Green and facile fabrication of Cu-doped carbon aerogels from sodium alginate for supercapacitors

Traditional carbon aerogels are made of resorcinol and formaldehyde. The synthesis process is cumbersome and the electrochemical performance is poor. Therefore, designing carbon aerogels with environmentally friendly raw materials, simple synthesis steps and good electrochemical performance is of great important. In this article, Cu-doped carbon aerogels (Cu-CA) were synthesized by one-step carbonization using sodium alginate (SA) as the carbon precursor. The specific surface area of the Cu-CA was 230.4 m(2)g(-1). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to obtained the microstructure of the Cu-CA. Cu nanoparticles (Cu NPs) were found to be embedded in the carbon aerogels homogeneously. The performances of the Cu-CA as supercapacitor electrode materials were investigated via cyclic voltammetry test (CV), galvanostatic charge-discharge test (GCD) and electrochemical impedance spectroscopy (EIS) using three-electrode system and the reference electrode was Hg/HgO electrode. Due to the metal-doped and unique hierarchical porous structure, the specific capacitance of the Cu-CA was up to 414.4 F g(-1) with GCD (scan rate: 0.3 mV s(-1)), and the Cu-CA electrode showed good cycling stability. The excellent electrochemical performances of the Cu-CA indicate their great potential applications in the energy storage field.