Li-alloy/FeS cell design and analysis report

Mathematical Modeling of LiAl / LiCl , KCl / FeS Cells

“…We can use these primary data to calculate the thermodynamic, open-circuit potential for a range of compositions. The primary, open-circuit potential data are given for the eutectic ~omposition of the electrolyte as a reference condition and are of the form Ul,eut = al + biT [1] Table II gives the literature data for the coefficients in this equation, corresponding to the five reactions in Table I. Equation [1] yields the potential in volts and requires the temperature in kelvins.…”

“…The primary, open-circuit potential data are given for the eutectic ~omposition of the electrolyte as a reference condition and are of the form Ul,eut = al + biT [1] Table II gives the literature data for the coefficients in this equation, corresponding to the five reactions in Table I. Equation [1] yields the potential in volts and requires the temperature in kelvins. All the electrode reaction potentials are given relative to the two-phase (~, f~) LiA1 alloy reference electrode.…”

“…Pollard and Newman (4,5) use the value of e+ ~ = 0.555 for their model in their comparison to experimental cell discharge behavior. This initial porosity corresponds to a capacity density of 1.286 Ah/cm 3 (eFes ~ 0.445) and can be compared to the value of 1.4 Ah/cm 3 (eElS ~ 0.484, e+ ~ 0.516) that is used in the construction of the experimental cells (1). They used the slightly larger initial porosity in an attempt to account for the swelling of the positive electrode.…”

“…Lithium aluminum, iron sulfide cells were conceived for electric vehicle propulsion and energy storage applications (1). The melting point of the electrolyte in these cells usually restricts the operating temperatures to above 400~ The advantages of using a molten-salt electrolyte over an aqueous electrolyte include reducing electrolyte decomposition, ohmic resistancel and mass-transfer limitations.…”

“…In terms of engineering development, the LiA1/FeS cell is currently the most technically advanced system of this type. An extensive compilation of state-ofthe-art LiA1/FeS cell design, construction, and performance has been published by Gay et al (1). * Electrochemical Society Active Member.…”