Papers by Keyword: Mg₂Ni-Type Electrode Alloy

Abstract: Mg2Ni-type Mg20Ni10-xMx (M=Cu, Co; x=0, 1, 2, 3, 4) electrode alloys with nanocrystalline and amorphous structure were synthesized by melt-spinning technique. The microstructures of the as-spun alloys were characterized by XRD, SEM and HRTEM. The electrochemical hydrogen storage properties of the experimental alloys were measured. The obtained results show that the as-spun (M=Cu) alloys hold an entire nanocrystalline structure, whereas the as-spun (M=Co) alloys display a nanocrystalline and amorphous structure, confirming that the substitution of Co for Ni facilitates the glass formation in the Mg2Ni-type alloy. Furthermore, such substitution results in the formation of secondary phases Mg2Cu and MgCo2 instead of changing the major phase of Mg2Ni. The substitution of M (M=Cu, Co) for Ni markedly improves the electrochemical performances of the alloys, involving the discharge capacity and the cycle stability as well as the high rate discharge ability.

Abstract: The electrode alloys (Mg_1-xZr_x)₂Ni (x = 0, 0.3) were prepared by mechanical alloying (MA). Mg in the alloy was partially substituted by Zr in order to improve the electrochemical hydrogen storage characteristics of the Mg₂Ni-type alloy. The effects of substituting Mg with Zr as well as milling duration on the microstructures and electrochemical performances of the alloys were investigated in detail. The results showed that the substitution of Zr facilitates the formation of amorphous Mg₂Ni-type phase. The electrochemical measurement indicated that the substitution of Zr significantly enhances the discharge capacity and cycle stability of the alloys, and it markedly improved the discharge potential characteristic of the alloys. For a fixed alloy, the electrochemical performances, including the cycle stability and the discharge voltage characteristic as well as discharge capacity, of the alloys were markedly improved with prolonging of the ball-milling duration.