Direct and reversible hydrogen storage of lithium hydride (LiH) nanoconfined in high surface area graphite

Abstract

LiH has great potential as a high capacity hydrogen storage material (12 wt.%), however its thermodynamic stability has so far precluded practical application. Temperatures near 700 °C are required for hydrogen release and uptake. Herein, we report on a novel method to realise hydrogen uptake and release under milder temperature conditions without using any catalyst or alloying. Through nanoconfinement within the pores (2–20 nm) of high surface area graphite (HSAG) LiH displayed remarkable hydrogen storage properties and was able to release 1.9 wt.% of hydrogen from 200 °C. Reversibility was also achieved under the moderate conditions of 300 °C and 6 MPa hydrogen pressure. This demonstrates that the properties of LiH are particle size dependent and thus leads to new possibilities to realise the potential of LiH as a practical high capacity hydrogen storage material.