Makinde Wasiu Olakunle, Hassan Mohsen A, Semida Wael M, Pan Ying, Guan Guoqing, López-Salas Nieves, Khalil Ahmed S G
Materials Science and Engineering Program, Egypt-Japan University of Science and Technology (E-JUST) New Borg El-Arab City 21934 Alexandria Egypt.
Horticulture Department, Faculty of Agriculture, Fayoum University 63514 Fayoum Egypt.
RSC Adv. 2025 May 14;15(20):15819-15831. doi: 10.1039/d5ra01262g. eCollection 2025 May 12.
Green pea peel (GPP) is a waste, and it is abundant and available to be used for biochar synthesis. GPP-derived biochar (GP) is used vastly in wastewater treatment. Moreover, heteroatom co-doping of GP could be better than its single-doped and undoped in enhancement of active sites and conductivity, and in developing electrodes for supercapacitor applications. However, uncontrolled heteroatom co-doping clogs the pores in the biochar and stops the electrolyte from penetrating the porous structure, which results in reduced capacitance and higher resistance in the biochar. This study presented the controlled synthesis of GP, nitrogen (N)-doped biochar (NGP), and N and sulfur (S) co-doped GP (NSGP) through carbonization and chemical activation. As revealed by the characterization techniques, the synthesized GP, NGP, and NSGP are nanosheets with amorphous structures and defective structures. The specific capacitance of the NSGP-based electrode material, as determined by electrochemical characterizations, is 257.01 F g, more than the 230.22 F g and 208.78 F g of NGP and GP at 1 A g, respectively. The assembled NSGP//NSGP supercapacitor device has an 80.25 F g specific capacitance at 1 A g, an energy density of 13.87 W h kg, and a 500 W kg power density with a 99.46% capacity retention after 5000 cycles at 5 A g. It demonstrates that NSGP has better electrochemical performance than NGP and GP because of the improved active sites and conductivity.
绿豌豆皮（GPP）是一种废弃物，其产量丰富且可用于生物炭的合成。源自GPP的生物炭（GP）在废水处理中得到广泛应用。此外，GP的杂原子共掺杂在增强活性位点和导电性以及开发用于超级电容器应用的电极方面可能比其单掺杂和未掺杂情况更好。然而，不受控制的杂原子共掺杂会堵塞生物炭中的孔隙，阻止电解质渗透到多孔结构中，从而导致生物炭的电容降低和电阻升高。本研究通过碳化和化学活化展示了GP、氮（N）掺杂生物炭（NGP）以及氮和硫（S）共掺杂GP（NSGP）的可控合成。表征技术表明，合成的GP、NGP和NSGP是具有无定形结构和缺陷结构的纳米片。通过电化学表征确定，基于NSGP的电极材料在1 A g时的比电容为257.01 F g，分别高于NGP和GP在1 A g时的230.22 F g和208.78 F g。组装的NSGP//NSGP超级电容器装置在1 A g时的比电容为80.25 F g，能量密度为13.87 W h kg，功率密度为500 W kg，在5 A g下经过5000次循环后容量保持率为99.46%。这表明由于活性位点和导电性的改善，NSGP具有比NGP和GP更好的电化学性能。
