Stanford engineers have developed an efficient photoelectrochemical cell (PEC) that uses a mixed ion electron conductor (MIEC) heterojunction to enable high temperature (hundreds of oC) conversion of concentrated sunlight to chemical fuel (such as hydrogen). At the heart of the solid state PEC is a semiconductor light absorber coated with a thin MIEC layer for improved catalytic activity electrochemical stability and ionic conduction. This provides a facile path for the ionic carriers to reach the solid electrolyte. This integrated photo-thermochemical device captures both thermal and photon energy to recover solar energy that would otherwise be lost. The single-device isothermal design is potentially more scalable than more complex conventional thermochemical and hybrid photo-thermochemical water-splitting routes. This technology significantly enhances conversion of solar energy into chemical fuels to help overcome the inherently intermittent nature of solar radiation. The invention is a new class of solid-state PECs based on light absorber/mixed ion & electron conductor (MIEC) heterojunction that operates at temperatures significantly above ambient and utilizes both the light and thermal energy available from concentrated sunlight for solar fuel production. This method can efficiently convert solar energy and store it in chemical fuels. Applications: 1) Photoelectrochemical cell (PEC): efficient conversion of solar energy to chemical fuel to enhance total solar energy utilization 2) Low cost energy storage in solar power plants
1) Extended operating temperature - the MIEC layer allows this new class of PEC to operate at elevated temperature with concentrated solar flux 2) Increased efficiency 3) Good utilization of the solar spectrum 4) Potentially more scalable than alternative water-splitting technology