Nitrogen-doped porous carbon derived from cross-cutting bamboo for high-performance supercapacitors by one-pot ball milling method

In this work, Nitrogen-doped cross-cut KOH-activated porous carbon (NCKC) was obtained through a simple and effective fabrication process. Cross-cut bamboo, KOH, and urea are mixed through a one-pot ball milling strategy. The obtained sample (NCKC) has a high specific capacitance in the three-electrode test (367 F·g−1 at 0.2 A· g−1), and maintains a satisfactory specific capacitance of 183 F·g−1 at a high current of 50 A·g−1. Moreover, an aqueous supercapacitor based on NCKC with 1 M Na2SO4 as the electrolyte can provide an outstanding specific energy of 31.1 W h kg−1 with a specific power of 200 W·kg−1, without any noticeable reduction in capacity even after 40,000 cycles. This is attributed to the fact that NCKC has an abundant hierarchical pore structure. The cross-cutting process can shorten natural pores origin from bamboo native structures, and facilitate hydrophilicity in the resulting porous carbon. The results reveal that the synergistic effect of cross-cutting process, ball milling, and N-doping in carbon enhanced the electrochemical performance of carbon remarkably. The results show such one-pot ball milling method simplifies the preparation process and is of great interest for the innovation and application of high-performance electrode materials.