Dry Carbothermal Reaction-Enabled Ultra-Dense Nanoparticle Coatings for High-Performance Li-S Batteries

Abstract

Electrocatalysts are crucial for facilitating the sluggish conversion between S and sulfide in Li-S batteries. Despite recent exploration of advanced materials, there remains a significant gap in the morphology design rationale oriented towards practical operation conditions. In this study, we introduce a dry process based on the carbothermal reaction of oxides to achieve nanoparticle (NP) electrocatalyst coatings. This process enables us to produce ultra-high-density NPs with several tens of particles per 100 nm x 100 nm area. We unveil that this high coating density boosts the conversion kinetics by dominating a solution-phase disproportionation reaction, thereby promoting the growth of non-passivating particulate sulfide. With this NP-coated cathode, we achieve excellent kinetic performance, maintaining 53% of cell capacity retention even with a 50-fold increase in C-rate, and exhibiting only a 0.04% capacity decay per cycle over 300 cycles at 10 C. Remarkably, our cathode achieves an initial areal capacity of 7.51 mAh cm-2 in a full cell, significantly outperforming cells reported in previous studies as well as conventional Li-ion batteries.

Keywords: nanoparticle electrocatalysts, Carbothermal reaction, high coating density, Conversion kinetics, Li-S battery performance