Graphene quantum dots (GQDs) consist of nano-sized fragments of graphene, typically in the range of 1–10 nm in size, and are often synthesized under extreme conditions (oxidative/reductive cleavage, electrochemical shearing, and pulsed laser burning). Extremely small size and edge effects give GQDs a high specific surface area, abundant surface active sites, chemical stability, low toxicity, physiological stability, and tunable fluorescence properties. Thus, GQDs have been widely used in the field of energy, catalysis, environment, biology, and optics etc. However, the synthesis and application of GQDs in energy storage systems (ESSs) are still at an early stage and lack timely and up-to-date research progress. In view of this, we summarize and discuss the most recent progress of the application of GQDs and their derivatives in energy storage devices, with an emphasis on their roles in enhancing lithium/sodium/zinc-ion battery performance (e.g., improving ion diffusion kinetics, suppressing dendrite formation, and stabilizing electrode-electrolyte interfaces), boosting solar cell efficiency through light absorption tuning and charge transport optimization, and elevating supercapacitor energy density via high surface area and pseudocapacitive contributions. Finally, reasonable suggestions for future challenges are presented.

Energy storage materials are a key to the development of electrochemical energy storage technologies for meeting the higher requestor of novel paradigms in energy revolution. In recent years, high-entropy materials are developed as electrochemical energy storage materials based on the high entropy aspect as an emerging strategy of material design. In this review, high-entropy materials used in lithium ion battery, sodium ion battery and supercapacitor were represented. First, the basic concepts of high-entropy materials were briefly introduced, including the definition of high entropy and related effects. The structure and performance of high-entropy materials used as electrochemical energy storage materialswere comprehensively summarized. Some challenges arising from the development of high-entropy electrochemical energy storage materials were discussed. This review could provide a reference for rationally designing high-entropy electrode materials towards advanced energy storage and conversion.