Hydrogen sorption kinetics and suppression of NH3 emission of LiH-sandwiched LiNH2-LiH-TiF4-MWCNTs pellets upon cycling

NH3 emission during decomposition of LiNH2-LiH composite reduces hydrogen storage capacity and poisons fuel cell catalysts. The idea of sandwiching LiNH2-LiH pellet with LiH layers (10-30 wt%), reacting with NH(3 )and transforming into H2 is proposed. The LiH-sandwiched LiNH2-LiH pellets show no sign of NH3 release with the hydrogen capacitates of 3.5-4.0 wt% H-2 during the 1st cycle. Upon cycling (the 2nd-6th cycles), decomposition of LiH-sandwiched LiNH2-LiH pellet with the low amount of LiH layer (10 wt%) shows NH3 signal, while that with 30 wt% LiH layers liberates only hydrogen with the storage capacities of 2.3-2.6 wt% H2. Effective dehydrogenation and reversibility of the 30 wt% LiH-sandwiched LiNH2-LiH pellet are explained by not only sufficient content and mechanical stability of LiH layers but also the formation of the new active phases (LiH(1-x)Fx and Li2NH1-(y)Fy). (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

NH3 emission during the decomposition of LiNH2-LiH composite reduces hydrogen storage capacity and poisons fuel cell catalysts. By sandwiching LiNH2-LiH pellets with LiH layers, the release of NH3 can be effectively reduced and the hydrogen storage capacity can be improved.