Improvement of the hydrogen-storage
performances of Li-Mg-N-H system
Liu YF, Hu JJ, Xiong ZT, et al.
Abstract
Li2MgN2H2 can reversibly store more than 5.5 wt% hydrogen. However, the
high activation energy of hydrogen desorption poses a kinetic barrier for lowtemperature operation. In this work, the composition of the Li–Mg–N–H
system has been modified by the partial substitution of Mg or Li by Na. The
changes in structure and hydrogen absorption/desorption kinetics have been
investigated. It was found that the peak temperature for hydrogen desorption
was decreased by ~10 °C, and that the hydrogen absorption/desorption
isotherms were also significantly changed. Furthermore, the activation energy
calculated by the Kissinger’s approach was reduced after the substitution of
Mg or Li by Na. In addition, the different dehydrogenation structures were
detected at different molar ratios of Mg, Li, and Na.