Regulation of a Solid-Electrolyte Interphase and Ion Transfer via Organic Lewis Acid for Stable Li–S Pouch Cells

Abstract

Li–S batteries have good application potential due to their high theoretical energy density/capacity, being widely studied in recent years. However, due to the high reactivity between Li and S and the low efficiency of ion transfer in electrolyte, side reactions and Li dendrite growth could easily happen and reduce the stability or the cycling life of Li–S batteries. In this work, a kind of Lewis acid, i.e., iodopentafluorobenzene (IPFB), is adopted as an electrolyte additive to regulate ion configurations and SEI formation. The Lewis acid property of IPFB could help adsorb anions in electrolyte, which could participate in SEI formation and weaken local space charge near the anode surface, hence realizing a uniform ion distribution and Li deposition. As a result, a long cycling stability of Li||Li cells for over 600 h at 3 mA cm–2 under 3 mAh cm–2 and a 40-cycle high stability at 0.4 C of Li–S pouch cells are achieved. The induction of Lewis acid into electrolytes could be a potential and facile strategy for realizing uniform Li deposition and high-performance Li–S pouch cells