Ionothermal synthesis of graphene-based microporous carbon for lithium–sulfur batteries

Abstract

Designing a rational accommodating host for sulfur is in great demand for the commercial application of lithium–sulfur batteries. Herein, a 2D graphene-based microporous carbon substrate (I-GPC) with a high conductivity and diverse porous structure was designed via an ionothermal method combined with an activation process. The resultant I-GPC has a specific area as high as 1740.1 m² g⁻¹ and a hierarchical microporous structure consisting of both smaller micropores (<0.69 nm) and larger micropores (0.8 and 1.2 nm). The S/I-GPC composite presents an excellent electrochemical performance with a high initial discharge capacity up to 1510 mA h g⁻¹ at 0.1C and an impressive cycling stability of 625.8 mA h g⁻¹ after 150 cycles at 1C. The remarkable electrochemical performances are primarily attributed to the diverse microporous structure of I-GPC with high conductivity. The ionothermal method and rational design of the carbon material provide us with new opportunities for the development of other energy storage systems.