Li–Mg–N–H-based combination systems for hydrogen storage

Metal–N–H-based materials are of particular interest as a group of new complex hydrides owing to their potential applications in hydrogen storage. A variety of metal–N–H-based systems have been developed so far for their hydrogen storage performances. This review deals with the Li–Mg–N–H-based combination systems which are widely recognized as one of the most promising hydrogen storage media for practical applications. The emphasis is on the structural characteristics of the lithium/magnesium amides/imides/nitrides, the hydrogen storage properties determined by the material compositions, the thermodynamics and kinetics of the hydrogen storage process, and the reaction mechanisms for de-/hydrogenation of the Li–Mg–N–H combination systems. The challenges and direction in further improving the hydrogen storage performances of the Li–Mg–N–H-based combination systems are pointed out as well.

► Progress in Li–Mg–N–H-based hydrogen storage system is reviewed.► Relationship between the hydrogen storage behaviors and the material compositions are discussed.► Improved thermodynamics and kinetics for hydrogen storage process are discussed.► Reaction mechanisms proposed presently for hydrogen storage in Li–Mg–N–H system are summarized.► Challenges in developing Li–Mg–N–H-based hydrogen storage system for practical applications are pointed out.