Electrochemical Oxygen Sensor Electrode Coating for Zero-Oxygen Accuracy

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Solution Overview

Problem

Electrochemical oxygen sensors struggle to accurately measure low oxygen concentrations due to false readings in oxygen-free environments, limiting their measurement range.

Innovation Solution

The sensor includes a positive electrode with a catalyst layer coated with a surface layer containing Sn or Ni, which prevents metal elution reactions in oxygen-free conditions, using an aqueous electrolyte solution with a pH of 3 to 10 and a chelating agent to stabilize metal ions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an electrochemical oxygen sensor uses a conventional negative electrode with Sn or Sn alloy, then the sensor can operate at room temperature and provide inexpensive oxygen concentration measurement, but the sensor produces false readings indicating oxygen presence in oxygen-free environments due to metal elution reactions at the negative electrode

Engineering Contradiction:

Improvemeasurement reliabilityVSAvoidoxygen concentration measurement precision

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The invention applies local quality by creating a surface layer with specific composition (containing element M from Sn or Ni) on the positive electrode that is rich in catalytic metal. This localized modification at the positive electrode surface prevents metal elution reactions without changing the overall sensor structure or negative electrode composition, thereby improving measurement reliability in oxygen-free environments while maintaining measurement precision

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention uses composite materials by forming a surface layer that contains both element M (Sn or Ni) and catalytic metal on the positive electrode. This composite structure combines the benefits of metal elution prevention (from element M) with oxygen reduction catalysis (from catalytic metal), resolving the contradiction between measurement reliability and precision

Inventive Principle:

Principle #40Composite materials

2Reliability

If the electrolyte solution pH is outside the range of 3 to 10, then the sensor may show different electrochemical behavior, but the metal elution reaction increases causing unstable voltage readings and reduced measurement reliability

Engineering Contradiction:

Improvemeasurement reliabilityVSAvoidelectrolyte solution stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The invention applies parameter changes by specifically controlling the electrolyte solution pH to be within the range of 3 to 10. This parameter optimization minimizes metal elution reactions from the negative electrode while maintaining electrochemical activity, thereby improving measurement reliability and electrolyte solution stability simultaneously

Inventive Principle:

Principle #35Parameter changes

3Reliability

If a surface layer containing element M is formed on the positive electrode, then metal elution reactions are prevented and measurement reliability is improved, but additional manufacturing steps are required

Engineering Contradiction:

Improvemeasurement reliabilityVSAvoidmanufacturing simplicity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention applies preliminary action by forming the surface layer containing element M on the positive electrode before assembling the sensor with the electrolyte solution and negative electrode. This preliminary formation of the protective surface layer ensures metal elution prevention capability is built into the sensor structure, improving measurement reliability while allowing integration into the manufacturing process

Inventive Principle:

Principle #10Preliminary action

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

Enables reliable measurement of low oxygen concentrations, including zero oxygen environments, by preventing voltage increases and ensuring stable readings over time.

Implementation Method 1

the positive electrode includes a catalyst layer containing a catalytic metal

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 2

oxygen is reduced at a positive electrode, and a metal elution reaction occurs at a negative electrode, thus generating a current

Methodology Applied

Scientific EffectRedox reactions: Redox Reactions

Implementation Method 3

the surface layer containing the element M prevents a metal elution reaction in an oxygen-free environment

Methodology Applied

Scientific EffectMetal elution prevention:

Implementation Method 4

using an aqueous electrolyte solution with a pH of 3 to 10 and a chelating agent to stabilize metal ions

Methodology Applied

Scientific EffectChelation:

Data Source

PatentUS12529674B2Electrochemical oxygen sensor and method for manufacturing the same

Publication Date: 2026.01.20 MAXELL LTD

AI summary

An electrochemical oxygen sensor according to the present invention includes a positive electrode, a negative electrode, and an electrolyte solution constituted by an aqueous solution, in which the negative electrode includes a metal containing, as a main component, an element M selected from Sn and Ni, the electrolyte solution is an aqueous solution having a pH of 3 to 10, the positive electrode includes a catalyst layer containing a catalytic metal, and the catalyst layer includes, on a surface that is in contact with the electrolyte solution, a surface layer containing the element M.