The key technology for hydrogen energy effectively is to develop safe, economical and efficient hydrogen storage system. Among all the hydrogen storage technologies at present, solid-state hydrogen storage material has got a lot of attentions because of its outstanding advantages including high density, excellent cycle property, safe and convenient storage mode. Complex hydride material has the highest hydrogen storage density; and light metal complex hydride hydrogen storage systems (LMCHHSS) which have high hydrogen storage density and excellent hydrogen storage property are the research emphasis with good achievements. The decomposition mechanisms, thermodynamic and kinetic properties, cycling performances, crystal structures, research status of LMCHHSS, including borohydride system, alanate system and amide system, are discussed in the paper. At last, some promising research directions to reduce thermodynamic stability, improve kinetic property and cycling hydrogen storage property, such as binary or multicomponent composite system, efficient catalyst nanoparticle, superior reaction environment, or the comprehensive synergistic effect of the above, are suggested for the developing trends of the domain in the future.

Contents
1 Introduction
2 Light metal borohydride hydrogen storage system
2.1 LiBH₄ hydrogen storage system
2.2 NaBH₄ hydrogen storage system
2.3 KBH₄ hydrogen storage system
2.4 Mg(BH₄)₂ hydrogen storage system
3 Light metal alanate hydrogen storage system
3.1 LiAlH₄ hydrogen storage system
3.2 NaAlH₄ hydrogen storage system
3.3 Mg(AlH₄)₂ hydrogen storage system
4 Alkali metalamide hydrogen storage system
4.1 LiNH₂ hydrogen storage system
4.2 NaNH₂ hydrogen storage system
5 Conclusion and outlook