The enhanced de/re-hydrogenation performances of LiNa2AlH6 combined with two-dimension lamellar Ti3C2

In the present work, two-dimension lamellar Ti 3 C 2 was employed as additive of LiNa 2 AlH 6 . Volumetric dehydrogenation results informed that the onset dehydrogenation temperature of the ball milled LiNa 2 AlH 6   +   5 wt% Ti 3 C 2 sample was lowered by 68 K from that of pristine LiNa 2 AlH 6 . Isothermal pressure-composition (P-C-I) curves and van't Hoff plots demonstrated that the dehydrogenation enthalpy value (61 kJ mol H 2 −1 ) of LiNa 2 AlH 6  + 5 wt% Ti 3 C 2 was significantly reduced from the pristine LiNa 2 AlH 6 (68 kJ mol H 2 −1 ). By means of XPS analyses, it can be revealed that the destabilization of LiNa 2 AlH 6 should be resulted from the involvement of Ti and the yield of unidentified Ti 3+ species. Furthermore, it can be concluded that the lowering of dehydrogenation temperature was merely due to the thermal destabilization of LiNa 2 AlH 6 by Ti 3 C 2 , since Ti 3 C 2 hardly improved the dehydrogenation kinetics of LiNa 2 AlH 6 and reduced its activation energy . However, hydrogenation kinetics was slightly enhanced from the released products of LiNa 2 AlH 6   +   5 wt% Ti 3 C 2 .