Galvanostatic cycling

Figure 3. Galvanostatic discharge curves (three-electrode cell) at 2 mA ofaPPy/CNTs pellet electrode (m=6.7 mg) before (2) and after (1) galvanostatic cycling in a symmetric capacitor (two electrode cell) at U=0.8 V. After the discharge (1), the electrode was charged up to 0.2 V (curve 3) and then discharged (curve 4).

The experimental tools for this research were chronopotetiometry (galvanostatic cycling),25 atomic force microscopy (AFM),26,27 scanning electron microscopy (SEM), and X-ray diffraction (XRD).21,25 It should be mentioned that the AFM imaging was conducted in-situ under potential control and in a special homemade glove box filled with highly pure argon atmosphere. This system has been already described in detail in the literature.28... 

The capacity and profile of the galvanostatic cycling curves are among the first key characteristics of the active material. 

Figure 4 presents typical results of galvanostatic cycling of purified natural graphite SLA1020 (formerly known as SL-20) from C/20 to C rates. The results have been summarized in Table 4. 

Table 1. Results of initial galvanostatic cycling of experimental 2016 coin cells with different types of graphite from SGC at C/20 rate (AU = 0.01 - 1.0V). Electrolyte - LP-30 from Merck (EC DMC + IMLiPFS). Counter electrode - Li foil.

Figure 8. Behavior of modified carbon-type materials in the course of galvanostatic cycling, current load 30 mA/g.

Consecutive Galvanostatic Cycling with Control of the Electrode Weight Loss... 

For purposes of studying of the possible mechanisms of electrochemical corrosion we have compared first of all the capacity loss for graphite electrodes with the loss of their mass during prolonged galvanostatic cycling (Table 2). 

Table 2. The Capacity and the Electrode Weight Loss forNGZ (GAK-1 type) and NGF ("Kropfmuhl Normalflocke ) During the Consecutive Galvanostatic Cycling up to...

Table 1. Performance parameters of2325 coin cells, as obtainedfrom galvanostatic cycling regime (0.5 mA).

Figure 21. FTIR spectra (diffuse reflectance mode) measured from a pristine LiNi02 composite cathode and with a cathode after galvanostatic cycling in Li salt/EC/DMC solutions. (Reproduced with permission from ref 292 (Figure 1). Copyright 2000 The Electrochemical Society.)...

If the reference electrode is correctly placed in the same equipotential as the working electrode, ohmic drop in the electrolyte may be negligible, but this may not be the situation in the bulk of the electrode. Quantitative determination of the electrode resistance is difficult when using voltammetry only. It is much easier using galvanostatic cycling. 

FIGURE 1.9 Galvanostatic cycling of the cell assembled with the PICA A-activated carbon in tetraethyl ammonium methane sulfonate 1.7 M in acetonitrile. (From Taberna, P.L., et al., J. Electrochem. Soc., 150 A292, 2003.)... 

FIGURE 8.26 Influence of the maximum voltage on the specific capacitance (per mass of one electrode) vs. the number of galvanostatic cycles of a symmetric two-electrode system based on a PPy/CNT composite (20wt% of CNT) in lmol L-1 H2S04. (From Khomenko, V., et al., Appl. Phys. A, 82, 567, 2006. With permission.)... 

Table 6 Typical Li Cycling Efficiency Values Calculated in Experiments in Which Li Was Deposited on Cu (5 C/cm2) Followed by Galvanostatic Cycling (1 mA/cm2) at 25% DOD (10-20 cycles)... 

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