Electrocatalysts play a pivotal role in advancing and leveraging new energy sources, exerting significant influence on the efficacy of energy storage and conversion processes. High-entropy materials (HEMs), encompassing entities like high- entropy alloys (HEAs), high-entropy oxides (HEOs), high-entropy carbides (HECs), and high-entropy metal sulfides (HESs), have garnered substantial attention as electrocatalysts in various electrochemical applications. HEMs offer several advantages as innovative electrocatalysts, including their high-entropy nature, slow diffusion characteristics, lattice distortion, and cocktail effects. These attributes confer unique atomic configurations and electronic structures, thereby enhancing electrocatalytic performance. Relative to conventional materials, HEMs furnish a greater abundance of active sites in pivotal reactions such as hydrogen evolution (HER), oxygen reduction (ORR), oxygen evolution (OER), and carbon dioxide reduction (CO2RR). Furthermore, they facilitate synergistic effects that optimize electronic configurations, thus enhancing catalytic efficiency. However, traditional synthesis methods for high-entropy materials face significant limitations, often yielding heterogeneous or polycrystalline materials primarily dictated by thermodynamics. These constraints severely restrict their potential applications in electrocatalysis. To overcome these challenges, ultrafast high-temperature synthesis techniques like Joule heating, laser ablation, and microwave assistance have been employed in the development of high- entropy electrocatalysts. These advanced methods capitalize on specific kinetic conditions to address issues such as the immiscibility of metal elements and the uncontrollable migration or aggregation of atoms. Consequently, they facilitate the creation of various defects, yielding high-entropy electrocatalysts with non-equilibrium structures. Such structures play a pivotal role in influencing the adsorption and activation of key intermediates in electrochemical reactions, thereby enhancing the activity, selectivity, and stability of the electrocatalysts. The review provides an overview of the strengths and weaknesses of ultrafast high-temperature synthesis methods, including Joule heating, microwave radiation, induction heating, laser ablation, spray pyrolysis, and fast-moving bed pyrolysis. These techniques showcase notable advantages in crafting high-entropy electrocatalysts. Additionally, the review delves into the structure-activity relationships within HEAs, HEOs, HESs, and HECs. It explores the impact of metastable structures inherent in high-entropy materials and the synergistic effects arising from the presence of multiple elements on electrocatalytic mechanisms. HEAs boast distinctive microstructures, exceptional thermal stability, and remarkable catalytic prowess. The strategy of ultrafast high-temperature synthesis presents an effective means of fabricating single-phase HEAs, yielding promising research outcomes in electrocatalysis. However, there remains a gap to bridge before reaching industrial application levels. Nonetheless, employing advanced characterization techniques in tandem with data-driven approaches could propel further strides in the industrialization of HEAs electrocatalysts. HEOs represent a novel category of high-entropy electrocatalysts synthesized through the ultrafast high-temperature synthesis approach. These materials harness a synergistic effect stemming from multiple active sites and elements within their electronic structure, thereby augmenting catalytic activity. On the other hand, HECs stand out as innovative materials renowned for their high temperature resistance and robustness, finding utility not only in aerospace applications but also in electrocatalysis. Nonetheless, the elevated synthesis temperatures required for refractory metal carbides have posed challenges to their advancement in electrocatalysis research. Despite these obstacles, HECs offer clear advantages in the realm of electrocatalysis. With continued breakthroughs in ultrafast synthesis technology, the exploration and application of HECs are poised for significant advancements. The application of ultrafast high-temperature synthesis technology holds promise for the production of other high-entropy electrocatalysts. As technology evolves, we can anticipate the emergence of similar novel catalysts. The unique advantages offered by the ultrafast high-temperature synthesis strategy position high-entropy electrocatalysts as promising contenders in the realm of electrocatalysis, paving the way for exploring new electrocatalytic mechanisms and enhancing performance levels. As advanced ultrafast synthesis technologies continue to evolve, high-throughput preparation emerges as a compelling avenue for future exploration. Further integrating these synthesis methods with advanced characterization techniques and machine learning holds the potential to expedite the discovery and application of additional novel high-entropy electrocatalysts.
