Hydrogen absorption enhancement of nanocrystalline Li3N/Li2C2 composite

A nanocrystalline composite of lithium nitride and lithium carbide was synthesized through melt infiltration of lithium metal into the mesopores of carbon aerogels followed by nitrogenation with nitrogen gas. The structure, surface properties, and morphology of the prepared samples were examined by XRD, N2 adsorption at 77 K, FE-SEM, FE-TEM, and TPD/MS. It was found that some of the lithium metal reacted with the carbon to form lithium carbide, and some of the lithium metal was transformed into lithium nitride by nitrogenation, yielding a composite of lithium nitride and lithium carbide. Relative to the bulk lithium nitride, the lithium nitride in the composite showed a significantly enhanced sequential hydrogen absorption capacity and a lowered temperature of hydrogenation/dehydrogenation.

► Nanocrystalline Li3N/Li2C2 composite was synthesized through a new approach.
► Lithium metal was infiltrated into the mesopores of carbon aerogels.
► The lithium reacted partly with the carbon to form lithium carbide.
► Some of lithium metal was transformed into lithium nitride by nitrogenation.
► Li3N/Li2C2 composite showed significantly enhanced hydrogen storage properties.