400 °C operable SOFCs based on ceria electrolyte for powering wireless sensor in internet of things

Solid oxide fuel cells (SOFCs) can generate high-efficiency and clean power but face a high-temperature bottleneck that hinders their widespread application. If alternative electrolytes can be developed to reduce the operating temperatures, the application of SOFCs will possibly be expanded to more scenarios, such as power sources for the Internet of Things (IoT). Herein, as a proof of the concept, a 400 °C operable SOFC is developed based on a precipitation-method prepared CeO₂ electrolyte for powering wireless sensor in IoT system. Material studies indicate the CeO₂ electrolyte sample forms a coating structure with a thin layer of amorphous carbonate covering the surface of CeO₂ particles, which could result in fast hybrid proton and oxygen ion transport. The fabricated CeO₂ electrolyte-based SOFCs exhibit promising power densities of 0.275–0.650 W cm⁻² with open circuit voltages of 1.04–1.11 V at 400–500 °C, indicative of feasible cell operation at 400 °C. It is also found the cell has high repeatability and good stability for 150 h under different current densities. With the aid of a power management unit, the developed SOFC is further applied to charge a supercapacitor, for powering a customized IoT system to monitor environmental parameters. The charge process is fast and stable. Our study thus developed a 400 °C operable SOFC based on CeO₂ electrolyte and demonstrates the feasibility of SOFC as power sources for LoT technology for the first time.