Effects of binder content on potato starch-derived porous carbon microspheres for high-performance supercapacitors

Potato starch-based carbon microspheres (PCMs) have successfully synthesized from potato starch by a simple strategy based on (NH4)2HPO4 and KOH activation. The PCMs presents a large specific surface area (SSA) of 2048 m2 g−1. The electrochemical behaviors of the PCMs with different binder content in 6 mol L−1 KOH were studied by impedance spectroscopy, cyclic voltammetry (CV), and galvanostatic charge-discharge (GCD). The results show that PCMs-85 (the binder content is 5 wt%) has a small equivalent series resistance (ESR), high specific capacitance, compacted density, and areal density. PCMs-85 exhibited good cycling durability of 100 % after 10,000 cycles at 1 A g−1 and delivered an energy density of 6.35 Wh L−1 and a volume power density of 167.38 W L−1. The corresponding capacitive performances of PCM-85-based symmetrical two-electrode supercapacitors are investigated in 6 mol L−1 KOH, 1 mol L−1 Na2SO4 and 1 mol L−1 TEA.BF4/AN electrolyte. The PCMs supercapacitor with 6 mol L−1 KOH electrolyte exhibits a mass-specific capacitance of 172 F g−1 with volumetric capacitances of 145 F cm−3 at 1 A g−1.