Charge transport kinetics in flower like α-MnO2 nano-sheet and α-MnO2 nanowire based supercapacitors

In a supercapacitor, determining the cells' internal dynamics and limiting factors on the efficiency is essential for device designs. In this context, electrochemical impedance spectroscopy is a powerful tool in investigating device kinetics. This study explained the performance improvement in nanostructured MnO2 electrodes from a diffusion perspective. Firstly, we reported morphological features of flower-like nanosheet MnO2 and nanowire MnO2 with identical crystal structure (alpha-MnO2 phase) and capacitance-voltage properties. Then, the factors limiting the bias voltage-dependent capacitance efficiency were explained via electrochemical impedance spectroscopy by setting up a three-electrode system. Both resistance and capacitance vs. frequency plots provided important information on ion diffusion and charge transfer mechanisms.

Automated summary

This study explained the performance improvement in nanostructured MnO2 electrodes from a diffusion perspective using electrochemical impedance spectroscopy. The findings provide important insights for the design and optimization of supercapacitors.