Synthesis of nonstoichiometric amorphous Mg-based alloy electrodes by mechanical milling

Nonstoichiometric amorphous Mg-Ni and Mg-Ni-V alloys were synthesized by mechanical milling the crystalline Mg2Ni alloy with Ni and/or V powders. All the nonstoichiometric amorphous Mg-based alloys result in Mg-based alloy electrodes with very high discharge capacities by comparison with crystalline Mg2Ni alloys. The results indicate that nonstoichiometric amorphous Mg-based alloys can be obtained either by increasing the Ni content, adding a range of other elements, or both, using a mechanical milling method. The nonstoichiometric Mg-based alloy electrodes studied have shown improved initial discharge capacities compared with the stoichiometric amorphous MgNi alloy. These results describe a method of achieving better Mg-based alloy electrodes with high discharge capacities and improved cycle life. The method enables a larger composition range to be achieved with a range of vanadium additions

An anode material with pervoskite structure for rechargeable Li-ion batteries

A conductive ceramic, barium metaplumbate (BaPbO3), has been synthesized by solid-state reactions for use as an anode in lithium-ion batteries. The electrochemical characteristics of the electrode were tested in ethylene and diethyl carbonate (EC-DEC) solutions of LiPF6 versus Li metal in test cells. During cycling, the material showed voltage plateaus between 0.2 V and 0.6 V versus Li, demonstrated a gravimetric discharge capacity of about 110 mAh g-1 and a volumetric capacity of 960 mAh cm-3. Two phases, BaPbO3 and PbO, were found in compositions containing excess PbO. The free PbO in the fired bodies was found in the experiment to react with the lithium and form a new compound, probably a Pb-Li alloy, which was unstable and brought an intensive capacity fading. A single phase, BaPbO3, which was obtained by increasing the calcining temperature and the partial pressure of O2 in the ambient air, presented an unproved capacity and a stable pervoskite structure. The results from cyclic voltammograms suggest that the insertion and de-insertion of Li ions proceed in the voltage range from 0.01 to 1.2 V versus Li/ Li+