Corrosion-Resistant Anode for Seawater Electrolysis
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Solution Overview
Problem
Grid-scale fresh water electrolysis for hydrogen fuel production strains vital water resources, and existing technologies face challenges in developing inexpensive electrocatalysts and electrodes that can sustain seawater splitting without chloride corrosion.
Innovation Solution
Development of an anode for oxygen evolution reaction in seawater, featuring a substrate with a passivation layer and an electrocatalyst layer, where the passivation layer includes sulfides or phosphides of metals, or an anionic layer is disposed between the substrate and the electrocatalyst layer, enabling efficient and corrosion-resistant water electrolysis in alkaline seawater.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrodes are used for seawater electrolysis, then water splitting can occur, but chloride corrosion severely limits durability and stability
Solution Approach 1:
A passivation layer comprising metal sulfide, metal phosphide, or metal selenide is introduced as an intermediary between the substrate and the electrolyte. This passivation layer acts as a protective barrier that repels chloride ions, preventing them from reaching and corroding the substrate, thereby significantly improving electrode stability and durability in seawater electrolysis
Solution Approach 2:
The electrode is designed as a composite structure combining a substrate with a passivation layer of metal sulfide, phosphide, or selenide. This composite material approach allows the electrode to simultaneously exhibit the desired electrical properties from the substrate and the corrosion resistance from the passivation layer, resolving the contradiction between conductivity and corrosion resistance
2Ease of manufacture
If inexpensive electrocatalysts are used to reduce cost, then manufacturing cost decreases, but performance and activity often suffer
Solution Approach 1:
The invention changes the chemical composition parameters of the electrode by incorporating passivation layers with specific metal compounds (sulfides, phosphides, selenides). This parameter change allows the use of more abundant and less expensive metals while maintaining high electrocatalytic activity through the optimized chemical environment provided by the passivation layer
Solution Approach 2:
The passivation layer provides locally optimized properties at the electrode-electrolyte interface, creating a favorable chemical environment that enhances electrocatalyst activity. The local quality of the passivation layer (its specific composition and structure) is tailored to improve reaction kinetics and reduce overpotential, thereby maintaining high productivity even with inexpensive materials
3Productivity
If high current density is achieved for energy efficiency, then productivity improves, but electrode degradation and corrosion accelerate
Solution Approach 1:
The passivation layer is applied in advance to the substrate before electrolysis begins. This preliminary protective action creates a pre-formed barrier that prevents chloride ions from attacking the substrate during high current density operation, thereby maintaining electrode integrity even under aggressive operating conditions that would otherwise cause rapid degradation
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 allows for sustained, energy-efficient seawater splitting with high current density and stability over 1000 hours, maintaining performance in harsh chloride conditions without noticeable corrosion or activity loss, utilizing a dual-layer NiFe-LDH/Ni3S2 anode that effectively repels chloride ions and forms a protective sulfate layer.
Implementation Method 1
utilizing a dual-layer NiFe-LDH/Ni3S2 anode that effectively repels chloride ions
Implementation Method 2
an electrocatalyst layer coating the passivation layer, wherein the passivation layer includes a sulfide of at least one metal
Implementation Method 3
forming a protective sulfate layer
Data Source
AI summary
A corrosion resistant anode is provided for oxygen evolution reaction in water including chloride ions. The anode includes: (1) a substrate; (2) a passivation layer coating the substrate; and (3) an electrocatalyst layer coating the passivation layer. Polyanion adjusted alkaline seawater electrolyte for hydrogen generation by electrolysis is also provided.