Compressive buckling of open-ended boron nitride nanotubes in hydrogen storage applications

Abstract

Boron nitride nanotubes (BNNTs) have outstanding physical and mechanical properties and enhanced chemical stability, compared to carbon nanotubes (CNTs) and are more suitable for hydrogen storage applications. However, hydrogen storage is believed to make changes to the mechanical properties of BNNTs, hence, this work investigates the effect of hydrogen physisorption, up to 5% of system weight, on the compressive buckling strength of BNNTs using molecular dynamics simulations. After considering the effect of hydrogen storage percentages on the compressive buckling strength at room temperature, due to the temperature dependence of both hydrogen storage capacity and compressive mechanical properties of BNNTs, the effect of hydrogen storage on the temperature-dependent compressive buckling of BNNTs are also studied. Results indicate that at room temperature, hydrogen storage leads to an average 14% decrease in the buckling strength of the nanotubes, but this decrease is almost the same for different percentages and does not show a significant relation with the percent of hydrogen storage in the system. Further results reveal that increasing the temperature from 300 to 3000K leads to 15% and 13% decrease in the buckling strength of BNNTs with and without hydrogen storage, respectively, where storage of molecular hydrogen comprising 5% of system weight results in an average 10% decrease in the buckling strength, at various temperatures in this range. Characterization of the effects of hydrogen storage on the mechanical properties of open-ended boron nitride nanotubes has been performed in this paper, which can lead to practical applications of these nanotubes, especially in hydrogen storage application.