Self-assembled spongy-like MnO2 electrode materials for supercapacitors

Mesoporous spongy-like MnO2 has been synthesized via a facile and biphasic wet method, accompanied with tetraoctylammonium bromide (TOAB) as a soft template under ambient condition. A well-defined spongy morphology of MnO2 with uniform filament diameters 10–20 nm have been observed by FESEM, TEM, HRTEM, XRD, FT-IR,TGA-DSC studies. Further physical characterizations revealed that MnO2 sponges owned a large surface area of 155 m2 g−1 with typical mesoporous appearance. A specific capacitance value as high as 336 F g−1 was obtained. This improved capacitive behavior was attributed to the large surface area, morphology nature of nano-MnO2, and its broad pore size distribution.

Hightlights
► Spongy-like MnO2 has been synthesized via a facile and biphasic wet method.
► As-prepared MnO2 nanoparticles possessed uniform size (10–20 nm).
► MnO2 favored high surface area (155 m2 g−1) with mesoporous nanostructure.
► Spongy-like MnO2 exhibited the specific capacitor as high as 336 F g−1.