Potassium citrate-derived carbon nanosheets/carbon nanotubes/polyaniline ternary composite for supercapacitor electrodes

Abstract To improve the electrochemical performance of potassium citrate-derived carbon nanosheets (PC Cs), herein, bamboo-like carbon nanotubes (CNTs) are generated on PC Cs to prepare PC Cs/CNTs composite. Based on interconnected porous PC Cs/CNTs, polyaniline (PANI) is in-situ polymerized to fabricate PC Cs/CNTs/PANI ternary composite. Through adjusting the aniline concentration, the optimized PC Cs/CNTs/PANI composite is obtained at the aniline concentration of 0.4 M. The result confirms that much more N-containing groups are introduced after growing PANI on PC CS/CNTs, and the diameter of PANI-wrapped CNT is about three-time thicker than that of CNT. Served as working electrode in three-electrode system, the optimized PC Cs/CNTs/PANI composite delivers the maximum capacitance of 767 F g−1 at 1 A g−1, with a high capacitance retention of 87.5% for 5000 cycles at 5 A g−1. When assembled in asymmetric supercapacitor by using PC Cs/CNTs/PANI as positive electrode and PC Cs/CNTs as negative electrode, the device exhibits a specific capacitance of 102.5 F g−1 at 0.5 A g−1, and energy density is 56.9 Wh kg−1 at the power density of 537 W kg−1. Compared to existing carbon/PANI composites, PC Cs/CNTs/PANI composite shows an outstanding electrochemical performance, due to the tailored pore structure of PC Cs/CNTs and the high pseduocapacitance contributed by PANI wrapping layer.