Microdomain sulfur-impregnated CeO2-coated CNT particles for high-performance Li-S batteries

Abstract

Li-S cathode loaded with microdomain sulfur is preferred because of its high utilization of sulfur during charging and discharging. Encapsulating sulfur in porous carbon has often been used to form microdomain sulfur, but is limited by the charge/ion diffusion resistance in the pores. Here we demonstrate the formation of microdomain sulfur in the open pore CNT assembly. We obtain microdomain sulfur on CNTs coated with CeO2 nanoparticles, explained by local spontaneous dewetting. Our microdomain sulfur-deposited CNT-based electrodes perform fast kinetics of sulfur transformation and high utilization of sulfur, especially at high C-rate and high current density conditions. Li-S battery cells with our electrodes achieve excellent long-term stability under high C-rate (capacity reduction of 0.044% per cycle up to 300 cycles at 2C), and high capacity even with high sulfur loading (an areal capacity of 5.6 mAh/cm2). Our approach presents facile and low-cost route to designing high performance Li-S batteries.