Analyzing the composite heterostructure as an efficient electrolyte for low-temperature ceramic fuel cells

Abstract

The hexagonal wurtzite structure (ZnO) is a well-known multifunctional semiconductor, and it is widely used as an electrolyte in energy applications such as fuel cells. ZnO, an n-type semiconductor, can be used as the electrolyte in fuel cells despite its insufficient open circuit voltage and negligible current density. After incorporating GDC to create a semiconductor ionic GDC/ZnO heterostructure, the ionic conductivity increased to 0.16 S/cm, and the fuel cell performance improved to 802 mW/cm2 at 520 °C. It has been discovered that the heterostructure's energy band bending and built-in electric field play a crucial role in the ionic transport and inhibiting the electronic conduction of GDC/ZnO, resulting in a notable material ionic property and fuel cell performance. Also, relaxation time distribution analysis revealed that interfacial conduction plays a significant role in the ionic conduction of GDC/ZnO. These results indicate that ZnO, which has a wide bandgap, may be tailored to an ionic conducting electrolyte for fuel cell applications using a heterostructure approach and energy band alignment method.