Swallow-Nest-Inspired Strategy towards Ultralight Functional Multiwall-Carbon-Nanotube-Based Aerogels for Supercapacitors

Electrode materials with superior electrochemical properties are at the core of energy-conversion and storage devices such as supercapacitors. Here, an ultralight functionalized multiwall-carbon-nanotube (FMWCNT) based aerogel with swallow nest structure is fabricated by a simple and facile method, and further used as a freestanding electrode for supercapacitors. Besides, soft X-ray absorption near-edge structure measurements were performed to probe the valence bonds of the as-prepared FMWCNT aerogel, revealing the existence of chemical interactions among the atoms. More importantly, a series of experiments including cyclic voltammetry, galvanostatic charge-discharge cycling, and rate capability tests were performed to evaluate the properties of the as-prepared FMWCNT aerogel electrodes. Impressively, the specific capacitance of the electrodes was as high as 319 Fg(-1) in 0.5 M H2SO4 at a constant current density of 10 Ag-1, and no decay was observed after 2000 cycles. These superior properties can be attributed to the unique interconnected nanostructure, large specific surface area, and synergistic effect of the FMWCNT aerogel.