Hollow carbon spheres with artificial surface openings as highly effective supercapacitor electrodes

Abstract

A novel kind of hollow carbon spheres with artificial surface openings is fabricated as highly effective supercapacitor electrode. This kind of carbon sphere possesses typical hierarchical mesoporous structure with surface area of 670.0 m2 g−1, much higher than that of the conventional hollow carbon spheres and solid carbon spheres. The electrochemical performance of the prepared hollow carbon spheres with surface openings, hollow carbon spheres and solid carbon spheres electrode are evaluated in acidic aqueous electrolyte. The hollow carbon sphere with surface openings electrode shows the optimal capacitive performance due to the specific surface openings and hierarchical mesoporous structure which can provide a large ion-accessible surface area and a loose channel for the electrolyte ions to diffuse into the internal of the spheres, making the internal charge storage sites work more effectively. The hollow carbon spheres with surface openings electrode achieves a remarkable specific capacitance of 272.2 F g−1, much higher than that of the hollow carbon spheres and solid carbon spheres. Besides, the hollow carbon spheres with surface openings preserves 96.9% of its initial capacitance after 10000 charge-discharge cycles, suggesting a perfect cycle life.