High-entropy alloy nanoparticles (HEA-NPs) are important class of materials with significant technological potential. However, the strategies for synthesizing uniformly dispersed HEA-NPs on granular supports such as carbon materials, γ-Al₂O₃, and zeolite, which is vital to their practical applications, are largely unexplored. Herein, we present a fast moving bed pyrolysis strategy to immobilize HEA-NPs on granular supports with a narrow size distribution of 2 nm up to denary (MnCoNiCuRhPdSnIrPtAu) HEA-NPs at 923 K. Fast moving bed pyrolysis strategy ensures the mixed metal precursors rapidly and simultaneously pyrolyzed at high temperatures, resulting in nuclei with a small size. The representative quinary (FeCoPdIrPt) HEA-NPs exhibit high stability (150 h) toward hydrogen evolution reaction with high mass activity, which is 26 times higher than the commercial Pt/C at an overpotential of 100 mV. Our strategy provides an improved methodology for synthesizing HEA-NPs on various supports.

Aluminum is a naturally abundant, trivalent charge carrier with high theoretical specific capacity and volumetric energy density, rendering aluminum-ion batteries a technology of choice for future large-scale energy storage. However, the frequent collapse of the host structure of the cathode materials and sluggish kinetics of aluminum ion diffusion have thus far hampered the realization of practical battery devices. Here, we synthesize Al_xMnO₂·nH₂O by an in-situ electrochemical transformation reaction to be used as a cathode material for an aluminum-ion battery with a configuration of Al/Al(OTF)₃-H₂O/Al_xMnO₂·nH₂O. This cell is not only based on aqueous electrolyte chemistry but also delivers a high specific capacity of 467 mAh g⁻¹ and a record high energy density of 481 Wh kg⁻¹. The high safety of aqueous electrolyte, facile cell assembly and the low cost of materials suggest that this aqueous aluminum-ion battery holds promise for large-scale energy applications.