The Specific Capacitive Performances of the Manganese Oxyhydroxide/Carbon microcoil Electrodes for Supercapacitors

• MnOOH@carbon microcoil composites are successfully prepared.
• The pseudo-capacitive behaviors are extensively studied.
• The composites show good electrochemical performance.
• Energy storge mechanism of the electrode material is discussed.

Manganese oxyhydroxide (MnOOH)/carbon microcoil (CMC) composites are fabricated by micro-wave deposition. Then, their structures are characterized by scanning, transmission electron microscopy and X-ray diffraction. This work presents an extensive study of the pseudocapacitive performances of the as−prepared MnOOH@CMC electrodes in mild Na2SO4 electrolyte. It shows a specific capacitance of 396 F g−1 at a scan rate of 2 mV s−1. Moreover, these binary composites exhibit a good rate capability and cycling stability, retaining 137.6 F g−1 at current density of 2 A g−1 after 10,000 cycles. The good electrochemical performances of the composites are attributed to the ions from the electrolyte can easily diffusing into almost all pores of the electrode, leading to a complete insertion reaction.