Oxygen-Consuming Electrode Fluoropolymer Coating for Chlor-Alkali Stability

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Solution Overview

Problem

Existing oxygen-consuming electrodes for chlor-alkali electrolysis face challenges in achieving high operational stability and preventing gas and liquid breakthroughs, limiting their height and requiring complex constructions to manage pressure and prevent electrolyte intrusion into the gas space.

Innovation Solution

A fluoropolymer coating, soluble in solvents, is applied to the gas-facing side of the oxygen-consuming electrode, using copolymers like PDD and TFE, which are soluble in fluorinated solvents, to create a durable and permeable layer that prevents disruptive flooding and gas breakthroughs, even at higher pressures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the electrode height is increased to improve performance in membrane electrolyzers, then the productivity and efficiency are improved, but gas breakthrough and liquid intrusion occur disrupting the electrolysis process

Engineering Contradiction:
Improveelectrode performanceVSAvoidelectrolysis process stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

A hydrophobic coating layer is applied to the gas diffusion electrode, forming a thin film barrier that prevents liquid electrolyte penetration while allowing gas transport. This coating acts as a flexible shell that maintains the three-phase boundary integrity even at increased electrode heights, preventing both gas breakthrough and liquid intrusion that would otherwise occur in taller electrodes.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The electrode structure is enhanced by combining the gas diffusion layer with a hydrophobic coating layer, creating a composite material system. This composite structure integrates the catalytic functionality of the gas diffusion electrode with the protective barrier properties of the hydrophobic coating, enabling taller electrodes to maintain both performance and reliability.

Inventive Principle:
Principle #40Composite materials

2Reliability

If pressure compensation solutions are implemented to prevent gas and liquid breakthrough, then the reliability is improved, but the device complexity increases

Engineering Contradiction:
Improvepressure managementVSAvoidconstruction complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The hydrophobic coating layer provides self-regulating pressure management by inherently repelling liquid electrolyte while permitting gas transport. The coating automatically maintains the three-phase boundary without requiring external pressure compensation mechanisms, eliminating complex constructions and making the electrode self-sufficient in managing pressure平衡.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The hydrophobic coating acts as an intermediary layer between the gas diffusion layer and the external environment, mediating the interaction between gas and liquid phases. This intermediate barrier simplifies the overall system by providing a straightforward interface that naturally manages pressure and phase separation without complex auxiliary structures.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 fluoropolymer coating ensures long-term stability and prevents liquid or gas breakthroughs, allowing for operation at greater heights without complex constructions, enhancing the electrode's durability and performance in chlor-alkali electrolysis.

Implementation Method 1

a fluoropolymer coating, soluble in solvents, is applied to the gas-facing side of the oxygen-consuming electrode... to create a durable and permeable layer that prevents disruptive flooding and gas breakthroughs

Methodology Applied
Scientific EffectHydrophobicity: Hydrophobe

Implementation Method 2

The interface is generally held in the OVE by the surface tension of the electrolyte on the hydrophobic electrode material against the hydrostatic pressure of the electrolyte on the OVE

Methodology Applied
Scientific EffectSurface tension: Surface Tension

Data Source

PatentEP2461402B1Oxygen-consuming electrode and method for its production
Publication Date: 2016.09.21 COVESTRO DEUTSCHLAND AG

AI summary

An oxygen-consuming electrode, particularly for use in chlor-alkali electrolysis, with a novel coating is described. A manufacturing process for the oxygen-consuming electrode and its use in chlor-alkali electrolysis or fuel cell technology are also described. The oxygen-consuming electrode comprises at least one insoluble polymer, a catalyst, and a coating with a soluble fluoropolymer.