Minimizing Carbon Content with Three‐in‐One Functionalized Nano Conductive Ceramics: Toward More Practical and Safer S Cathodes of Li‐S Cells

Abstract

Using porous carbon hosts in cathodes of Li‐S cells can disperse S actives and offset their poor electrical conductivity. However, such reservoirs would in turn absorb excess electrolyte solvents to S‐unfilled regions, causing the electrolyte overconsumption, specific energy decline, and even safety hazards for battery devices. To build better cathodes, we propose to substitute carbons by In‐doped SnO2 (ITO) nano ceramics that own three‐in‐one functionalities: 1) using conductive ITO enables minimizing the total carbon content to an extremely low mass ratio (~3%) in cathodes, elevating the electrode tap density and averting the electrolyte overuse; 2) polar ITO nanoclusters can serve as robust anchors toward Li polysulfide (LiPS) by electrostatic adsorption or chemical bond interactions; 3) they offer catalysis centers for liquid–solid phase conversions of S‐based actives. Also, such ceramics are intrinsically nonflammable, preventing S cathodes away from thermal runaway or explosion. These merits entail our configured cathodes with high tap density (1.54 g cm−3), less electrolyte usage, good security for flame retardance, and decent Li‐storage behaviors. With lean and LiNO3‐free electrolyte, packed full cells exhibit excellent redox kinetics, suppressed LiPS shuttling, and excellent cyclability. This may trigger great research enthusiasm in rational design of low‐carbon and safer S cathodes.