Porous and high specific surface area carbon material derived from ginkgo leaves for high-performance symmetric supercapacitors

Carbon materials have the advantages of large surface area, high conductivity and stable chemical properties, and are widely used in the field of electrochemical energy storage. However, carbon materials currently have some problems such as high cost, complicated process and poor electrochemical performance. The development of low cost, environmental friendly and high specific capacitance porous carbon materials is of great significance for large-scale production and application. In addition, renewable, low-cost biomass materials are ideal precursors for the preparation of porous carbon materials. In this work, porous carbon materials were synthesized using ginkgo leaves as carbon source and KHCO3 as activator. The effect of activator mass on the structure and composition of porous carbon was studied in detail. The results show that when 3 g activator is added, the prepared carbon material (GCK-3) has a specific surface area of up to 2640 m2 g- 1 and a rich hierarchical pore structure (including micro, medium and large pores). In addition, the carbon material retains a certain amount of the heteroatoms of the biomass itself, which can generate additional pseudocapacitance. Due to the advantages of composition and structure, GCK-3 shows good electrochemical performance and rate performance. A symmetric supercapacitor assembled from two identical GCK-3 electrodes has an energy density of 13.7 Wh kg- 1 and exhibits good cycle stability with a capacitor retention rate of 100 % after 10,000 cycles. The green and low-cost carbon source precursor, simple synthesis method and excellent electrochemical properties all indicate that ginkgo leaf derived carbon materials have great application prospects.