Transient voltammetry, chronopotentiometry

By multi-phase transient experiments , we mean those such as cyclic voltammetry (see Chap. 3) or current reversal chronopotentiometry [33] in which some sudden charge is made in the imposed conditions at some definite time (t = r, for example) after the experiment commences. To address such multiphase experiments, one usually treats each phase separately, the solution of the first phase providing details of the concentration profiles at t — t, which then serve as the initial conditions for the second phase. Likewise, the final conditions of the second phase provide the initial conditions for the third phase, if any, and so on. 

A number of electrochemical techniques were applied for the electrochemical analysis of Li electrodes in a large variety of electrolyte solutions. These include chronopotentiometry [230-233], potentiodynamic measurements (cyclic voltammetry) [88,89], transient methods (micropolarization) [81], fast OCV measurements [90,91] and impedance spectroscopy (EIS) [92-100], It should be noted that electrochemical analysis of Li electrodes is very complicated for the following reasons ... 

Transient technique — A technique whose response is time dependent and whose time dependence is of primary interest, e.g., -> chronoamperometry, -> cyclic voltammetry (where current is the transient), -> chronopotentiometry and -> coulostatic techniques (where voltage is the transient). A transient technique contrasts with steady-state techniques where the response is time independent [i]. Some good examples are cyclic voltammetry [i, ii] (fast scan cyclic voltammetry), the indirect-laser-induced-temperature-jump (ILIT) method [iii], coulostatics [i]. The faster the transient technique, the more susceptible it is to distortion by -> adsorption of the redox moiety. 

Platinum, glasslike carbon, and tungsten are often used as inert working electrodes for the fundamental electrochemical studies in the ionic liquids. For such transient electrochemical techniques as cyclic voltammetry, chronoamperometry, and chronopotentiometry, it is safer to use the working electrode with a small active area. This is because most of the ionic liquids will have low conductivity, and this often causes the ohmic drop in the measured potentials by the current flowing between the working and counter electrode. Microelectrodes may be useful for the electrochemical measurements in the case of handling low conductive media. 

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