  Capacitance measurements from cyclic voltammetry, galvanostatic
chronopotentiometry and calculation of capacitance from imaginary part of
impedance are widely used in investigations of supercapacitors. The methods
assume the supercapacitor is a capacitor, while real objects correspond to
different equivalent electric circuits and show various contributions of
non-capacitive currents to the current which is used for calculation of
capacitance. Specific capacitances which are presented in F g-1 units in
publications not always refer to electric capacitance. The inadequateness of
the capacitance characterization has already resulted in groundless attribution
to supercapacitors of various systems with electrochemical responses of poorly
reversible electrochemical reactions. The number of publications that present
false capacitances is terrible and still increases. A widespread neglect of
energy dissipation in calculations of specific capacitance leads to further
confusion in the characterization of supercapacitors.
