Kiymaz D.Kiymaz A.Tekoglu S.Mayr F.Dincalp H.Zafer C.2025-04-102025-04-102022http://hdl.handle.net/20.500.14701/45231In 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 (α-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. © 2022 Elsevier B.V.Article10.1016/j.tsf.2022.139535