Magnesium microspheres and nanospheres: Morphology-controlled synthesis and application in Mg/MnO2 batteries

Abstract

In this paper, we report on the morphology-controlled synthesis of magnesium micro/nanospheres and their electrochemical performance as the anode of primary Mg/MnO 2 batteries. Mg micro/nanoscale materials with controllable shapes have been prepared via a conventional vapor-transport method under an inert atmosphere by adjusting the deposition temperatures. Extensive analysis techniques including SEM, XRD, TEM/HRTEM, and Brunauer Emmett Teller (BET) were carried out to characterize the as-obtained samples. The results show that the Mg samples are microspheres or micro/nanospheres with specific surface areas of 0.61 1.92 m 2 /g. The electrochemical properties of the as-prepared Mg and commercial Mg powders were further studied in terms of their linear sweep voltammograms, impedance spectra, and discharge capability. By comparing the performance of different inhibitors in electrolytes, it was found that NaNO 2 (2.6 mol/L) as an inhibitor in the Mg(NO 3 ) 2 (2.6 mol/L) electrolyte affords a Mg electrode with high current density and low corrosion rate. In particular, the Mg sample consisting of microspheres with a diameter of 1.5 3.0 μm and nanospheres with a diameter of 50 150 nm exhibited superior electrode properties including negative initial potential ( 1.08 V), high current density (163 mA/cm 2 ), low apparent activation energy (5.1 kJ/mol), and high discharge specifi c capacity (784 mAh/g). The mixture of Mg nanospheres and microspheres is promising for application in primary Mg/MnO 2 batteries because of the suffi cient contact with the electrolyte and greatly reduced charge transfer impedance and polarization.

Ultralong monoclinic ZnV2O6 nanowires: their shape-controlled synthesis, new growth mechanism, and highly reversible lithium storage in lithium-ion batteries

“…A fluffy wool-like product emerged near the inner wall of the Teflon vessel was collected, centrifuged, washed with water and absolute ethanol several times to remove the byproduct, and then dried at 80 uC for 12 h for further analysis. 35,36 For comparison, microscale bulk counterparts with layered structures were fabricated through the solid-state reaction method via calcined ZnO and V 2 O 5 powders at 600 uC for 12 h in air atmosphere ( Fig. S1 in the ESI{).…”

Mg2Al3, a complex and disordered intermetallic compound as anode material for metal-air batteries

“…This is in agreement with the calculated density which is found about 60 %. Definitely, sample surface displays roughness which could support some heterogeneity in the corrosion phenomena (preferential domains, intergranular attack, …) and have some influence on the anode performances as reported for Mg samples of various controlled morphologies [22,23].…”

“…In search of the improvement of electrochemical performances of metal-air batteries, several Mg-based materials have been tested as anodes; most of them are multiphase or composite materials [18][19][20][21]. On the other hand, morphology effects (nano, meso…) of the anode materials have been reported [22,23]. Rechargeable systems implying reversible reactions remain a facing challenge, but the Mg-air primary batteries, mechanically "refuelable," can still be improved through investigation of new electrode materials able to replace Mg [14].…”

Enhancement of Discharge Capacity of Mg/MnO2 Primary Cell with Nano-MnO2-Graphene as Cathode

“…Graphene is widely synthesized using different methods mainly to enhance its size-dependent properties. In general, methods such as epitaxial growth by ultra-high vacuum graphitization [11][12][13], chemical vapor deposition [14][15][16], solvothermal process [17,18], solgels [19], and ion exchange and hydrothermal reduction [20,21] are used to obtain graphene sheet. Among these methods, electrochemical and chemical reduction methods are widely used to synthesize graphene because of their lower cost and environment friendly nature.…”