Abstract:

To obtain two-dimensional carbon materials with low cost and high performance, lignin-bosed carbon nanosheet was prepared using sodium lignosulfonate as carbon sources and boron acid as template followed by solution mixing, high temperature carbonization and refluxing with boiling water. The carbon nanosheets obtained with m(boron acid):m(sodium lignosulfonate)=1:1, 5:1 and 10:1 were marked as SLB-1, SLB-5 and SLB-10. The morphology of sample was characterized by SEM and TEM. XRD, XPS and Raman were used to demonstrate its constituent, structure and property. The electrochemical performance of carbon nanosheet was tested by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS) measurements. The results revealed that the sample SLB-5 exhibited well-developed teo-dimensional lamellar structure. The thickness of the carbon nanosheed could be regulated by the mass ratio of boron acid and sodium lignosulfonate. SLB-5 presented somewhat graphitic structure, the template was completely removed and the content of oxygen was 16.63%. The capacitance of SLB-5 could reach 350.79 F/g at 1 A/g, which could also maintain almost 79.95% as the current density increased to 10 A/g. After 5 000 cycles, endurance test at 5 A/g, its capacitance could still retain 90%.

Key words: carbon nanosheet, lignin, template method, supercapacitor