Exfoliated Magnesium Diboride Nanosheets as Solid Fuels

Magnesium diboride (MgB₂) has been explored as an alternative fuel to boron (B) due to its high energy density and an additive effect of magnesium (Mg) to promote B combustion. However, in the oxidation process, MgB₂ has a relatively slow reaction rate and high ignition threshold compared to other metal or metalloid fuels. The primary oxidation of MgB₂ does not occur unless it decomposes at a high temperature (830 °C), and it still has slow heterogeneous oxidation of boron following the decomposition. Recently, two-dimensional (2D) exfoliated MgB₂ nanosheets have attracted increasing attention due to their unique properties and potential applications in various fields. In this work, we present the potential of 2D exfoliated MgB₂ nanosheets as solid fuels in overcoming the challenges of MgB₂ combustion. The oxidation behavior and energetic performance of MgB₂ nanosheets are studied through materials characterization and combustion tests under slow and fast heating conditions. The results show that the MgB₂ nanosheets oxidize from a lower temperature than bulk MgB₂ under slow heating conditions as the MgB₂ nanosheets oxidize without decomposition. At fast heating rates, the MgB₂ nanosheets exhibit a lower ignition threshold, higher combustion efficiency, and faster energy release rate than other B-based fuels. This study highlights the potential of MgB₂ nanosheets as promising solid fuels with superior energetic properties.