Insights into the electrochemical performances of Bi anodes for Mg ion batteries using 25Mg solid state NMR spectroscopy.

Bi nanowires as anode materials for Mg ion batteries exhibit excellent electrochemical behaviour, forming Mg3Bi2; this is in part ascribed to the rapid Mg mobility between the two Mg sites of Mg3Bi2, as revealed by the 25Mg NMR spectra of Mg3Bi2 formed electrochemically and via ball-milling. A mechanism involving hops into vacant Mg sites is proposed.