Determination of Pseudocapacitance Changes of Nickel Oxide NiO Electrode with the Use of Dynamic Electrochemical Impedance Spectroscopy

摘要

The electrochemical capacitors (ECs) are attractive energy storage devices which can be applied inmany electronic products (e.g., cameras, laptops, cell phones) or hybrid electric vehicles (HEV). Theenergy storage in ECs is based on capacitive (the electrical double layer charging/discharging) andpseudocapacitive (additional charge provided by faradic reaction) phenomena. Considering theelectrodes exhibiting pseudocapacitance, examination of their capacitance value is usuallycomplicated, mainly because of its dependence on applied potential. This paper presents the results ofevaluating the capacitance of the nickel oxide electrode material by the analysis of the impedancespectra obtained by Dynamic Electrochemical Impedance Spectroscopy (DEIS). The proposed solutionallows to acquire the detailed information about capacitance changes as a function of applied potential.Another applied technique, i.e. Atomic Force Microscopy (AFM) revealed no significant changes ofelectrode topography during polarization.