Single Atom-Particle Tandem Catalysis Enables Enhanced Desolvation Kinetics for Low-Temperature Li-S Batteries

Abstract

The commercial implementation of lithium-sulfur (Li-S) batteries is plagued by the sluggish kinetics of interfacial Li(solvent)x+ desolvation and successive redox conversions of sulfur species, exhibiting high tandem barriers. Herein, the tandem catalyst consisted of single Fe atom and Fe3C nanoparticles on porous carbon sheet (SAPTC@PCS) is initially proposed and developed. As illustrated in theoretical simulation, the neighboring Fe3C further tunes the electronic density and affects related coordination structure of atomically distributed iron for reinforcing catalytic efficiency. The as-prepared SAPTC@PCS facilitates the dissociation of Li(solvent)x+ to release more isolated Li+ to participate in the subsequent polysulfide redox conversions by decreasing the desolvation/diffusion barriers, as revealed by in-situ Raman, time-of-flight second ion mass spectroscopy, electronic microscope and X-ray measurements. Consequently, the cell with SAPTC@PCS delivers a high capacity-retention over 1000 cycles and high rate up to 3 C. Impressively, under the practical mass loading of 6 mg cm−2, the cell stabilizes the capacity of 4.59 mAh cm−2 after 90 cycles, and a desirable capacity of 804.8 mAh g−1 after 100 cycles is achieved even being exposed to low temperature of 0 °C, demonstrating the feasibility of single atom-particle catalysts for tandem catalysis in Li-S batteries.