Development of a Microwave Sensor for Real-Time Monitoring of a Micro Direct Methanol Fuel Cell

• Published in: Sensors (Basel, Switzerland) Switzerland), 2024-02, Vol.24 (3), p.969
• Main Authors: Zhang, Shubin, Qiang, Tian, Jiang, Yanfeng
• Format: Article
• Language: English
• Subjects: Aqueous solutions; Collectors; Dielectric properties; Fuel cell industry; Fuel cells; methanol crossover; micro direct methanol fuel cell (μDMFC); microwave sensor; nonintrusive detection; online monitoring; Radio frequency; Sensors
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s24030969

Micro direct methanol fuel cells (μDMFCs) are a promising power source for microelectronic devices and systems. As the operating state and performance of a μDMFC is generally determined by both electrochemical polarization and methanol crossover, it is important to monitor the methanol concentration in μDMFCs. Here, we design and fabricate a microwave sensor and integrate it with a μDMFC for the online detection of methanol concentration in a nonintrusive way. The sensing area is set at the bottom of the anode chamber of a μDMFC which exhibits a maximum output power density of 28.8 mW cm at 30 °C. With a square ring structure, the dual-mode microwave sensor shows a sensitivity of 9.5 MHz mol L. Furthermore, the importance of methanol concentration monitoring is demonstrated in the long term. A relatively smooth methanol decline curve was obtained, which indicated a normal and stable operating status of the μDMFC. Derived from real-time recording data, fuel utilization was additionally calculated as 28.5%.