Molybdenum dioxide hollow microspheres for cathode material in rechargeable hybrid battery using magnesium anode

A new type of hybrid battery has been assembled with magnesium metal anode, hollow MoO 2 microsphere cathode, and dual-salt electrolyte containing Mg 2+ and Li + ions. This kind of hybrid battery not only avoids metallic dendrite formation, which occurs in rechargeable lithium battery, but also ensures high-capacity intercalation reaction in the cathode, which is still a bottleneck for rechargeable magnesium battery. It is found that the morphology of MoO 2 electrode has a great effect on its electrochemical performance. The hollow MoO 2 microsphere cathode delivers an initial discharge capacity of 217.2 mAh g −1 with the coulombic efficiency of ca. 88 %. In the following cycles, its coulombic efficiency reaches nearly 100 %. In contrast, MoO 2 solid particles with a size of 1–10 μm exhibit a capacity less than 50 mAh g −1 . Inductively coupled plasma (ICP) analysis reveals that both of Mg 2+ and Li + ions take part in the cathode intercalation reaction.