Gas Sensor Membrane Electrode Assembly with Ionic Liquid
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Solution Overview
Problem
Carbon monoxide sensors with liquid electrolytes face issues like electrolyte leakage, dry-out, and limited operating environments due to water evaporation, while solid electrolyte sensors require a water reservoir, adding cost and complexity.
Innovation Solution
A membrane electrode assembly (MEA) using a polymer membrane with retained ionic liquid, which eliminates the need for a water reservoir and allows operation in various environments by adjusting electrochemical potential based on humidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If liquid electrolyte is used in the sensor, then the sensor can operate with simple structure, but the electrolyte may leak or dry out causing sensor failure
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid to solid (ionomeric solid electrolyte), fundamentally altering its properties to eliminate leakage and dry-out issues while maintaining ionic conductivity for sensor operation
Solution Approach 2:
The patent uses composite materials by combining ionomeric materials (like Nafion) that possess both solid structural integrity and ionic conductivity, creating a material that functions as both structural support and electrolyte
2Reliability
If ionomeric solid electrolyte is used, then electrolyte leakage and dry-out are eliminated, but a water reservoir is required adding cost and complexity
Solution Approach 1:
The patent extracts and eliminates the water reservoir component from the sensor design, achieving this by modifying the ionomeric solid electrolyte to maintain performance without requiring external water supply, thereby simplifying the overall device structure
Solution Approach 2:
The ionomeric solid electrolyte is designed to self-maintain its humidity levels through its inherent properties, eliminating the need for an external water reservoir and making the system self-sufficient
3Stability of the object's composition
If water reservoir is integrated with the sensor, then humidity levels in the ionomeric solid electrolyte are maintained, but cost, size, and complexity increase
Solution Approach 1:
The patent removes the water reservoir from the sensor design by developing ionomeric solid electrolytes that can maintain stable humidity levels through their inherent material properties, eliminating the need for external water supply mechanisms
4Adaptability or versatility
If the sensor is open to the gas being tested, then gas sensing function is enabled, but the water reservoir is subject to evaporation shortening sensor life
Solution Approach 1:
The patent eliminates the water reservoir that was vulnerable to evaporation by using ionomeric solid electrolytes with sufficient water vapor retention, thereby extending sensor life while maintaining open-gas sensing capability
Solution Approach 2:
The ionomeric solid electrolyte acts as a flexible membrane that selectively allows gas permeability for sensing while retaining water vapor, creating a barrier that prevents evaporation without compromising gas detection function
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 MEA provides stable and cost-effective gas sensing without the need for a water reservoir, maintaining performance across different humidity levels and environments.
Implementation Method 1
a polymer membrane disposed between the sensing electrode and the counter electrode, the polymer membrane comprising an ionic liquid retained therein
Implementation Method 2
The reaction that takes place at the sensing electrode (anode) is set forth as CO+H2O→CO2+2H++2e−. The electrons liberated at the anode are conducted to the cathode through a monitored circuit that measures current and/or voltage, with the current/voltage in this circuit being proportional to the concentration of CO in the gas being tested.
Implementation Method 3
The protons liberated by the reaction taking place at the anode are transferred through the electrolyte to the cathode
Data Source
AI summary
A membrane electrode assembly for a gas sensor is described that includes a membrane disposed between a sensing electrode and a counter electrode. The membrane is a polymer membrane, such as an ionomer, having an ionic liquid retained therein.