human
I've heard a lot of people talking about a new kind of fuel cell that can be used to power vehicles. I'm wondering what this is.
assistant
Fuel cells are devices that convert chemical energy from a fuel into electrical energy. They're often used in combination with batteries, which store the energy and supply it when needed. The most common type of fuel cell is called a proton exchange membrane (PEM) fuel cell. It uses a membrane made of a special material that allows protons to pass through it while blocking electrons. This creates an electric current that can be used to power a vehicle.