He invented the first electric battery, the voltaic pile, in 1800, which produced a steady electric current from the chemical reaction of zinc and copper plates separated by brine-soaked paper
He conducted extensive experiments on electrolysis, electromagnetism, and electric motors, and established the laws of electrochemistry, which explain the relation between electric current and chemical changes
He invented the first rechargeable battery, the lead-acid battery, in 1859, which is still widely used in cars and other applications
He developed the nickel-iron battery, also known as the Edison battery, in 1901, which had a longer lifespan and higher efficiency than the lead-acid battery, and was used for electric vehicles, trains, and lighting systems
He invented the first nickel-cadmium battery, also known as the NiCd battery, in 1899, which had a higher energy density and lower self-discharge rate than the lead-acid battery, and was used for portable devices, aircraft, and satellites