Ultra-high reversible hydrogen storage capacity of Li₃N by graphene wrapping

Abstract Li 3 N was a promising hydrogen storage material due to its extremely high hydrogen storage capacity. However, the poor kinetic properties as well as the cycling performance further limited its commercial application. Herein, graphene interface-enhanced Li 3 N (Li 3 N-Gra) was prepared by rolling transfer of microspheres. The onset dehydrogenation temperature of Li 3 N-8 wt.%Gra was as low as 211°C without any metal-based catalyst, which is 58°C lower than that of blank Li 3 N. About 4.14 wt.% H 2 was released by Li 3 N-8 wt.% Gra at 300°C within 10 min. Specially, Li 3 N-8 wt.%Gra has been demonstrated to release 4.12 wt.% H2 at 300°C even after 40 cycles with 98.0% capacity retention. The drastically reduced Li 3 N particle size, elevated defect concentration, and abundant graphene interfaces together contributed to the improved Li 3 N-Gra kinetic performance. The stable and abundant graphene interfaces served as structural supports and spatial barriers, which effectively improved the cycling stability of Li 3 N. The method proposed in this work for obtaining graphene interface-enhanced Li 3 N by microsphere rolling transfer was expected to be applied to various hydrogen storage materials to improve their hydrogen storage properties.