Composite Anodes for Secondary Magnesium Ion Batteries Prepared via Electrodeposition of Nanostructured Bismuth on Carbon Nanotube Substrates

Magnesium-ion batteries are attractive in part due to the high environmental abundance and low cost of magnesium metal. Anode materialsotherthanMgmetalcanprovideaccesstonewelectrochemistriesinnon-corrosiveMg2+ electrolytes.Acyclicvoltammetric method for the preparation of bismuth (Bi) based anodes was developed by systematically exploring electrodeposition using a quartz crystal microbalance. Controlled deposition of Bi on carbon nanotubes substrates could be achieved, enabling the first electrochemical investigation of bismuth-carbon nanotube (Bi-CNT) composite electrodes. Quasi-reversible Mg electrochemistry of Bi-CNT composite electrodes in non-corrosive magnesium-based electrolyte was demonstrated, with an initial delivered capacity exceeding 180 mAh/g. While the initial capacities were high, significant capacity decreases were observed with repeated cycling,