Facile fabrication of nanoporous graphene powder for high-rate lithium–sulfur batteries

Abstract

Well-designed structures constructed from graphene are excellent sulfur host matrices which can improve the electrochemical performance of lithium–sulfur (Li–S) batteries by alleviating the dissolution of polysulfide and improving the electrical conductivity of the electrode. Herein, high quality graphene powder with a nanoshell inside was successfully designed and fabricated through a simple spray-drying and Fe-catalyzed chemical vapor deposition (CVD) process. In this structure, the intrinsic interconnected graphene nanoshells afford sufficient space for accommodating the active sulfur material, provide effective entrapment for the dissolution of polysulfide and facilitate fast electron and mass transport. Benefiting from this unique architecture, a high specific discharge capacity of 400 mA h g⁻¹ with well-maintained two-step galvanostatic discharge profiles can be obtained at an ultra-high current density of 13.4 A g⁻¹.