Determination of Lithium-Ion Transference Number in Liquid Electrolyte with Analysis of Polarization Experiments

Transference number, a critical parameter in effective operation of electrolyte has been determined by electrochemical methods in electrolyte solution contains ethylene carbonate (EC)-propylene carbonate (PC)-ethyl methyl carbonate (EMC) and LiPF۶ salt at ambient temperature. The purposed procedure, the potentiostatic polarization (PP) method was carried out in a symmetrical Li | electrolyte | Li cell via electrochemical impedance spectroscopy and potentiostatic polarization methods. The calculations were based on analysis of resistances and initial and steady state currents. In this case, a small potential difference applied to induce the polarization leads to a small salt concentration gradient, resulting in anions to accumulate at the anode and deplete at the cathode. In this situation, only the cations are carrying the current at steady state, and the net anion flux is zero. The initial and steady current ratio, obtained from the chronoamperometric curve can be used to calculate the cation transference number. In the investigated system, transference number -۰.۴۹ was obtained. In this case, the electrolyte probably comprises of both positively-charged and negatively-charged triples cluster. If the negatively-charged triples are the dominated species, the negative transference number is obtained

کلیدواژه ها:

Lithium-Ion Battery ، Transference Number ، Potentiostatic Polarization Method