Hydrogen storage performances and reaction mechanism of non-stoichiometric compound Li1.3Na1.7AlH6 doped with Ti3C2

Our previous work found that Li1.3Na1.7AlH6 possesses the lowest dehydrogenation onset temperature and the most favorable dehydrogenation thermal stability among Li-Na-Al-H compounds (Fan et al., 2017). In this work, additional Ti3C2 was introduced into Li1.3Na1.7AlH6 by ball milling to further enhance its dehydrogenation performances. According to the volumetric release curves, the initial dehydrogenation temperature of the sample Li1.3Na1.7AlH6 + 5 wt.%Ti3C2 was lowered by 35 K from that of the pristine Li1.3Na1.7AlH6. The dehydrogenation enthalpy values of Li1.3Na1.7AlH6 + 5 wt.%Ti3C2 (46.9 KJ mol H2−1) was also slightly lower than that of pristine Li1.3Na1.7AlH6 (49.7 KJ mol H2−1). It means that the doped Ti3C2 was actively involved in the reaction with Li1.3Na1.7AlH6 during the dehydrogenation process. The investigation by X-ray photoelectron spectroscopy (XPS) demonstrated that the reaction between Ti element and Li1.3Na1.7AlH6 was definitely carried out in which the zero valence of Ti was transformed into Ti3+.