Porous graphene with high porosity derived from nitrogen-doped graphene aerogel for vapor adsorption and lithium–sulfur batteries

Abstract

Graphene-based aerogels have garnered significant attention due to their combined advantages derived from both graphene and aerogels. Nevertheless, a key limitation in their practical applications arises from their relatively modest specific surface area and pore volume. In this study, porous graphene materials with high porosity are synthesized through the physical and chemical activation of nitrogen-doped graphene aerogel (NGA) using carbon dioxide and KOH as activating agents. The carbon dioxide-activated NGA (CNGA) maintains the spongy aerogel structure and exhibits a hierarchical porous structure encompassing micropores, mesopores, and macropores. Notably, CNGA exhibits a high specific surface area (2030 m² g^–1) and pore volume (5.4 cm³ g^–1). Given its intriguing properties, the CNGA porous material shows exceptional adsorption capabilities for toluene (2625 mg g^–1) and methanol (2091 mg g^–1) under saturated vapor pressure conditions, making it possible to serve as an efficient gas adsorbent. Furthermore, the CNGA as a sulfur host for lithium–sulfur battery demonstrates good cycling performance, retaining a discharge specific capacity of 719.6 mA h g^–1 even after 200 cycles at a rate of 0.5 C.