Effect of Concentration on the Charge Storage Kinetics of Nanostructured MnO2 Thin-Film Supercapacitors Synthesized by the Hydrothermal Method

Aviraj M. Teli, Sonali A. Beknalkar, Sachin A. Pawar, Deepak P. Dubal, Tukaram D. Dongale, Dipali S. Patil, Pramod S. Patil, Jae Cheol Shin
2020 Energies  
In this study, amorphous manganese oxide (MnO2) nanostructured thin films were synthesized by a simple hydrothermal method. It is well known that the nanostructure plays a crucial role in energy storage applications. Herein, MnO2 nanostructures ranging from plates to flakes were synthesized without the use of any hard or soft templates. The 4+ oxidation state of Mn was confirmed by X-ray photoelectron spectroscopy. The MnO2 nanoflake structure has a specific surface area of 46 m2g−1, which
more » ... 6 m2g−1, which provides it with an excellent rate capability and an exactly rectangular cyclic voltammogram (CV) curve. The MnO2 nanoflake electrode has a high specific capacitance of about 433 Fg−1, an energy density of 60 Whkg−1 at 0.5 mAcm−2, and an excellent cyclic stability of 95% over 1000 CV cycles in 1 M aq. Na2SO4. Kinetics analysis of the charge storage in the nanoflake MnO2 sample shows a 55.6% diffusion-controlled contribution and 44.4% capacitive-controlled contribution to the total current calculated at a scan rate of 100 mVs−1 from the CV curve.
doi:10.3390/en13226124 fatcat:dpcgwozrnnfblf3nye3yinid3m