High performance Li-S batteries using cathodes produced with carbons derived from physically activated recycled surgical masks

Abstract

Activated carbon derived from recycled, discarded surgical masks has been used as a sulfur host for lithium-sulfur (Li-S) batteries. The activation process was carried out using physical methods, which are simpler and cleaner than chemical approaches. Two activating agents, CO2 and steam, were employed, with steam resulting in somewhat higher BET surface and pore volume, as well as better electrochemical performance, leading to a greater number of tests being carried out on this material. When mixed with sulfur (∼70%), the steam-activated carbon demonstrated outstanding electrochemical properties, including good rate capability (an average capacity ranging from 970 mAh g−1 at 0.1C to 360 mAh g−1 at 2C), high reversible capacity and impressive cycling stability (average capacity ∼850 mAh g−1 at 0.3C after 400 cycles). It also showed good areal capacity values and high lithium-ion diffusion coefficients (DLi+). This study underscores the use of physical activation as a simple, clean, easy, and efficient alternative to improve the performance of carbons in high performance Li-S batteries.