Despite the fact that metal–organic frameworks (MOFs), carbon nanostructures and complex hydrides have shown an extraordinarily high storage capacity of above 10 wt%, there remains a lot of obstacles to overcome, such as poor cyclability, inadequate reversibility, and complex preparation. Among the three options (gas, liquid and solid) for hydrogen storage, the solid-state-based approach has been considered as one of the most promising ways for its high gravimetric and volumetric capacities and reasonable economics. The safe, effective, and economical storage of hydrogen is a key link in the whole hydrogen economy. To meet the future global carbon emission reduction target, the development of clean and renewable energy like hydrogen has become the need of the hour. With increasing the content of Laves phase, there appear more pathways for hydrogen desorption so that the hydrides are more easily dissociated, which may provide new insights into how to achieve hydrogen desorption in BCC HEAs at room temperature. The addition of Mn, Fe and Ni lead to precipitation of Laves phase, however, the kinetics did not improve further because of their own excellent hydrogen absorption. Moreover, Ti 4V 3NbCr 2 M ( M = Mn, Fe, Ni) alloys were also synthesized to destabilize hydrides. The dehydrogenation activation energy of HEAs’ hydride has been proved to decrease with decreasing VEC, which may be due to the weakening of alloy atom and H atom. Particularly, Ti 4V 3NbCr 2 alloy shows the hydrogen storage capacity of 3.7 wt%, higher than other HEAs ever reported. The three alloys with fast hydrogen absorption kinetics reach the H/ M ratio up to 2. Three types of TiVCrNb HEAs (Ti 4V 3NbCr 2, Ti 3V 3Nb 2Cr 2, Ti 2V 3Nb 3Cr 2) with close atomic radii and different valence electron concentrations (VECs) were designed with single BCC phase by CALPHAD method. We have investigated the crystal structure, microstructure and hydrogen storage performance of a series of HEAs in the Ti–V–Nb–Cr system. Although many studies reported rapid absorption kinetics, the investigation of hydrogen desorption is missing, especially in BCC HEAs. HEAs with body-centered cubic (BCC) structures present a high potential for hydrogen storage due to the high hydrogen-to-metal ratio (up to H/ M = 2) and vastness of compositions. Recently, high-entropy alloys (HEAs) designed by the concepts of unique entropy-stabilized mechanisms, started to attract widespread interests for their hydrogen storage properties.
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