Carbon nanotube springs with high tensile strength and energy density

Abstract

While different energy storage systems have been developed for particular modes of usage, there is still a demand for sustainable energy storage systems that can offer both lightweight and high energy density. An alternative form of energy storage is proposed based on the elastic deformation of carbon nanotubes (CNTs). We report the continuous preparation of long CNT fibers and continuous twisting of the fibers to springs. The prepared long springs have a tensile strength of 325 MPa and/or an energy density of 42.1 J g⁻¹, both of which are higher than the counterparts previously reported in the literature. Considering their low density and high performance, these new CNT springs have great potential for applications in many areas such as automobile, aerospace, and mechanical devices.