▎ 摘　　要

Herein, the microspheres 1-hour NaxMnO2 (NMO-1) and nanotubes (4 and 12) hour NaxMnO2 (NMO-4 and NMO-12) were synthesized as a cathode material via low-temperature time-controlled hydrothermal process. The nitrogen-doped reduced graphene oxide (N-rgo) as an anode material and it was prepared by annealing process. The aqueous asymmetric supercapacitors (AASCs) based NMO-1, NMO-12 and N-rgo exhibited wide potential window up to 2 V in 1 M Na2SO4 electrolyte. Furthermore, microspheres of NMO-1 with N-rgo showed an excellent electrochemical performance due to its high surface area and porous architecture, which exhibited specific capacitance of 94.6 F g (- 1), while nanotubes NMO-4 and NMO-12 were 28.3 F g (- 1) and 22.8 F g (- 1), respectively. The AASCs of microspheres NMO-1 and N-rgo delivered specific energy of 52.6 Wh kg(-1) at a specific power of 357.1 W kg(-1), and a specific power of 7.1 kW kg(-1) at specific energy of 7.9 Wh kg(-1). Those results demonstrated that microspheres of NMO-1 is better than nanotubes of NMO-4 and NMO-12 for the AASCs.