One of the many technical obstacles to an environmentally cleaner hydrogen economy is finding a safe and practical way to store the reactive gas. Researchers from the National University of Singapore report that lithium nitride (Li₃N) is able to reversibly trap ~10% of its sample weight in hydrogen, or about 3.6 hydrogen atoms per molecule. However, temperatures above 275 °C are needed to desorb the hydrogen at atmospheric pressure, which are too high for practical applications.

Nevertheless, the material has a number of promising attributes. Ping Chen and colleagues found that Li₃N has favorable absorption kinetics—under 30 bar of hydrogen, a 500-mg sample at 255 °C captured most of the gas within 10 minutes. And the material can be recycled, with an overall capacity fluctuation of less than 10% after absorption/desorption cycles. (Nature 2002, 420, 302–304)