As an emerging subclass of 2D materials, Xenes (e.g., borophene, silicene, germanene, stanene, phosphorene, arsenene, antimonene, and bismuthene) consist of one single element and have opened the door for various important applications. Benefiting from their impressive characteristics, including ultrathin folded structure, ultrahigh surface–volume ratio, excellent mechanical strength and flexibility, Xenes are considered as promising electrode materials in the field of electrochemical energy with large capacity, high rate, and high safety. This review provides a comprehensive summary of selected properties, synthetic challenges, and the latest theoretical and experimental advances in the energy‐related applications of Xenes, including Li/Na ion batteries, Li–S batteries, electrocatalysis, and supercapacitors. Finally, the challenges and outlook of this emerging field are discussed. The 2D monoelemental family (Xenes) and their fundamental electrochemistry are comprehensively reviewed and discussed. Strategies and challenges on engineering heterostructures, defects, encapsulation, modification of Xenes are deeply summarized. The relationship/interaction among fundamental electrochemistry, electrocatalysis, and energy storage (Li/Na ion batteries, Li/Na air batteries, supercapacitors, Li–S battery) is concluded and outlooked.