Long‐Life Lithium‐Ion Sulfur Pouch Battery Enabled by Regulating Solvent Molecules and Using Lithiated Graphite Anode

Abstract

AbstractThe development of lithium‐sulfur (Li‐S) batteries is severely limited by the shuttle effect and instability of Li‐metal anode. Constructing Li‐ion S batteries (LISBs), by using more stable commercial graphite (Gr) anode instead of Li‐metal, is an effective way to realize long‐cycle‐life Li‐S batteries. However, Gr electrode is usually incompatible with the ether‐based electrolytes commonly used for Li‐S batteries due to the Li+‐ether complex co‐intercalation into Gr interlayers. Herein, a solvent molecule structure regulation strategy is provided to weaken the Li+‐solvent binding by increasing steric hindrance and electronegativity, to accelerate Li+ de‐solvation process and prevent Li+‐ether complex co‐intercalation into Gr anode. Meanwhile, the weakly solvating power of solvent can suppress the shuttle effect of lithium polysulfides and makes more anions participate in Li+ solvation structure to generate a stable anion‐derived solid electrolyte interface on Gr surface. Therefore, a LISB coin‐cell consisting of lithiated graphite anode and S@C cathode displays a stable capacity of ≈770 mAh g−1 within 200 cycles. Furthermore, an unprecedented practical LISB pouch‐cell with a high Gr loading (≈10.5 mg cm−2) also delivers a high initial capacity of 802.3 mAh g−1 and releases a stable capacity of 499.1 mAh g−1 with a high Coulombic efficiency (≈95.9%) after 120 cycles.