The Materials Project is an open-access database offering material properties to accelerate the development of technology by predicting how new materials–both real and hypothetical–can be used. The project was established in 2011 with an emphasis on battery research, but includes property calculations for many areas of clean energy systems such as photovoltaics, thermoelectric materials, and catalysts. Most of the known 35,000 molecules and over 130,000 inorganic compounds are included in the database.