Construction of Hierarchical MoSe₂ Hollow Structures and Its Effect on Electrochemical Energy Storage and Conversion

Metal selenides have attracted increased attention as promising electrode materials for electrochemical energy storage and conversion systems including metal-ion batteries and water splitting. However, their practical application is greatly hindered by collapse of the microstructure, thus leading to performance fading. Tuning the structure at nanoscale of these materials is an effective strategy to address the issue. Herein, we craft MoSe₂ with hierarchical hollow structures via a facile bubble-assisted solvothermal method. The temperature-related variations of the hollow interiors are studied, which can be presented as solid, yolk-shell, and hollow spheres, respectively. Under the simultaneous action of the distinctive hollow structures and interconnections among the nanosheets, more intimate contacts between MoSe₂ and electrolyte can be achieved, thereby leading to superior electrochemical properties. Consequently, the MoSe₂ hollow nanospheres prepared under optimum conditions exhibit optimal electrochemical activities, which hold an initial specific capacity of 1287 mA h g^-1 and maintain great capacity even after 100 cycles as anode for Li-ion battery. Moreover, the Tafel slope of 58.9 mV dec^-1 for hydrogen evolution reaction is also attained.