high electrical conductivity and long-term performance of the solid oxide fuel cell interconnect.

Implementation Method 1

the ceramic protective layer comprises Ni and Co, and the ratio of the atomic percentage (at %) of the Co to the atomic percentage (at %) of the Ni is 1.5 to 9... effectively suppresses chromium evaporation

Methodology Applied

Scientific EffectEvaporation suppression: