A painter by profession, König was also interested in natural science. In 1931 he was elected assistant to the German leader of the Baghdad Antiquity Administration as head of the laboratory. In 1938 he made the first thorough examination of a curious clay jar in the National Museum of Iraq (of which he was the director), now known as the Baghdad Battery. In 1940, having returned to Berlin due to illness, he published a paper speculating that they may have been galvanic cells, perhaps used for electroplatinggold onto silver objects. In the museum König also discovered copper utensils from ancient Sumer, which were electroplated with silver.
The earthen jar is 5½ inches high and 3 inches across, with an asphalt plug held in place by a copper sheet rolled into a tube. The tube has a copper disc at the bottom, also held in place by asphalt.