Plasma-processed homogeneous magnesium hydride/carbon nanocomposites for highly stable lithium storage

Magnesium hydride (MgH2) is a high-capacity anode material for lithium ion batteries, which suffers from poor cycling stability. In this study, we describe a thermal plasma-based approach to prepare homogeneous MgH2/C nanocomposites with very high cycling stability. In this process, magnesium evaporation is coupled with carbon generation from the plasma decomposition of acetylene, leading to a homogeneous Mg/C nanocomposite, which can be easily converted to MgH2/C by hydrogenation. The MgH2/C nanocomposite achieves a high reversible capacity of up to 620 mAh.g(-1) after 1,000 cycles with an ultralow decay rate of only 0.0036% per cycle, which represents a significantly improved performance compared to previous results.