LAUSR

Abstract Boosting the energy density of supercapacitors without sacrificing their power capability and cyclability is highly desired. Herein, we reported high-performance asymmetric supercapacitor device with high cycling stability using mesoporous manganese oxide nanococoons (MONCs) as positive electrode, and activated carbon (AC) as negative electrode. The mesoporous manganese oxide nanococoons exhibit excellent electrochemical performances because of their large surface area. The optimized asymmetric supercapacitor could be cycled reversibly in the high voltage range of 0–1.7 V in aqueous electrolyte, which exhibits a maximum energy density of 32 Wh kg−1 at a power density of 185 W kg−1 and still remains 21 Wh kg−1 at a power density of 1630 W kg−1. Importantly, such asymmetric supercapacitor exhibits superior long cycle life with ∼100% specific capacitance retained after ∼2700 cycles and ∼98% after 5000 cycles.