N-doped reduced graphene oxide/Co0.85Se microflowers with high mass loading as battery-type materials for quasi-solid-state hybrid supercapacitors

In this work, we prepared N-doped reduced graphene oxide/Co0.85Se (N-rGO/CS) microflowers through a two-step method. Since introducing N-doped rGO, the fabricated N-rGO/CS electrode with a high mass loading (similar to 8.83 mg/cm(2)) exhibits high areal specific capacity of 0.522 mAh/cm(2) (4.24 F/cm(2)) at 1 mA/cm(2), and a long-term cycling stability (85.8% of capacity retention after 6000 charge-discharge cycles). This is mainly because N-doped rGO can increase specific area and electrical conductivity, enhance the electrochemical activity and effectively facilitate the electron/ion transport between the electrode and electrolyte. Besides, the quasi-solid-state hybrid supercapacitors (HSCs) assembled by the N-rGO/CS delivers a high volumetric specific capacity of 5.82 mAh/cm(3) at 1 mA/cm(2), excellent energy density of 4.65 mWh/cm(3) under 10.5 mW/cm(3) and eminement cycle stability (87.6% retention over 6000 cycles at 10 mA/cm(2)). (C) 2021 Elsevier B.V. All rights reserved.