Progresses on High-Entropy Nano-catalysts for Electrochemical Energy Conversion Reactions Nanostructured high-entropy materials (HEMs) have garnered significant attention as a burgeoning class of materials in the field of electrocatalysis, due to their exceptional structural and functional properties. Many milestones have been achieved in the last few years, making a timely review of these progresses critically important for the further development of this promising research area.