Potentiostatic intermittent titration technique

A milder version of the potentiostatic intermittent titration technique (PITT) consists in modifying the initial potential by small steps, may be 1 mV, recording the current after a constant delay, and waiting until it has decreased to almost zero before modifying again the potential (staircase voltammetry). This version gives more information (activity potential and capacity) about the different redox couples present in the electrodes which are successively electroactive, but needs more sensitive equipment. 

Huggins and colleagues proposed the PITT in 1979 [17]. This technique also aims to determine the diffusion coefficient of diffusing species from Fick s equations. The solid particles are supposed to have initially a homogeneous concentration [18]. 

FIGURE 1.7 Schematic representation of the time dependence of current after a constant potential pulse. (From Wen, C.J., et al., J. Electrochem. Soc., 126, 2258, 1979.) 

VM is the molar volume of the host material for the Li ion intercalation for instance From Equations 1.17 and 1.18, 

If the current decay does not follow the Cottrel equation, l4t is not constant and it is replaced with max(/Vt). A 2 is the charge passed through the electrode when the current has decreased to less than 1% of its initial value [18], 

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Actually, the only report on MnO anode material before our recent publication indicates that MnO powder electrode could be discharged and charged under a very small current density (1/300 C) by a potentiostatic intermittent titration technique (PITT) mode. Pure phase MnO thin film was prepared. It was surprising to find that MnO thin film shows good rate performance and cyclic performance, as shown in Fig. 5.23. Similar performances and polarizations are also observed in the cases of MnO powder materials. ... 

A general view ofthe mechanisms and kinetics of the doping processes (using EIS), and a quantitative evaluation of the chemical diffusion coefficients of electronic and ionic charge carriers with the use of small-amplitude techniques (often called potentiostatic and galvanostatic intermittent titration techniques PITT and GITT, respectively [29]). 

The experiment was made under potentiostatic conditions. This is called potential intermittent titration technique (PITT). 

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