Synthesis of ultra-thin graphene-like nanosheets from lignin based on evaporation induced self-assembly for supercapacitors

Graphene-like carbon materials are widely used in power devices due to their excellent structural characteristics. In this study, ultra-thin graphene-like nanosheets (LGLNs) with rich surface wrinkles were prepared by classical evaporation induced self-assembly (EISA) using lignin biomass as carbon precursor, followed by chemical activation with KHCO3. The obtained LGLN900 material calcined at 900 °C had a thickness of ca. 3 nm, a large specific surface area of 2886 m2 g-1 with a high specific pore volume of 2.10 cm3 g-1. In addition, a large number of wrinkles on the surface of LGLN900 endows its effective compression resistance. When the LGLN900 material was used as electrode material of supercapacitor, a high specific capacitance of 388 F g-1 was obtained at 0.2 A g-1 current density in 6 M KOH aqueous solution, and 269 F g-1 specific capacitance could be at remained at 40 A g-1. The supercapacitor assembled with LGLN900 afforded a specific energy density of (11.0-13.7) Wh kg-1 at a power density of (128.8-6465) W kg-1. This work provides a facile and green strategy for the synthesis of highly wrinkled ultra-thin graphene-like nanosheets from sustainable biomass resources, which should have wide applications in adsorption, catalysis and energy storage.