Design of high specific surface area N-doped carbon aerogels via a microwave reduction method

Abstract

Improving the specific capacitance of carbon aerogels in supercapacitors and maintaining their high specific surface area remained an important challenge. Here, we prepared resorcinol–phloroglucinol–formaldehyde carbon aerogels reduced with hydrazine hydrate by a microwave method. The effects of the amount of hydrazine hydrate and the time of microwave reaction on the electrochemical performance of carbon aerogels were investigated. The reductive carbon aerogels were characterized by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The XPS spectra of reductive carbon aerogels indicated a presence of four nitrogen N1s groups, three oxygen O1s groups and six carbon C1s groups in the deconvoluted spectra. Surface area analysis and electrochemical performance were also investigated. The results showed that the specific surface area of the N-doped carbon aerogels could be as high as 803 m2 g−1. According to the electrochemical testing results, the specific capacitance of the N-doped carbon aerogels significantly increased and reached 219 F g−1 at a current density of 1.5 A g−1 compared to the pristine carbon aerogels. The optimal dosage and time of hydrazine hydrate was 20.6 mol L−1 for 25 min. The N-doped carbon aerogels electrode exhibited excellent reversibility with a cycling efficiency of 93.6% after 10000 cycles.