Semiconductor heterostructure SrTiO₃/CeO₂ electrolyte membrane fuel cells

Semiconductor heterostructure SrTiO₃/CeO₂ (STO/CeO2) membrane was used as the electrolyte material of low-temperature solid oxide fuel cells. This STO/CeO₂ membrane demonstrated a high ionic conductivity of 0.24 S cm⁻¹ under fuel cell conditions at 550°C, and also its fuel cell delivered a maximum power output of 745.6 mW cm⁻² at the same temperature. Moreover, the high electronic conductivity of CeO₂ is blocked by the STO/CeO₂ semiconductor heterojunction, thus resulting in the open circuit voltage increasing from 0.90 to 1.09 V at 550°C. The semiconductor heterointerface is found to play an important role in inhibiting the electron transfer between CeO₂ particles. Thus, this work makes it feasibility of using semiconductor materials as the electrolyte by constructing heterojunctions to suppress the electronic conductivity.