In-Situ Anode Activation via Cathode Catalytic Transfer

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Solution Overview

Problem

The existing methods for alkaline water electrolysis require separate ex-situ activation of anodes, which increases production costs and time, and do not allow for continuous activation during the electrolysis process.

Innovation Solution

In-situ anode activation is achieved by using a cathode with an anode catalytic material that releases and deposits onto the anode within the electrolytic cell during electrolysis, reducing anodic overpotential and maintaining the anode in an activated state through continuous replenishment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate ex-situ activation of anodes is performed before installation in the electrolytic cell, then the anode surface is activated with catalytic material, but production cost and activation time increase

Engineering Contradiction:
Improveanode activation stateVSAvoidproduction time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The cathode is pre-loaded with anode catalytic material (such as nickel sulfide or Raney nickel) during manufacturing. This preliminary preparation allows the catalytic material to be transferred to the anode during normal operation, eliminating the need for separate pre-activation steps and reducing production time while ensuring reliable anode activation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses the cathode itself as a source of catalytic material for anode activation. During electrolysis, the catalytic material automatically transfers from the cathode to the anode surface through electrochemical reactions, enabling the anode to self-activate without external intervention or separate activation equipment.

Inventive Principle:
Principle #25Self-service

2Reliability

If separate ex-situ activation of anodes is performed before installation in the electrolytic cell, then the anode surface is activated with catalytic material, but production cost increases

Engineering Contradiction:
Improveanode activation stateVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention combines the cathode and anode activation functions into a single system. The cathode is designed to contain and release anode catalytic material, merging the activation function into the cathode structure itself. This eliminates the need for separate activation equipment and processes, reducing manufacturing costs while ensuring reliable anode activation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cathode serves multiple functions: it performs its primary electrolysis function and simultaneously acts as a reservoir and source of catalytic material for anode activation. This multi-functionality reduces the need for separate activation systems and materials, thereby reducing production costs while maintaining reliable anode activation.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If anodes are activated before installation, then the anode is ready for electrolysis, but the activation cannot be maintained or replenished during operation

Engineering Contradiction:
Improveanode activation stateVSAvoidactivation duration
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The cathode continuously supplies catalytic material to the anode during electrolysis operation. This continuous replenishment ensures that the anode remains activated throughout its service life, maintaining reliable performance without interruption or degradation of the activation state.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The system recycles catalytic material from the cathode to the anode during operation. As the cathode releases catalytic material, it is transferred to the anode surface where it is retained and utilized. This recovery and reuse mechanism ensures continuous anode activation without loss of catalytic material from the system.

Inventive Principle:
Principle #34Discarding and recovering

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 method reduces the anodic overpotential, increases the efficiency of alkaline water electrolysis, and eliminates the need for pre-activation of anodes, allowing for sustained activation and reduced production costs.

Implementation Method 1

The anode catalytic material is released from the cathode into an electrolyte in the electrolytic cell by positioning the cathode in the electrolytic cell

Methodology Applied
Scientific EffectElectrochemical reaction: Electrolysis

Implementation Method 2

at least a part of the anode catalytic material so released is deposited at the anode by applying an electric voltage across the anode and the cathode

Methodology Applied
Scientific EffectElectrodeposition: Electrodeposition

Implementation Method 3

The diaphragm is gas tight. The anode and the cathode are separated by the diaphragm

Methodology Applied
Scientific EffectIon transport through membrane: Semipermeable Membrane

Data Source

PatentEP3417093B1A technique for in-situ anode activation by a cathode in an alkaline water electrolytic cell
Publication Date: 2020.04.29 SIEMENS AG
  • EP3417093B1 patent drawingFigure 1~2
  • EP3417093B1 patent drawingFigure 3~4
  • EP3417093B1 patent drawingFigure 5

AI summary

A technique for in-situ anode activation in an electrolytic cell for alkaline water electrolysis is presented. The electrolytic cell includes an anode, a cathode and a diaphragm. At least a part of a surface of the cathode includes an electrically conducting stable material and an anode catalytic material. The anode catalytic material is adapted to be released from the cathode in alkaline water and be deposited at the anode when an electric voltage is applied across the anode and the cathode. The diaphragm is disposed between and separates the anode and the cathode. The diaphragm is gas tight and is permeable to the anode catalytic material. The anode catalytic material is released from the cathode into the electrolyte in the electrolytic cell and is deposited onto the anode thereby reducing overpotential at the anode and thus activating the anode simultaneously as the alkaline water electrolysis is performed.