Amorphous molybdenum sulfide and its Mo-S motifs: Structural characteristics, synthetic strategies, and comprehensive applications

Amorphous materials are one kind of nonequilibrium materials and have become one of the most active research fields. Compared with crystalline solids, the theory of amorphous materials is still in infancy because their characteristic of atomic arrangement is more like liquid and has no long-range periodicity. Recently, as the representative of amorphous materials, amorphous molybdenum sulfide (a-MoS_x) with unique physical and chemical properties has been studied extensively. However, considerable debate surrounds the structure–property relationships of a-MoS_x owing to its diverse Mo-S motifs. Herein, we summarize recent discoveries and research results regarding a-MoS_x, whose structural characteristics, synthetic strategies, formation criteria, and comprehensive applications are discussed in detail. Finally, this review is ended with our personal insights and critical outlooks over the development of a-MoS_x.