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

• DOI: 10.1016/j.tsf.2022.139535
• Publication Date: 2022-10-07T02:26:35Z
• Authors: Deniz Kiymaz; Aykut Kiymaz; Serpil Tekoglu; Felix Mayr; Haluk Dincalp; Ceylan Zafer
• Keywords: Supercapacitor; Hollandite; Nanostructure; Performance; Manganese dioxide; Impedance; 02 engineering and technology; Chemical solution deposition; Redox; Electrolytes; Nanosheets; Mno2; 0210 nano-technology; Electrochemical impedance spectroscopy; Nanosheet; State; Spectroscopy

The authors acknowledge to Presidency of the Turkish Republic Department of Strategy and Budget for the financial support of Project Grant No: 2016K12-2841 and the Scientific and Technical Research Council of Turkey (TUEBITAK) for financial support of D. KIYMAZ in the frame of program 2218 with the Grant No.: 1929b011800282. Also, we would like to express our most profound appreciation to Prof. Dr. Niyazi Serdar SARICIFTCI and Prof. Dr. Markus SCHARBER for providing infrastructure and their knowledge.<br/>Presidency of the Turkish Republic Department of Strategy and Budget; Scientific and Technical Research Council of Turkey (TUEBITAK); [2016K12-2841]; [1929b011800282]<br/>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.<br/>