Characterization of the Effect of Cell Design on Li−S Battery Resistance Using Electrochemical Impedance Spectroscopy
ChemElectroChem, cilt.8, sa.5, ss.963-971, 2021 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 8 Sayı: 5
- Basım Tarihi: 2021
- Doi Numarası: 10.1002/celc.202100165
- Dergi Adı: ChemElectroChem
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Applied Science & Technology Source, Chemical Abstracts Core, Compendex, INSPEC
- Sayfa Sayıları: ss.963-971
- Anahtar Kelimeler: carbon-to-sulfur ratio, cell design, electrochemical impedance spectroscopy, electrolyte-to-sulfur ratio, lithium-sulfur batteries
- Boğaziçi Üniversitesi Adresli: Evet
Özet
The effect of two critical cathode design parameters, electrolyte-to-sulfur (E/S) and carbon-to-sulfur (C/S) ratios, on the kinetic and transport resistances in a Li−S cell is determined as a function of discharge depth by using electrochemical impedance spectroscopy. Electrolyte, charge transfer, and Li2S film resistances are identified as the major contributors to cell resistance. Both E/S and C/S ratios have a significant impact on cell resistance, predominantly at the early and final stages of discharge. The E/S ratio controls the cathode kinetics in the first plateau together with Li2S precipitation near the end of discharge. Consequently, the highest cell resistances are obtained for the cell with the lowest E/S ratio of 6 mL g−1. Increasing the E/S ratio up to 19 mL g−1 decreases the resistances considerably, no notable change is achieved after this point. On the other hand, the C/S ratio reflects a tradeoff between high electrochemically active surface area vs. sufficient and homogeneous S loading in the cathode. The minimum cell resistance is attained for the cell with C/S=1; any increase or decrease in the C/S ratio leads to higher resistances. The results suggest a mechanistic interpretation of the connection between cathode design and cell performance in Li−S batteries.