1. At the turn of the 20th century, electric automobiles were more popular than gasoline-fueled cars. Thomas Edison, the prolific American inventor, was interested in electric automobiles and developed an iron-nickel (Fe-Ni) battery to power them. He claimed that, due to their higher energy density, his batteries were superior to the lead-acid batteries then being used in automobiles. Today, the Edison battery is available in various voltages up to 48 V. It is used in London subway locomotives, in New York City subway cars, for standalone locations that are off the electric power grid, and for backup emergency power. The battery has a NiO(OH) cathode, an iron anode, and uses a mixture of KOH and LiOH as the electrolyte. The unbalanced half-reactions are: