Hydrogen is the lightest element in the universe, but storing it safely in a small rechargeable battery presented engineers with a challenge. The solution was to find metals capable of storing hydrogen in nickel metal hydride batteries securely.
Nickel-Metal Hydride Batteries Use Special Metals
Nickel-metal hydride (NiMH) batteries use special metal alloys that can absorb hydrogen during charging and release it during discharge. The hydrogen is not stored in a separate gas tank though. Instead, it becomes part of the alloy’s structure.
During the twentieth century, scientists investigated materials that could absorb and release hydrogen repeatedly. Some alloys based on lanthanum and nickel proved promising, while other research explored titanium- and zirconium-based materials.
These discoveries offered a potential solution to storing hydrogen in nickel metal hydride batteries. Nickel-cadmium batteries were useful and durable, but cadmium was toxic. Engineers wanted an alternative that could provide useful energy storage without relying on this metal.
Hydrogen-Storage Alloys Offered a New Possibility.
The hydrogen used in manufacturing these batteries generally comes from industrial hydrogen supplies. During production, the alloy is prepared so that it can absorb hydrogen and participate in the battery’s chemical reactions.
When the battery charges, hydrogen is stored within the negative electrode’s alloy. During discharge, it participates in reactions that release electrical energy to a connected device.
The Alloy Is Therefore An Active Battery Material
This ability to store hydrogen in solid materials helped make nickel-metal hydride batteries practical. The technology eventually became important in portable electronics and hybrid cars.
The breakthrough was not merely finding hydrogen, but discovering how to store it in a metal alloy and use it repeatedly to produce electricity.
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