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.