Electrochemical hydrogen storage properties of MgAlMnNi quaternary alloys. (29th March 2019)

• Record Type: Journal Article
• Authors: Ding, Yongjia; Zhu, Yunfeng; Zhang, Yao; Zhang, Jiguang; Liu, Yana; Wang, Taimiao; Fang, Huizheng; Zhang, Lei; Li, Liquan
• Is Part Of: International journal of hydrogen energy. Volume 44:Number 16(2019)
• Page Start: 8384
• Page End: 8391
• Publication Date: 2019-03-29
• Subjects: Mg3AlNi2 -- Mg3MnNi2 -- Element substitution -- Hydrogen storage -- Electrochemical properties; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2019.02.067
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Al was partially substituted by Mn in Mg3 AlNi2 to improve the discharge capacity and electrochemical kinetic properties of Mg3 AlNi2 alloy electrode. By means of pretreatment of ultrasonic dispersion, followed by mechanical milling and combustion synthesis, a series of quaternary alloys, namely Mg3 Al1- x Mn x Ni2 ( x = 0, 0.2, 0.4, 0.6, 0.8) were synthesized. X-ray diffraction analysis shows that partial substitution of Mn for Al can cause lattice expansion of Mg3 AlNi2 and the samples all appear similar multiphase structures. The introduction of Mn enhances obviously the maximum discharge capacity of Mg3 AlNi2 alloy electrode. The high rate dischargeability of the alloys can also be remarkably enhanced by substitution of Mn for Al. The exchange current density ( I 0 ) and charge transfer resistance ( R ct ) of the alloy electrode increase and decrease continuously with increasing the Mn substitution content, respectively, indicating the improvement of electrochemical kinetics properties. Combining with the potentiostatic discharge test, it is concluded that in the MgAlMnNi quaternary alloys, the kinetic properties are mainly controlled by charge transfer reaction on the electrode surface. Highlights: Al was substituted by Mn in Mg3 AlNi2 to form a quaternary alloy Mg3 Al(Mn)Ni2 . Substitution of Al by Mn increased the discharge capacity of Mg3 AlNi2 remarkably. Kinetic property of Mg3 AlNi2 was improved obviously after Mn substitution for Al. Surface charge transfer reaction played a leading role in the electrode kinetics.