High-performance LT-SOFCs based on BaZr_0.8Y_0.2O_3−δ–Na₂CO₃ nanocomposite electrolyte for powering IoT system

Solid oxide fuel cells (SOFCs) are facing a bottleneck issue caused by their high operating temperatures that confines their widespread application, which is mainly due to the low ionic conductivity of the electrolyte. If the ionic transport in the electrolyte could be improved to reduce the operating temperatures of SOFCs, their application scenarios could be extended to more industrial activities, such as providing continuous power to Internet of Things (IoT) devices. In this work, as a proof of concept, a new nanocomposite electrolyte NBZY is proposed based on proton conductor BaZr_0.8Y_0.2O_3−δ and Na₂CO₃ for developing low-temperature SOFCs to power IoT sensors. Material characterization reveals the prepared BaZr_0.8Y_0.2O_3−δ–Na₂CO₃ (NBZY) forms a heterostructure, with a thin layer of amorphous Na₂CO₃ coating on the surface of BZY particles, which could create effective pathways to enable high proton conductivity in NBZY. The fabricated NBZY-based SOFCs exhibit high peak power densities of 245–943 mW/cm² and high open circuit voltages (OCVs) of 1.09 ~ 1.22 V at 400–500 °C due to the high proton conduction and good gas-tightness of NBZY. Durability tests demonstrate that the cells have good operation repeatability and can be stably operated for up to 90 h. Using a power management unit (PMU), the developed SOFC can be used to charge the supercapacitor within 35 min and successfully power the IoT sensor to measure the ambient temperature. This study develops a new high-performance composite electrolyte for low-temperature SOFCs and for the first time indicates the feasibility of SOFC for powering IoT systems.