Improved hydrogen sorption kinetics of compacted LiNH 2-LiH based small hydrogen storage tank by doping with TiF 4 and MWCNTs

Kinetic properties of compacted LiNH2–LiH developed by doping with TiF4 and multi-walled nanotubes (MWCNTs) as well as upscaling to small hydrogen storage tank are proposed. During de/rehydrogenation, transition metal-based catalyst (TiF4) provides the catalytic effects on hydrogen dissociation/recombination, while MWCNTs benefit thermal conductivity and hydrogen permeability. Enhanced dehydrogenation kinetics is observed from single-step reaction at narrower and lower temperature range of 150–350 °C (100 °C lower than the compacted LiNH2–LiH without additives) together with long plateau temperature and constant hydrogen flow rate (50 SCCM) up to 30 min during desorption of the small tank. Hydrogen contents de/absorbed during 5–6 cycles increase from 1.90-2.40 to 3.10-4.70 wt % H2 (from 29 to up to 80% of theoretical capacity). Li5TiN3 detected upon cycling absorbs NH3 to form Li5TiN3(NH3)x, favoring hydrogen sorption properties of LiNH2–LiH system. Moreover, comparable reaction mechanisms and performances are found at different positions inside the tank of compacted LiNH2–LiH doped with TiF4 and MWCNTs. © 2020 Elsevier B.V.