Phase Transformation of Amorphous to Crystalline of Multiwall Carbon Nanotubes by Shock Waves

Abstract

It has been a fascinating journey for the researchers to explore and understand the phase-transition behavior of materials under shock-wave-loaded condition as it has attained the status of being one of the prominent research topics in recent years due to its technological predominance so that it is imperative to understand the behavior of materials under high pressure and temperature. For the present investigation, multiwall carbon nanotubes (MWCNTs) are preferred over the other materials for shock wave impact study because MWCNTs are one of the most important as well as technologically interesting materials. However, despite many attempts over the years, the study of phase transition of materials under high-pressure and -temperature conditions continues to be a challenging task and its implications with respect to the applications to date have emerged as an ongoing debatable area. In this line, we have succeeded in tracking the phase-transition behavior of MWCNTs from amorphous-to-crystalline transition (ACT) influenced by the dynamic impact of shock waves with which experimental analyses have been performed and the details are presented. The data obtained from X-ray diffraction (XRD), Raman analysis, transmission electron microscopy (TEM), and selected area electron diffraction (SAED) reveal the formation of crystalline CNTs at 300 shock pulse-loaded condition. Due to the growing demand of industrial requirements for crystalline CNTs in energy storage applications, the samples have been subjected to the investigation of their electrochemical charge storage performances so as to ensure their utilization. Interestingly, the shock-loaded samples show substantial improvement in the electrochemical properties such that the maximum value of specific capacitance for the control 150 and 300 shocks-loaded CNTs are found to be 196, 215, and 294 F g-1, respectively.