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

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 (similar to 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.

Automated summary

Replacing carbon materials with indium-doped tin oxide (ITO) nanoceramics as hosts in Li-S cathodes can increase electrode density, reduce electrolyte usage, improve flame retardance, and exhibit good lithium storage performance.