LAUSR

Microporous carbons with high surface areas were prepared for supercapacitor electrode materials by using potato as carbon source and KOH as activating agent under different processing conditions. The nitrogen adsorption-desorption isotherms show that the prepared carbons have abundant micropores. It was found that the carbonization temperature, activation temperature, and the mass ratio of the activating agent to potato have dramatic influence on the pore structure of carbons and thus the capacitive performances. The electrochemical results indicate that the sample (TC-600-800-5) carbonized at 600 °C, and then activated at 800 °C with a mass ratio of KOH to carbon of 5:1 shows the best capacitive performance. This may be due to the largest surface area (2392 m2 g−1), largest pore volume (1.00 cm3 g−1), and the largest micropores (0.70 and 1.55 nm). The highest specific capacitance achieved in this research is 337 F g−1 at 1.0 A g−1. The assembled symmetric supercapacitor has a high energy density of 13.6 Wh kg−1 at a power density of 500 W kg−1, and the capacitance can maintain 96.24% 10,000 cycles. Graphical abstract Graphical abstract