New simple flame burning method to prepare SWNT sponges on a large scale

In a paper published in NANO, a group of researchers have developed a simple flame burning method to prepare single-walled carbon nanotube (SWNT) sponges on a large scale. The SWNT sponge has multifunctional properties and can be used in the fields of cleaning-up, sensing and energy storage.

How to prepare the lightweight and porous carbon nanotube (CNT) sponges with mass production and without high energy and time consumption?

A group of researchers have discovered a method of preparing single-walled carbon nanotube (SWNT) sponges with a 3D elastic interconnected hollow skeleton network by burning the commercial polyurethane (PU) sponges coated with SWNTs.

The PU sponge can be removed in an ethanol flame in less than 20 s, leaving sponge-like structures. Compared with previously reported chemical vapor deposition (CVD), freeze-drying method, the flame burning method used in this work has the advantages of being density controlled, low cost and suitable for large-scale production. Additionally, the advantage of sponge shape and size controlled by pretreatment of PU templates is also the most important aspect of the method, superior to other methods.

The most significant aspect of this study is that the SWNT sponges was developed by a superfast flame burning method in less than 20 s through removing PU sponge template coated with SWNTs in an ethanol flame, which has not ever been reported. The as-synthesized SWNT sponges exhibit a series of comparable properties, including high conductivity, moderate organic liquid adsorption, good elasticity and high specific capacitance. Also, the sponges could reach an ultralow density of 0.8 mg cm?3 and keep the original geometry of PU template without distortion. The high hydrophobicity endows the SWNT sponges with admirable adsorption rate and capacity for organic solvents. The sponges could not only reach a maximum compressive stress of 11,500 Pa at 80% strain, but also bear more than 1000 compression cycles at 60% strain. Further, the porous SWNT sponges used as a flexible electrode material achieves a high specific capacitance of 126.8 F g?1 and 95% capacitive retention over 10,000 cycles.