Effects of single- and co-substitution of Ti on dehydrogenation of Mg 2 NiH 4 : A first-principles study

A review on design strategies for metal hydrides with enhanced reaction thermodynamics for hydrogen storage applications

“…They reported a reaction enthalpy of 50 kJ/mol H 2 associated with hydrogen storage for MgNi 0.86 Cr 0.03 , which was considerably lower than the reaction enthalpy of 67 kJ/mol H 2 for Mg 2 Ni . Wei et al studied the effect of Ti substitution on the dehydrogenation thermodynamics of Mg 2 NiH 4 via first‐principles calculations . They reported that the co‐substitution of Ti for Mg and Ni led to the formation of Mg 16 – x Ni 8 – y Ti x + y H 32 with distorted Ti―H octahedra and weakened Ni―H bonding in neighboring NiH 4 4− units, implying the destabilization of Mg 2 NiH 4 .…”

“…The ability of transition metal additives is not limited to improvements in the dehydrogenation kinetics of metal hydrides. Studies have been performed on the use of transition metals for lowering reaction temperatures by “doping”, which is the first approach for achieving favorable reaction thermodynamics . Li et al introduced Ti‐based additives, such as TiCl 3 , to investigate the effect of additives on the dehydrogenation properties of Mg(BH 4 ) 2 .…”

“…71 Wei et al studied the effect of Ti substitution on the dehydrogenation thermodynamics of Mg 2 NiH 4 via first-principles calculations. 72 They reported that the co-substitution of Ti for Mg and Ni led to the formation of Mg 16 73 They highlighted that the addition of TiF 3 reduced the particle size of the MgH 2 -Na 3 AlH 6 composite, leading to a significant reduction in the first stage of the onset hydrogen release temperature. Dong et al employed a ball-milling method to incorporate RbF into a LiNH 2 -LiH mixture with the aim of reducing its dehydrogenation temperature.…”