Effect of particle size on the electrochemical properties of MmNi3.8Co0.75Mn0.4Al0.2 hydrogen storage alloy |
| |
Authors: | Xiangyu Zhao Liqun Ma Yi DingXiaodong Shen |
| |
Affiliation: | College of Materials Science and Engineering, Nanjing University of Technology, No.5 Xinmofan Road, Nanjing 210009, P.R. China |
| |
Abstract: | Charge and discharge testing, linear polarization, electrochemical impedance spectroscopy (EIS) and potential step chronoamperometry (PSCA) were used to investigate the electrochemical properties of the Ce-rich mischmetal MmNi3.8Co0.75Mn0.4Al0.2 hydrogen storage alloy with different particle sizes. At a discharge current density of 900 mA/g, the alloy with small original particle size maintained a high rate dischargeability (HRD) above 86% while the alloy with large particle size could not discharge in the same potential region. The alloy with small original particle size also showed lower contact resistances and polarization resistance after full activation. Both the exchange current density and the hydrogen diffusion coefficient increased when the hydrogen concentration decreased. The charge-transfer reaction on the surface of alloy particles with different sizes should be mainly responsible for the differences in electrochemical properties, especially the HRD. |
| |
Keywords: | Hydrogen storage alloy Particle size High rate dischargeability Charge-transfer Hydrogen diffusion |
本文献已被 ScienceDirect 等数据库收录! |