▎ 摘　　要

Nanofabrication using a "bottom-up" approach of hybrid electrode materials into a well-defined architecture is essential for next-generation miniaturized energy storage devices. This paper describes the design and fabrication of reduced graphene oxide (rGO)/polyoxometalate (POM)-based hybrid electrode materials and their successful exploitation for asymmetric supercapacitors. First, redox active nanoclusters of POMs [phosphomolybdic acid (PMO12) and phosphotungstic acid (PW12)] were uniformly decorated on the surface of rGO nanosheets to take full advantage of both charge-storing mechanisms (faradaic from POMs and electric double layer from rGO). The as-synthesized rGO-PMO12 and rGO-PW12 hybrid electrodes exhibited impressive electrochemical performances with specific capacitances of 299 (269 mFcm(-2)) and 370 Fg(-1) (369 mFcm(-2)) in 1M H2SO4 as electrolyte at 5 mAcm(-2). An asymmetric supercapacitor was then fabricated using rGO-PMO12 as the positive and rGO-PW12 as the negative electrode. This rGO-PMO12 vertical bar rGO-PW12 asymmetric cell could be successfully cycled in a wide voltage window up to 1.6 V and hence exhibited an excellent energy density of 39 Whkg(-1) (1.3 mWhcm(-3)) at a power density of 658 Wkg(-1) (23 mWcm(-3)).