High-Energy Quasi-Solid-State Lithium-Sulfur Batteries Based on Electrostatic-Nucleophilic Synergy

Abstract

Quasi-solid-state-polymer-electrolyte-based (QSSE-based) quasi-solid-state lithium-sulfur batteries (QSSLSBs) are an emerging research focus because they are safe and deliver high energy density. However, sluggish interfacial reaction kinetics involving the sulfur cathode and QSSE remains a core developmental bottleneck. Herein, we reveal that the cations and anions of tetrabutylammonium iodide (TBAI) promote S3 center dot- generation via a synergistic electrostatic-nucleophilic catalysis mechanism that accelerates lithium polysulfide conversion. Accordingly, we innovatively introduced TBAI into the cathode-QSSE interface to construct an QSSE with a catalytically active interfacial layer that realized enhanced interface reaction kinetics. The cycling performance of the assembled QSSLSBs: an average decay rate of only 0.038% per cycle over 1600 stable long cycles at 0.2 C; a capacity retention of 70.5% after 100 cycles at 0.1 C under a high sulfur loading of 6.5 mg<middle dot>cm-2. The synergistic electrostatic-nucleophilic catalysis strategy developed herein provides innovative insight that addresses the sluggish interfacial kinetics of the QSSLSB cathode.