Graphene/carbon aerogel for high areal capacity sulfur cathode of Li-S batteries

Abstract

Lithium-sulfur batteries are promising high-energy-density devices for next-generation energy storage systems. One of the most challenging issues impeding their practical application is how to develop cost-effective thick sulfur cathode with fast kinetics. Carbon aerogels (CAs) show great potential as host for lithium-sulfur batteries, while the preparation of CAs usually requires special time-consuming drying techniques to retain their porous structure. In this work, we develop a facile method to tailor the flexible structure of the CAs by simply using NaCl, leading to a more stable porous structure that resists the collapse of pores during conventional drying process. High gravimetric and areal sulfur loading can be realized in the synthesized hierarchically porous carbon aerogel electrode. With 69 wt% and over 6 mg cm−2 sulfur loading on the cathode, the cell delivers an initial capacity of 1121 mA h g−1 and a reversible capacity of 797 mA h g−1 after 100 cycles under the current density of 0.2 C.