High-performance pseudo-capacitor energy storage device based on a hollow-structured copper sulfide nanoflower and carbon quantum dot nanocomposite

Transition metal sulfides are widely used in high-performance energy storage equipment due to its excellent electrochemical activity and electrical conductivity. In this study, we introduce a carbon quantum dot (CQD)-doped hollow CuS composite (CuS@CQDs) as a novel electrode material for advanced asymmetric supercapacitors through one-step solvothermal synthesis and an impregnation bonding method. The CuS@CQDs composites with uniform and hierarchical porous architecture possess high specific area and low specific resistance, which can facilitate the transport of electrolytes and electrons. The as-prepared CuS@CQDs-ICM electrode exhibits a maximum specific capacitance of 920.5 F g(-1) at a current density of 0.5 A g(-1) and an energy density of 44.19 W h kg(-1) at a power density of 397.75 W kg(-1) with an excellent cycling stability of 92.8% after 10,000 cycles. The satisfactory electrochemical perfor-mance can be attributed to the unique nanoflower-like hollow structure of the CuS@CQDs composites and the synergy between CuS and CQDs. (C) 2020 Elsevier Ltd. All rights reserved.