Carbon Dioxide Sensor Electrode Composition for Stable Low-Temp Sensing
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Solution Overview
Problem
Conventional carbon dioxide sensors operate at high temperatures (600°C or more) and exhibit variability in electromotive force due to thickness-dependent conductive layers, making accurate measurement challenging.
Innovation Solution
A carbon dioxide sensor design featuring a solid electrolyte layer with anion conductivity, a detection electrode made of a mixture of metals (Au, Ag, Pt, Pd, Rh, Ru, Os, Ir), cation conductive carbonate, and lithium-containing oxide, and an intermediate layer of cerium oxide doped with lanthanum and rare-earth elements, allowing operation at lower temperatures and reducing electromotive force variability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional conductive layer (Li2ZrO3) is formed by reaction between magnesium-stabilized zirconia and lithium carbonate, then the ion bridge is electrochemically connected, but the thickness varies and electromotive force varies making accurate measurement difficult
Solution Approach 1:
The patent changes the formation method parameter from chemical reaction to physical deposition. By using a gas phase method to deposit Li2ZrO3 directly, the conductive layer thickness can be precisely controlled and kept uniform, eliminating the thickness variation caused by reaction-based formation. This resolves the contradiction between electromotive force consistency and manufacturing precision.
2Ease of manufacture
If a conductive layer is formed using a gas phase method, then the formation process is simplified, but it takes a long time to form the conductive layer
Solution Approach 1:
The patent optimizes the gas phase deposition parameters including temperature, pressure, and deposition rate to achieve a balance between process simplicity and formation time. By controlling these parameters, the conductive layer can be formed efficiently without excessive time consumption while maintaining the ease of manufacture advantage.
3Measurement precision
If the conductive layer thickness is varied, then the electromotive force varies, but maintaining constant thickness is difficult with reaction-based formation
Solution Approach 1:
The patent switches from reaction-based thickness control to deposition-based thickness control. By using gas phase deposition with controlled deposition rate and time, the conductive layer thickness can be precisely regulated, ensuring constant thickness across different sensors. This enables accurate and consistent carbon dioxide measurements by eliminating thickness-related electromotive force variations.
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 sensor achieves accurate carbon dioxide detection and measurement at temperatures lower than 600°C with stable electromotive force, enhancing detection performance and operational reliability.
Implementation Method 1
a solid electrolyte layer that is anion conductive
Implementation Method 2
the detection electrode is made of a mixture containing: one or more metals selected from the group consisting of Au, Ag, Pt, Pd, Rh, Ru, Os, and Ir; a cation conductive carbonate; and an oxide containing Li and at least one of Ce and Sm
Data Source
AI summary
A carbon dioxide sensor includes: a solid electrolyte layer that is anion conductive; a reference electrode disposed on one surface of the solid electrolyte layer; and a detection electrode disposed on the other surface of the solid electrolyte layer. The detection electrode is made of a mixture containing: (a) one or more metals selected from the group consisting of Au, Ag, Pt, Pd, Rh, Ru, Os, and Ir; (b) a cation conductive carbonate; and (c) an oxide containing Li and at least one of Ce and Sm. The solid electrolyte layer is preferably oxide ion conductive, and the cation conductive carbonate is preferably lithium ion conductive.