Reaction Behavior of the Li-N-H Hydrogen Storage System with Boron Nitride as an Additive

This work begins with a discussion of the desorption, reaction rate-limiting step of a LiNH2-LiH hydrogen storage system. Using microstructural and thermodynamic studies, it explains the working mechanism of BN as an additive in Li-N-H hydrogen storage materials. High-energy wet ball milling with THF was applied to the LiNH2 + 1.2LiH mixture. The results obtained in this work show that the rate-limiting step of the desorption reaction depends on the degree of oxidation and amount of LiH in the system. The activation energy of the desorption reaction of both ball-milled LiNH2 and LiNH2 + 1.2LiH samples was reduced with BN as an additive. BN had no clear impact on the crystallite sizes of LiNH2 + 1.2LiH as-milled samples. However, it was found that BN stabilizes the crystallite sizes of LiNH2 + 1.2LiH samples during the high-temperature desorption and absorption processes.