Manganese hexacyanoferrate derived Mn3O4 nanocubes-reduced graphene oxide nanocomposites and their charge storage characteristics in supercapacitors

Mn 3 O 4 -reduced graphene oxide (RGO) nanocomposites were prepared by chemical decomposition of the manganese hexacyanoferrate (MnHCF) complex directly on the graphene surface. XRD studies revealed the formation of crystalline hausmannite Mn 3 O 4 nanocubes in the as-prepared nanocomposites without any heat treatment. The FE-SEM images showed the formation of Mn 3 O 4 nanocubes on the graphene surface in the as-prepared nanocomposites. HR-TEM studies confirmed the homogeneous dispersion of ∼25 nm Mn 3 O 4 nanocubes on graphene nanosheets. The amount of Mn 3 O 4 nanocubes and graphene in the nanocomposites was estimated using TGA analysis from room temperature to 800 °C in air. The FT-IR and Raman spectroscopic analysis confirmed the functional groups in the nanocomposites and defects in graphene nanosheets in the nanocomposites. Cyclic voltammetry and galvanostatic charge-discharge experiments demonstrated a high specific capacitance of 131 F g −1 in 1 M Na 2 SO 4 electrolyte at a current density of 0.5 A g −1 for the RGM-0.5 nanocomposite. A capacitance retention of 99% was observed for 500 charge-discharge cycles at a current density of 5 A g −1 , which conformed the excellent stability of the RGM electrodes. The prepared Mn 3 O 4 -RGO nanocomposites are promising for electrochemical energy storage. Mn 3 O 4 nanocubes-RGO nanocomposites were prepared by decomposition of manganese-hexacyanoferrate on graphene and a specific capacitance of 131 F g −1 was obtained at 0.5 A g −1 in 1 M Na 2 SO 4 .