Hydrogen desorption improvement of the LiNH2-LiH-KF composite

Interestingly, an obvious enhancement of the hydrogen storage property is achieved by introducing KF into the LiNH2-LiH system, while KCl, KBr or KI does not show obvious effect on improving the hydrogen storage properties of the LiNH2-LiH system. In comparison with that of the LiNH2-LiH composite, the hydrogen desorption curve of the LiNH2-LiH-0.05 KF composite becomes sharp and the dehydrogenation onset and peak temperatures are decreased by about 36 °C and 38 °C, respectively. The cyclic capacity and desorption kinetic of the LiNH2-LiH-0.05 KF composite in the tenth cycle are still much better than that of the LiNH2-LiH composite in the second cycle. Cyclic performance can be improved at least 4 times by addition of 5 mol% KF. Detailed structural investigations reveal that during the heat-treatment, the doped potassium fluoride can react with LiH and convert to potassium hydride, which induces the improvement in hydrogen storage properties of the LiNH2-LiH system.