Preparation of nitrogen-doped porous carbon from pyrolysis of light bio-oil pretreated poplar powder and its electrochemical performance

Biomass are widely used for the preparation of porous carbon materials (PCM). Therefore, there is considerable interest in how to obtain PCM with excellent electrochemical performance from biomass. Effective pretreatment methods can significantly improve the electrochemical performance of PCM. However, the low nitrogen content in most biomass limits its further application as electrode materials. Thus, this paper proposes a new method for preparing nitrogen-doped PCM. Nitrogen-doped PCM with outstanding performance were synthesized from poplar powder pretreated by light bio-oil in a ZnCl2/urea system. The findings indicate that adding urea notably enhanced nitrogen content in PCM surface, improving its electrochemical performance. When the mass ratio of ZnCl2, pretreated poplar powder and urea is 2:1:1 (PZN(1)-500), the nitrogen content of prepared PCM is 9.46 %. The maximum specific capacitance reaches 382.7 F/g at 0.5 A/g. Furthermore, the assembled symmetrical PZN(1)-500 supercapacitor possessed the energy density of 9.16 Wh kg(-1) at 125 W kg(-1) with the capacitance retention of 92.65 % after 10,000 cycles. The preparation strategy of nitrogen-doped PCM proposed in this study is helpful for the further development of supercapacitors and the high-value utilization of biomass.