Fabrication of high-surface-area, SiO2 supported polyimide carbon aerogel microspheres: electrochemical application

Abstract

A series of polyimide (PI)/SiO _2 aerogel microspheres were prepared by using polyamide acid salt and hydrolyzed tetraethyl orthosilicate based on the reverse-phase emulsion method. Then, PI/SiO _2 aerogel microspheres were carbonized and etched to obtain carbon aerogel microspheres (CAMs). Scanning electron microscope, transmission electron microscope and nitrogen isothermal adsorption were used to characterize the micro-morphology and pore structure of the microspheres; and electrochemical workstation was used to test the electrochemical performance of the CAMs. The results showed that CAMs with different pore structures and specific surface area were obtained by adjusting the content of SiO _2 . Highest specific surface area of 1166.9 m ^2 g ^−1 and a total pore volume of 1.2369 cm ^3 g ^−1 were achieved at a SiO _2 content of 50%. When used as the electrode materials for supercapacitors, these CAMs demonstrated a maximum specific capacitance of 125.1 F g ^−1 in a three-electrode system and a maximum capacitance of 53.3% at 30 A g ^−1 . This article provides a new strategy for the preparation of CAMs with high specific surface area by using linear PI precursor and SiO _2 support skeleton.

Keywords

• carbon aerogel microspheres
• polyimide
• SiO2
• reverse emulsion
• supercapacitors