The Bunsen cell battery is a zinc-carbon primary cell composed of a zinc anode in dilute sulfuric acid separated by a porous pot from a carbon cathode in nitric or chromic acid. The cell is named after its inventor, German chemist Robert Wilhelm Bunsen, who improved upon the Grove cell by replacing Grove's expensive platinum cathode with carbon in the form of pulverized coal and coke. Like Grove's battery, Bunsen's emitted noxious fumes of nitrogen dioxide. Bunsen used this cell to extract metals. Henri Moissan used a stack of 90 cells for the electrolysis of hydrogen fluoride to obtain fluorine for the first time.