Hierarchical Porous Li2Mg(NH)2@C Nanowires with Long Cycle Life Towards Stable Hydrogen Storage

The hierarchical porous Li2Mg(NH)(2)@C nanowires full of micropores, mesopores, and macropores are successfully fabricated via a single-nozzle electrospinning technique combined with in-situ reaction between the precursors, i.e., MgCl2 and LiN3, under physical restriction upon thermal annealing. The explosive decomposition of LiN3 well dispersed in the electrospun nanowires during carbothermal treatment induces a highly porous structure, which provides a favourable way for H-2 delivering in and out of Li2Mg(NH)(2) nanoparticles simultaneously realized by the space-confinement of the porous carbon coating. As a result, the thus-fabricated Li2Mg(NH)(2)@C nanowires present significantly enhanced thermodynamics and kinetics towards hydrogen storage performance, e.g., a complete cycle of H-2 uptake and release with a capacity close to the theoretical value at a temperature as low as 105 degrees C. This is, to the best of our knowledge, the lowest cycling temperature reported to date. More interestingly, induced by the nanosize effects and space-confinement function of porous carbon coating, a excellently stable regeneration without apparent degradation after 20 de-/re-hydrogenation cycles at a temperature as low as 130 degrees C was achieved for the as-prepared Li2Mg(NH)(2)@C nanowires.