Acta Phys. -Chim. Sin. ›› 2010, Vol. 26 ›› Issue (09): 2397-2404.doi: 10.3866/PKU.WHXB20100845

• ELECTROCHEMISTRY • Previous Articles     Next Articles

Influence of Ball-Milling on Hydrogen Storage and Electrochemical Properties of (Ti Cr)0.497V0.42Fe0.083/30%(w) (LaRMg)(NiCoAl)3.5 Alloy Electrodes

LUO Yong-Chun1,2, ZHANG Tie-Jun1, WANG Duo1, KANG Long1   

  1. 1. College of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050, P. R. China;
    2. State Key Laboratory of Gansu Advanced Non-Ferrous Metal Materials, Lanzhou University of Technology, Lanzhou 730050, P. R. China
  • Received:2010-02-18 Revised:2010-04-27 Published:2010-09-02
  • Contact: LUO Yong-Chun E-mail:luoyc@lut.cn
  • Supported by:

    The project was supported by the Doctoral Foundation of Lanzhou University of Technology, China.

Abstract:

Changes in phase structure, hydrogen storage and electrochemical properties of the (Ti Cr)0.497V0.42Fe0.083+ 30% (w) (LaRMg)(NiCoAl)3.5 alloy after treatment by ball-milling for different time (t=0, 0.5, 1, 3, 5, 10 h) were investigated systematically. X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) showed that the particle size of the milled composite samples decreased gradually and the powder appears aggregated. The A2B7 alloy particles were uniformly dispersed and encapsulated on the surface of the V based alloy particles that were formed after increasing the ball-milling time. It was found that nanocrystalline composites were formed and partial amorphization occurred when the milling time was more than 5 h. The crystal parameter a and the cell volume V of the BCC phase structure in the composite both showed a decrease. Hydrogen storage capacity of the single V based alloy was 3.11%(w), with an increase in milling time hydrogen storage capacity of the milled composites decreased and the maximum hydrogen absorption capacity at room temperature approached 2.47%(w). Electrochemical studies showed that the electrochemical properties of the milled composite were enhanced and the maximum discharge capacity was 425.8 mAh·g-1. The cyclic stability of the composite electrode improved noticeably. After 100 charge-discharge cycles the discharge capacity retention rate C100/Cmax of the milled composite electrode was 97%, and it had a better cycle life than that of the A2B7 type alloy electrode.

Key words: V-Ti-Cr-Fe and rare earth based alloy, Modification by ball-milling, Hydrogen storage property, Electrochemical property

MSC2000: 

  • O646