NiFe Nanosheet Anode for Stable Alkaline Water Electrolysis
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Solution Overview
Problem
Alkaline water electrolysis anodes experience performance deterioration when used with renewable energy sources that have large output fluctuations, leading to instability and reduced catalytic activity over time.
Innovation Solution
The use of a hybrid nickel-iron hydroxide nanosheet (NiFe-ns) as a catalyst component in the anode, dispersed in a common electrolyte supplied to both the anode and cathode chambers, enhances durability and maintains catalytic activity even under fluctuating power conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a nickel-based anode is used in alkaline water electrolysis with high-concentration alkali aqueous solution, then the anode stability in the electrolyte is improved, but the catalytic activity deteriorates when electric power with large output fluctuation (such as renewable energy) is used as power source
Solution Approach 1:
The patent uses a composite catalyst layer comprising nickel oxide and iron oxide (or iron hydroxide) on the nickel-based anode. This composite structure combines the electrochemical activity of iron compounds with the stability of nickel, creating a material that maintains catalytic activity under fluctuating power conditions while remaining stable in high-concentration alkali electrolyte.
Solution Approach 2:
The patent modifies the chemical composition parameters of the catalyst layer by incorporating iron oxide/ hydroxide in specific ratios (Fe/Ni ratio controlled). This parameter change transforms the surface properties of the nickel-based anode, enabling it to withstand potential fluctuations without significant performance degradation.
2Use of energy by moving object
If the operation temperature is increased to improve electric conductivity of the alkali aqueous solution, then the electric conductivity is improved, but the corrosiveness of the electrolyte increases
Solution Approach 1:
The composite catalyst layer of nickel oxide and iron oxide/hydroxide forms a protective surface structure on the nickel-based anode. This composite material resists corrosion from the high-concentration alkali electrolyte even at elevated temperatures, allowing the system to operate at higher temperatures for improved conductivity without excessive material degradation.
3Reliability
If renewable energy is used as power source for alkaline water electrolysis, then the environmental sustainability is improved, but the severe conditions (sudden start/stop and abrupt load fluctuation) cause performance deterioration of the nickel-based anode
Solution Approach 1:
The nickel-iron composite catalyst layer provides enhanced tolerance to the severe operating conditions caused by renewable energy integration. The iron oxide/hydroxide component stabilizes the nickel surface during frequent start-stop cycles and load fluctuations, extending the anode's service life while maintaining compatibility with sustainable energy sources.
Solution Approach 2:
The iron oxide/hydroxide in the composite catalyst layer acts as a protective buffer that anticipates and mitigates the harmful effects of potential fluctuations before they can damage the nickel-based anode structure. This beforehand cushioning effect prevents performance deterioration during abrupt load changes.
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
This approach stabilizes the catalytic activity of the anode over a long period, ensuring consistent electrolysis performance even with renewable energy sources, and allows for the use of versatile materials in the catalyst layer formation.
Implementation Method 1
alkaline water electrolysis in which the electrolysis performance is unlikely to be deteriorated and which is stable for a long period of time can be performed
Implementation Method 2
supplying a common electrolyte having particular constitution to an anode chamber and a cathode chamber that form an electrolytic cell
Implementation Method 3
A nickel-based material which is stable in a high-concentration alkali aqueous solution is used as an alkaline water electrolysis anode
Data Source
Figure 1~3
Figure 4(a)~4(c)
Figure 5
AI summary
The present invention realizes industrially excellent effects such that when electric power having a large output fluctuation, such as renewable energy, is used as a power source, electrolysis performance is unlikely to be deteriorated and excellent catalytic activity is retained stably over a longer period of time, and in addition, the present invention provides a technique that enables forming a catalyst layer of an oxygen generation anode, which gives such excellent effects, with a more versatile materials and by a simple electrolysis method. Provided are an alkaline water electrolysis method including supplying an electrolyte obtained by dispersing a catalyst containing a hybrid nickel-iron hydroxide nanosheet (NiFe-ns) being a composite of a metal hydroxide and an organic substance to an anode chamber and a cathode chamber, and using the electrolyte for electrolysis in each chamber in common, an alkaline water electrolysis method including supplying an electrolyte obtained by dispersing a catalyst containing the NiFe-ns to an anode chamber and a cathode chamber, and performing electrolytic deposition of the NiFe-ns in the electrolytic cell during operation to electrolytically deposit the NiFe-ns on a surface of an electrically conductive substrate having a catalyst layer formed on a surface of an oxygen generation anode, thereby recovering and improving electrolysis performance, and an alkaline water electrolysis anode.