Modeling the effect of key cathode design parameters on the electrochemical performance of a lithium-sulfur battery

Erisen N., Emerce N. B., Erensoy S. C., EROĞLU PALA D.

International Journal of Energy Research, cilt.42, sa.8, ss.2631-2642, 2018 (SCI-Expanded, Scopus)

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 42 Sayı: 8
  • Basım Tarihi: 2018
  • Doi Numarası: 10.1002/er.4045
  • Dergi Adı: International Journal of Energy Research
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.2631-2642
  • Anahtar Kelimeler: carbon-to-sulfur ratio in the cathode, cathode design, electrochemical modeling, electrolyte-to-sulfur ratio in the cathode, lithium-sulfur battery
  • Boğaziçi Üniversitesi Adresli: Evet

Özet

A 1D model is developed for the Li-S cell to predict the effect of critical cathode design parameters—carbon-to-sulfur (C/S) and electrolyte-to-sulfur (E/S) ratios in the cathode—on the electrochemical performance. Cell voltage at 60% depth of discharge corresponding to the lower voltage plateau is used as a metric for calculating the cell performance. The cathode kinetics in the lower voltage plateau is defined with a single electrochemical reaction; thus, the model has a single apparent kinetic model parameter, the cathode exchange current density (i0,pe). The model predicts that cell voltage increases considerably with increasing carbon content until a C/S ratio of 1 is attained, whereas the enhancement in the cell voltage at higher ratios is less obvious. The model can capture the effect of the C/S ratio on the cathode kinetics by expressing the electrochemically active area in the cathode in carbon volume fraction; the C/S ratio in the cathode does not affect i0,pe in the model. On the other hand, the electrolyte amount has a significant impact on the kinetic model parameter such that increasing electrolyte amount improves the cell voltage as a result of increasing i0,pe. Therefore, in the model, i0,pe needs to be defined as a function of the electrolyte volume fraction, which is known to have a crucial effect on reaction kinetics.