Storing elastic energy in carbon nanotubes

• Published in: Journal of micromechanics and microengineering 2009-09, Vol.19 (9), p.094015-094015 (5)
• Main Authors: Hill, F A, Havel, T F, Hart, A J, Livermore, C
• Format: Article
• Language: English
• Subjects: Applied sciences; Cross-disciplinary physics: materials science; rheology; Electronics; Exact sciences and technology; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Materials science; Mechanical engineering. Machine design; Mechanical instruments, equipment and techniques; Microelectronic fabrication (materials and surfaces technology); Micromechanical devices and systems; Nanoscale materials and structures: fabrication and characterization; Physics; Precision engineering, watch making; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
• ISSN: 0960-1317; 1361-6439
• DOI: 10.1088/0960-1317/19/9/094015

The potential performance of carbon nanotubes (CNTs) as springs for elastic energy storage is evaluated. Models are used to determine an upper bound on the energy density that can be stored in defect-free individual CNTs and in assemblies of such CNTs. The models reveal that optimal energy density may be achieved in small-diameter single-walled CNTs loaded in tension, with a maximum theoretical energy density for CNT groupings of 7.8 X 106 kJ m-3. Millimeter-scale CNT springs are constructed using 3 mm tall forests of multi-walled CNTs as the starting material, and tensile tests are performed to measure the springs'stiffness, strength and elastic properties. The measured strain energy density of these continuous CNT fibers is comparable to the energy density of steel springs.