NIST Discovery May Improve Hydrogen Storage

A researcher at the National Institute of Standards and Technology has achieved a breakthrough in the understanding of the structure of a new class of materials that can store large amounts of hydrogen for later release. The work is significant in terms of its potential impact on fuel cells and hydrogen storage for automobiles.

While hydrogen-powered vehicles already exist, they lack the ability to store sufficient quantities of hydrogen on-board safely. Research into automotive hydrogen use has recently focused on catalytic materials that can be used to generate hydrogen from common materials and substances stored on-board. Several materials already exist that can trap large amounts of hydrogen, but they're largely unsuitable for use in automobiles because they require high heat to release hydrogen.

The new material combines lithium amide with metal hydrides. Lithium amide can store a significant amount of hydrogen by weight (10 percent or better) and can do so reversibly, meaning that the store-and-release process can be repeated reliably over time, but lithium amide, like most other hydrogen-storing materials, requires high heat to initiate the process, and produces toxic ammonia as a by-product.

By combining the lithium amide with metal hydrides, which also store hydrogen, scientists have achieved a reversible storage process that occurs at a much lower temperature than lithium amide alone, and generates much less ammonia. Don't look for the lithium amide/metal hydride combination to power your car anytime soon. The major benefit of the discovery is in understanding how hydrogen enters and exits these storage systems, which can be used to develop better materials that perform the same way at low temperatures and without creating toxic by-products.

Source: NIST