Monodisperse magnesium hydride nanoparticles uniformly self-assembled on graphene
Magnesium-based hydrides represent a particularly promising candidate for hydrogen storage because of their high gravimetric and volumetric hydrogen capacities, high abundance (≈2.5% of Earth's surface composition, and virtually in unlimited amounts in sea water), low cost, nontoxicity, and high safety. [ 1 ] Their thermodynamic stability, the slow kinetics of their reversible H 2 storage reaction, and their inherent low thermal conductivity, however, signifi cantly obstruct their practical application in fuel cells. [ 2,3 ] To date, one of the most effective techniques to relieve the kinetic barrier and/or thermodynamics stability of Mg-based hydrides is nanostructuring, [ 4 ] which could directly result in a larger surface-to-volume ratio of the particles, shorter solid-state diffusion distances for hydrogen, and/or decreased thickness of the H 2 -impermeable layer of MgO. [ 5,6 ] Extensive experimental and theoretical studies have recently demonstrated that decreasing the particle size is also capable of thermodynamically destabilizing Mg-based hydrides, leading to a further enhancement of hydrogen storage performance.