Electrochemical and electronic properties of nanocrystalline Mg-based hydrogen storage materials

摘要

Nanocrystalline metal hydrides are a new class of materials in which outstanding performance may be obtained by proper engineering of the microstructure. In this work, we have studied experimentally the structure, electrochemical and electronic properties of nanocrystalline Mg_2Cu and Mg_2Ni alloys. These materials were prepared by mechanical alloying (MA). In the nanocrystalline Mg_2Cu powder, discharge capacity up to 26mAhg~(-1) was measured. It was found that nickel substituting copper in Mg_2Cu_(1-x)Ni_x alloy greatly improved the discharge capacity of studied material. In nanocrystalline Mg_2Ni powder, discharge capacities up to 100 mAh g~(-1) were measured. Finally, the electronic properties of nanocrystalline Mg-based alloys are compared to those of polycrystalline samples. The studies show, that electrochemical properties of Mg-based powders are the function of the microstructure and the chemical composition and of used electrode materials.