Mechanically Produced Sub-Micro and Nano Powders of Mg and Mg/Carbon Composites as Anode Material of Primary and Secondary Mg-Air Batteries

In this work, sub-micro and nanometer sized Mg and Mg/carbon composites as anode materials of Mg-air batteries is prepared by using an innovative rotary ball mill. Characterization of the prepared samples is performed by dynamic light scattering, scanning electron microscopy, transmission electron microscopy and, X-ray diffraction techniques. The effects of milling time and amount of carbon additive are evaluated on the sizes of Mg particles in different samples, the discharge capacities and also other electrochemical performances of both primary and secondary magnesium air batteries. An aqueous solution of 2 M Magnesium Chloride and 3 M Sodium Chloride and an organic solution of 0.2 M I2 in Dimethyl Sulfoxide are used as electrolytes in primary and secondary Mg-air batteries, respectively. The Mg sample T6 with average particle size of 170 nm and the Mg/carbon composite sample T13 with average particle size of 35 nm show the highest discharge capacities in both primary (333.1 and 418.6 mA.h g-1) and secondary (354.4 and 433.9 mA.h g-1) Mg-air batteries, respectively. The cycle life test was examined on all constructed rechargeable Mg-air batteries over 30 cycles.