▎ 摘　　要

Although supercapacitors have higher power density than batteries, they are still limited by low energy density and low capacity retention. Here we report a high-performance supercapacitor electrode of manganese oxide/reduced graphene oxide nanocomposite coated on flexible carbon fiber paper (MnO2-rGO/CFP). MnO2-rGO nanocomposite was produced using a colloidal mixing of rGO nanosheets and 1.8 +/- 0.2 nm MnO2 nanoparticles. MnO2-rGO nanocomposite was coated on CFP using a spray-coating technique. MnO2-rGO/CFP exhibited ultrahigh specific capacitance and stability. The specific capacitance of MnO2-rGO/CFP determined by a galvanostatic charge-discharge method at 0.1 A g(-1) is about 393 F g(-1), which is 1.6-, 2.2-, 2.5-, and 7.4-fold higher than those of MnO2-GO/CFP, MnO2/CFP, rGO/CFP, and GO/CFP, respectively. The capacity retention of MnO2-rGO/CFP is over 98.5% of the original capacitance after 2000 cycles. This electrode has comparatively 6%, 11%, 13%, and 18% higher stability than MnO2-GO/CFP, MnO2/CFP, rGO/CFP, and GO/CFP, respectively. It is believed that the ultrahigh performance of MnO2-rGO/CFP is possibly due to high conductivity of rGO, high active surface area of tiny MnO2, and high porosity between each MnO2-rGO nanosheet coated on porous CFP. An as-fabricated all-solid-state prototype MnO2-rGO/CFP supercapacitor (2 x 14 cm) can spin up a 3 V motor for about 6 min. (C) 2013 Elsevier Ltd. All rights reserved.