Scalable fabrication of two-dimensional Bi2Se3 for high-performance supercapacitors

Although having an advantageous charge-discharge rate, supercapacitors, in terms of energy density, are still dwarfed by their battery counterparts, thereby hindering their industrial use. Two-dimensional (2D) Bi2Se3, which is characterized by high electrical conductivity, possesses a large theoretical specific capacity that has not been experimentally realized. In this study, we employed scalable electrochemical exfoliation to fabricate highquality Bi2Se3 nanosheets with a yield of over 95 %. These nanosheets were then applied as anode materials with the hitherto highest specific capacitance of 662.5 F/g at 1A/g to assemble asymmetric supercapacitors (ASCs) of Bi2Se3//NiCo2S4. The supercapacitors demonstrated an extraordinary energy density of 48 Wh/kg at a power density of 800 W/kg and efficiently drove devices such as perovskite-LEDs. This study reveals the huge potential of 2D Bi2Se3 as an efficient supercapacitor electrode via a primary Faradaic pseudocapacitive storage mechanism. The scalable production of this material is expected to stimulate its widespread and practical use.