Preparation and Characterization of Porous Carbon from Mixed Leaves for High‐Performance Supercapacitors.

Main observation and conclusion: With the increasing demand of sustainable and eco‐friendly resources, it is very attractive to use waste leaves for activated carbon (AC) preparation that can be used in supercapacitors. Considering the practically collected leaves are commonly in mixed nature, and extra efforts are needed to sort these mixtures, we here report the first preparation of AC using mixed leaves from different plants, including Platanus acerifolia (PA), Firmiana platanifolia (FP) and Pistia stratiotes (PS), and compared the results with single leaves‐derived AC materials. These leave‐derived AC samples were characterized with FESEM, EDS, FTIR and Raman spectroscopy, and electrochemical tests. The AC derived from mixed leaves (PA3FP1PS2AC) showed a good specific capacitance of 246 F·g−1 at 1 A·g−1 in aqueous 3 mol·L–1 KOH. This sample further showed the largest specific capacitance of 201 F·g−1 at 5 A·g−1, as compared with the non‐mixed AC samples, and a good stability of 100.0% capacitance retention over 1000 cycles. Utilizing mixed leaves for AC preparation is not only demonstrated to be a promising approach of low cost and high‐performance AC production for supercapacitor applications, but may also help environmental protection by reducing the invasive species problem. [ABSTRACT FROM AUTHOR]