Three-dimensional crisscross porous manganese oxide/carbon composite networks for high performance supercapacitor electrodes

• Three-dimensional inter-connected porous networks of manganese oxide/carbon composites were successfully developed.
• The powdery composite possesses good conductivity and favorable porosity.
• The composite electrode delivers an outstanding specific capacitance of 807 F g−1 at 1 A g−1.

Manganese oxide/carbon (MnOx/C) composites have been successfully prepared via a high temperature heat treatment method followed by the electrochemical oxidation. The presence of carbon not only enhances the electronic conductivity of manganese oxides (MnOx), but also provides more active sites for the transformation of manganese monoxide (MnO) during the galvanostatic charge–discharge process. Simultaneity, the interconnected porous structures of MnOx/C samples are believed to provide a continuous channel for the diffusion of electrolyte ion and shorten the diffusion length of ions involved in the charge/discharge cycling processes. Consequently, these advantages endow the MnOx/C electrode a better capacitance performance, a superior long-term cyclic stability and outstanding rate capability compared with pristine MnOx. More importantly, the composites show a fascinating capacitance of 807 F g−1 at 1 A g−1, which is much higher than the reported hydrous RuO2 electrodes. It can be easily speculated that MnOx/C composites will act as a promising electrode materials for designing high-performance supercapacitors.