Heteroatom-doped husk of physalis peruviana derived carbon materials for supercapacitor applications

This study compares the effects of K 2 CO 3 and KOH on the preparation of porous carbon materials derived from the calyx husk of Physalis peruviana. Using the calyx husk of Physalis peruviana as the precursor, a series of porous carbon materials (PPCPC- x–y , PPCPC stands for porous carbon derived from the calyx husk of Physalis peruviana, where “x” represents the varying ratio of activator addition, and “y” represents the different activation temperatures) were prepared through carbonization combined with K 2 CO 3 . Experiments revealed that PPCPC-2–700 exhibits exceptional performance, characterized by abundant pore structure, high surface heteroatom content (N/O), high specific capacitance (311.3 F g −1 ), and excellent rate capability (capacitance retention of 81.0%). Compared to KOH, K 2 CO 3 offers a gentler activation process, requires less activator, operates at a lower temperature, thereby simplifying the preparation procedure and reducing the preparation time. The symmetric supercapacitor assembled from the porous carbon material activated by potassium carbonate demonstrates a high voltage window of 2.0 V in 1 M Na 2 SO 4 electrolyte and achieves a high energy density of 24.37 Wh kg −1 at a power density of 500 W kg −1 . Furthermore, this supercapacitor exhibits remarkable cycle stability in alkaline electrolyte, with a capacitance retention rate close to 98% after 12,000 charge–discharge cycles. In summary, K 2 CO 3 as an activator for the preparation of porous carbon materials exhibits significant advantages, not only facilitating a simple and efficient preparation process but also yielding materials with immense potential for application in the field of electrochemical energy storage.