Zwitterion-Modified Li-S Separator for Li-Ion Acceleration and Redox Kinetics Mediation
발표자
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초록
내용
In this work, we present an effective means to anchoring the zwitterionic sulfobetaine (SB) moieties on the separator surface, whereby the effective Li ion transport and facilitated polysulfide conversion could be concurrently accomplished. To construct the platform for the zwitterion anchoring, polydopamine (PDA) was first introduced to promote the surface wettability and activity for further covalent binding, which robustly enabled to form PDA/SB-coated separators. As such, the zwitterion-functionalized separators resulted in greatly enhanced ionic conductivities and Li ion transference number thanks to the facile dissociation of lithium salt and selectively promoted interactions between Li cations and anionic sulfonate end groups in SB. Furthermore, as the conversion kinetics of sulfur could be improved by SB zwitterion, outstanding Li-S battery performances implementing ultra-low capacity decaying rate of 0.034% during long-term cycling tests up to 1200 cycles at 3.0 C.