Proton Exchange Membrane Fuel Cell

A proton exchange membrane fuel cell, or PEMFC, generates electricity by splitting hydrogen into protons and electrons at its anode; the protons cross a solid polymer membrane to the cathode while the electrons travel through an external circuit, and at the cathode oxygen combines with both to form water, with the whole process running at a relatively low 50 to 100 degrees Celsius. Willard Thomas Grubb and Leonard Niedrach of General Electric invented the technology in the early 1960s, and the company early sulfonated polystyrene membranes were replaced in 1966 by Nafion, which performed far better. PEMFCs powered NASA Gemini spacecraft before alkaline fuel cells took over for Apollo and the Space Shuttle, and innovations in the late 1980s and early 1990s, including reduced platinum loading and thin film electrodes, made the technology commercially practical; the United States Department of Energy estimated a 2016 production cost of 53 dollars per kilowatt at a scale of 500,000 units a year. The Toyota Mirai is a major modern application of the technology in a production vehicle.