Reduced graphene oxide (RGO)/birnessite-type manganese dioxide (MnO2) nanoarchitectures were fabricated by a rapid microwave-assisted hydrothermal route at low temperature (60 degrees C). Graphene oxide (GO) reduced in the presence of poly(sodium 4-styrenesulfonate) (PSS) and carbon nanotubes (CNTs) were introduced as conductors to fabricate three-dimensional (3D) electroactive nanoarchitectures. The microstructures of the nanoarchitectures were systematically characterized by SEM, TEM, and BET. The optimized nanoarchitectures were found to exhibit superior electrochemical performance. Their specific capacitance value reached 304 F g(-1) at 1 A g(-1) and even remained as high as 250 F g(-1) at 10 A g(-1) in 1 M Na2SO4 electrolyte. A negligible decline (2.5%) of the initial capacity was observed after 1200 cycles at 4 A g(-1).