High-performance symmetric electrochemical capacitor based on graphene foam and nanostructured manga

What is it about?

We have fabricated a symmetric electrochemical capacitor with high energy and power densities based on a composite of graphene foam (GF) with ∼ 80 wt% of manganese oxide (MnO 2 ) deposited by hydrothermal synthesis. Raman spectroscopy and X-ray diffraction measurements showed the presence of nanocrystalline MnO 2 on the GF, while scanning and transmission electron microscopies showed needle-like manganese oxide coated and anchored onto the surface of graphene

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Why is it important?

Graphene foam/MnO 2 composite electrodes have been fabricated by hydrothermal deposition of MnO 2 from KMnO 4 , and their electrochemical properties have been tested in a symmetric device with Na 2 SO 4 as the electrolyte. The 3D porous network structure of GF allows for a uniform coating and high loading of α - and γ -MnO 2 needle-like structures. The composite exhibits a specific capacitance of 240 Fg− 1 at a current density of 0.1 Ag − 1 and no change in capacitance was observed after 1000