Cyclic voltammetry of porous carbon is impacted by charge redistribution – understanding the mechanism and effects on performance metrics

Microscopic Model for Cyclic Voltammetry of Porous Electrodes

“…Interpreting CV data, however, is not straightforward. On the one hand, the transmission line (TL) circuit model, which was pioneered by De Levie [17] and further developed by Posey and Morozumi [18], can be used to fit the experimental CV curves of EDLCs [17,[19][20][21][22][23][24][25][26][27][28][29]. The "standard" TL model treats the porous electrode as circular cylindrical channels, of which the total resistance R tot and capacitance C tot are partitioned over a large number n of branches containing a capacitor of capacitance 2C and a resistor of resistance R 0 .…”

“…The "standard" TL model treats the porous electrode as circular cylindrical channels, of which the total resistance R tot and capacitance C tot are partitioned over a large number n of branches containing a capacitor of capacitance 2C and a resistor of resistance R 0 . However, the number of branches n that is used to fit the CV data by the TL model is typically of order unity, for instance n ¼ 1, n ¼ 5, and n ¼ 8 [19,20,24,25]. Hence, the fitted parameters provide no direct information about the microscopic characteristics of the EDLCs [30].…”

In situ P-doping induced Se vacancies enhance the supercapacitor performance of NiCo2Se4

“…This means that both surface control and diffusion control dominate the electrochemical reaction of the redox peak. In addition, the contribution of surface control and diffusion control to the total capacity can be quantitatively determined according to formula (5): 29,30…”

“…In addition, the charge storage kinetics of the NiCo 2 Se x -P 1 electrode was studied by analyzing the b value. At a fixed potential ( v ), the relationship between current density ( i ) and scan rate ( v ) was obtained using the following formula (4): 29,30 i = av b where a represents the parameter and b is the slope of the log( v )–log( i ) curve. According to Fig.…”

“…This means that both surface control and diffusion control dominate the electrochemical reaction of the redox peak. In addition, the contribution of surface control and diffusion control to the total capacity can be quantitatively determined according to formula (5): 29,30 i = h 1 v + h 2 v 1/2 where h 1 and h 2 are constants. h 1 v corresponds to the surface capacity and h 2 v 1/2 corresponds to the diffusion-controlled intercalation/de-intercalation process.…”