At the beginning of his research career, Eduard Justi was engaged in making quantum theoretical calculations of gases and vapors in the spectrum between low and high temperatures. He opened up new possibilities for the improvement of steam engines, gasoline and diesel engines, chemical reactions, meteorological problems, and those of internal and external ballistics. His work made it possible to apply laws of thermodynamics, long known, in numerical terms.
From theoretical thermodynamics Justi arrived at the physics and technology of the lowest temperatures. These were applied, among other things, to study the phenomenon of superconductivity. Justi turned to new technologies replacing fossil fuels in his late research years. Apart from solar cells, he was also a pioneer of fuel cell technology, which is current today. In 1972, he initiated the construction of the then unique high magnetic field facility at the TU Braunschweig.