Electrochemical Methods of Transference Number Determination for Polymer Electrolyte Systems: A Comparative Study

Abstract

The transference number for cations, t+, is one of the most important parameters for characterizing polymeric and/or composite solid electrolytes. It expresses the contribution of the positive charge carriers to the total conductivity, which in turn reflects the degree of polarization due to the negative carriers in the electrolyte systems. Four electrochemical methods based on different equations commonly used for obtaining t+ are compared. A series of experiments were conducted with solid polymer electrolytes based on polyethylene oxide with and without TiO2 ceramic additive. Interestingly, the oldest method developed and presented four decades ago, emerges as the most simple, reliable, sensitive, repeatable, and stable option for determining t+ values over time.

Mechanically and Thermally Robust Gel Electrolytes Built from A Charged Double Helical Polymer

“…where R b is the bulk resistance of the electrolyte, R s is the interfacial resistance at steady state, I s is the steady state current, and ΔV is the applied voltage bias (10 mV). [68][69][70][71] The Li + transference number t DNMR was determined based on the diffusion coefficients using the following equation:…”

“…The Li + transference number t DC determined from the DC polarization method was determined using the following equation: $$$$\begin{equation}{t}^{{\mathrm{DC}}} = \frac{{{R}_{\mathrm{b}}}}{{\frac{{\Delta {\mathrm{V}}}}{{{I}_{\mathrm{s}}}} - {R}_{\mathrm{s}}}}\ \end{equation}$$$$where R b is the bulk resistance of the electrolyte, R s is the interfacial resistance at steady state, I s is the steady state current, and ΔV is the applied voltage bias (10 mV). [ 68–71 ] The Li + transference number t DNMR was determined based on the diffusion coefficients using the following equation: $$$$\begin{equation}{t}^{{\mathrm{DNMR}}} = \frac{{{c}_ + {D}_ + }}{{{c}_ + {D}_ + + {c}_ - {D}_ - }}\ \end{equation}$$$$where c + and c − are the molar concentrations of Li + and TFSI − , and D + and D − are the diffusion coefficients of Li + and TFSI − . The Li + transference number t ENMR was determined using the following equation: $$$$\begin{equation}{t}^{{\mathrm{ENMR}}} = \frac{{{{{\mu}}}_ + - {{{\mu}}}_{{\mathrm{Solv}}}}}{{{{{\mu}}}_ + + {{{\mu}}}_ - }}\ \end{equation}$$$$where µ + , µ − , and µ Solv are the measured mobilities of Li + , TFSI − , and PEGDME, respectively in the laboratory frame.…”

Understanding the Positive Effect of LATP in Polymer Electrolytes in All-Solid-State Lithium Batteries

“…R b and the low-frequency component Z d (0) of the impedance measurement were taken as shown in our previous study. 37 To extract t + values cells were run down to 0.01 Hz and values were calculated using the Sorenson and Jacobson formula:…”

Carbonate swollen lithiated Nafion electrolyte for quasi-solid-state lithium–sulfur batteries

“…polymeric electrolyte with a single ion conductor fully loaded with a polar solvent) is presented in the ESI. † Qualitatively, beyond the recognized limitation of the BVE method specically in the case of carbonate electrolyte due to the high resistance and instability of the solid electrolyte interphase formed on the lithium metal anode, 68,75 in polarized SLIC-SPE membranes, the deviation from the ideality of the transference numbers of cations, i.e. T + < 1, could be driven by the following.…”