Hydrogen is the most abundant and simple element in the universe, making it a particularly attractive option for delivering and storing clean energy. Hydrogen fuel can be used to generate electricity, power homes and vehicles, in batteries, and other applications.

But on Earth, hydrogen can only be found in combination with other elements, such as water (H₂O), which means it needs to be extracted. Hydrogen is commonly produced by splitting water into hydrogen and oxygen using an electric current, in a process called proton-exchange membrane water electrolysis. If the electricity is produced using renewable energy, such as solar or wind, the process can be entirely carbon-free. But using an electrolyzer to produce hydrogen is expensive. Electrolyzers use lots of energy and require catalysts made from scarce precious metals like platinum and titanium.

A Fuel Cell that Produces and Stores Hydrogen

To solve this problem, Pacific Northwest National Laboratory developed a hydrogen fuel cell that can both produce hydrogen and store it. Called a redox-flow cell—a hybrid between an electrolyzer and a redox-flow battery device—this new method replaces the inefficient oxygen electrode with an Fe²⁺/Fe³⁺ (iron redux reaction) catholyte and eliminates the need to use precious metal catalysts. The device is equipped with a regeneration cell that replenishes the Fe²⁺ ions through renewable resources, allowing for continuous production of hydrogen gas.

Hydrogen can be produced with clean energy—such as electricity from a wind turbine when it’s abundant and cheap—then stored for later use. When the electricity is no longer available, the stored hydrogen passes through a fuel cell to generate electricity again.

Application

Redox-Flow Cell provides both hydrogen producers and end-users—like fuel cell refueling stations and industrial electricity generator manufacturers—with a low-cost, carbon-free, and efficient way of producing hydrogen.