Interfacial ionic conductivity of two−dimensional heterogeneous semiconductor ZnO composited with Zn2SiO4 derived from natural clay mineral vermiculite

Abstract

Solid ceramic fuel cells (SCFCs) are considered to be an irreplaceable energy conversion device in the future because of their high energy−conversion efficiency, non−combustion operation, and low−carbon emission. However, the commercialization of SCFCs is still limited by their higher operating temperatures (> 700 °C). In view of this challenge, we use two−dimensional silica derived from natural clay mineral vermiculite as the source of silicon to prepare Zn2SiO4, and then incorporate it with the ZnO material to design Zn2SiO4–ZnO heterogeneous semiconductor structure to realize fast carrier transport in electrolyte. We detected the electrochemical properties of Zn2SiO4–ZnO composite fuel cells at different molar ratios detail. The fabricated fuel cells demonstrate the best performance with power density of 692 mW cm−2 and a higher ionic conductivity of 0.23 S cm−1 for the fuel cell using 2Zn2SiO4–8ZnO composite as the electrolyte, which represents approximately 75% improvement comparing with pure ZnO fuel cell. Considering the rich reservation and ultra−low−cost of natural minerals, this work also provides an approach to develop nanocomposite energy materials derived from natural minerals for the application of green energy conversion.