Stabilized Li-S batteries with anti-solvent-tamed quasi-solid-state reaction

The transition from dissolution-precipitation to quasi-solid-state sulfur reaction promises restricted polysulfide shuttle and lean electrolyte operation of Li-S batteries but incurs poor reaction kinetics. We here demonstrate that structural reorganization of sparingly solvating electrolytes (SSEs)—which is uniquely afforded by using low-density and low-cost aromatic anti-solvents—is vital for taming the quasi-solid-state sulfur reaction. Aromatic anti-solvents disrupt the interconnected structure of concentrated tetrahydrofuran (THF) electrolyte, uniquely creating subdomains that act to dissolve elemental sulfur, thus accelerating its consumption and re-formation while maintaining ultralow polysulfides solubility. The altered subdomains further result in robust solid electrolyte interphase (SEI) on lithium metal. As a result, the Li-S cell with a 3 mg_sulfur cm⁻² sulfur cathode can cycle steadily for ∼160 cycles with a lean electrolyte of 5 μL mg_sulfur⁻¹. Our work provides new insights into fine-tuning the electrolyte microstructure through solvent innovations for developing sulfur-based batteries that are high energy, cheap, and durable.