Carbon Nanotubes Derived from Yeast-Fermented Wheat Flour and Their Energy Storage Application

Worldwide growing commercial interests in applying carbon nanotubes (CNTs) in diverse applications, such as batteries, sensors, catalyst supports, thermal electronics, and high-strength composites, have dramatically expanded the demand for higher CNT production capacity. However, current CNT production is still dominated by relatively high-cost chemical vapor deposition (CVD) methods, which usually involve high temperatures, expensive catalysts, and substantial quantities of nonrenewable petroleum-derived carbon sources. Here, we report that highly dense carbon nanotubes can be derived from yeast-fermented wheat dough scaffolds via a simple, green, and sustainable activation process without using any additional catalysts or extra carbon sources. When the activated wheat dough/carbon nanotube (AWD/CNT) scaffold is used as a sulfur host to prepare cathode for lithium-sulfur (Li-S) battery, the assembled Li-S cell exhibited excellent cyclic performance, with a well-retained capacity of ∼450 mA h g^-1 even after 1500 cycles at a high charge/discharge rate of 1 C. A "self-catalysis" growth mechanism is proposed to explain the formation of the yeast-derived CNTs. Our new findings represent a paradigm shift in developing CNTs and provide a promising solution to obtain advanced renewable carbon materials from natural and abundant biomass materials for use in energy storage applications.