Acta Phys. -Chim. Sin. ›› 2013, Vol. 29 ›› Issue (08): 1804-1808.doi: 10.3866/PKU.WHXB201306061

• PHYSICAL CHEMISTRY OF MATERIALS • Previous Articles     Next Articles

Influence of KH on Reversible Dehydriding Performance of Na-Al-H Complex Hydride

WANG Shun-Kui1, LI Zhi-Jie2, XIAO Xue-Zhang1, FAN Xiu-Lin1, CHEN Zhi-Wen1, LI Shou-Quan1, GE Hong-Wei1, CHEN Li-Xin1   

  1. 1 Key Laboratory of Advanced Materials and Applications for Batteries of Zhejiang Province, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, P. R. China;
    2 College of Gansu Vocational Technology, Tianshui 741025, Gansu Province, P. R. China
  • Received:2013-04-18 Revised:2013-06-06 Published:2013-07-09
  • Contact: XIAO Xue-Zhang, CHEN Li-Xin E-mail:xzxiao@zju.edu.cn; lxchen@zju.edu.cn
  • Supported by:

    The project was supported by the National Key Basic Research Program of China (973) (2010CB631304), National Natural Science Foundation of China(51001090, 51171173), China Postdoctoral Science Foundation (20090262, 2012M521167), and Key Science & Technology Innovation Team of Zhejiang Province, China (2010R50013).

Abstract:

The Na-Al-H complex hydride was prepared by reactive ball milling (NaH/Al+CeCl3) and (NaH/Al+CeCl3/yKH) (y=0.02, 0.04) composites under a hydrogen pressure of 3 MPa at room temperature, using NaH and Al powder as raw materials, as well as 2% (molar fraction) CeCl3 and 2% CeCl3/y% KH (y=0.02, 0.04) as dopant, respectively. The de-/hydrogenation properties show that the addition of KH can effectively improve the dehydrogenation kinetics of second decomposition step for Na-Al-H system. The (NaH/Al+CeCl3/0.02KH) composite can complete dehydrogenation process within 20 min at 170℃, with good de-/hydrogenation cycling performance at relatively low temperature (100-140℃). Calculation by Kissenger method shows that the addition of KH could decrease the apparent activation energy of second decomposition step for Na-Al-H system, resulting in the decrease of desorption peak temperatures. Phase structure analysis shows that the enhanced second step dehydrogenation kinetics of Na-Al-H composite system is mainly ascribed to the lattice volume expansion of Na3AlH6 resulted from the addition of KH.

Key words: Complex hydride, NaAlH4, KH, CeCl3, Dehydrogenation kinetics

MSC2000: 

  • O643