For the first time, the appearance of an electric current during hydrogen with oxygen was observed by the English physicist William Grody back in 1839. The practical implementation of the process was carried out when creating energy sources replacing solar batteries on spacecraft, for example, according to the Apollo program in the sixties. A variety of technical challenges had to be overcome before the development of fuel cell vehicles could begin. But the pace of this work is exceptional.
So, the German company Daimler-Benz (even before the merger with the American Chrysler) in 1994 showed the first concept car on fuel cells NECAR-1. The improved NECAR-2 and NECAR-3 were created in the next three years, and in 1999 - the five-seat NECAR-4 hatchback and the small two-door F-Cell.
Sources: Аркадий ШВАРЦ, "Автомобиль будущего" - Журнал "Вестник" (Translated from Russian); DaimlerChrysler AG.