Electrochemical Properties of Zr0.8Ti0.2Mn0.4V0.6Ni1-xFex Alloy Electrodes

Zr0.8Ti0.2Mn0.4V0.6Ni1-xFex 합금 전극의 전기화학적 특성

  • Song, MyoungYoup (Division of Advanced Materials Engineering, Research Center of Industrial Technology, Engineering Research Institute, Chonbuk National University) ;
  • Kwon, IkHyun (Division of Advanced Materials Engineering, Research Center of Industrial Technology, Engineering Research Institute, Chonbuk National University) ;
  • Lee, DongSub (Division of Advanced Materials Engineering, Research Center of Industrial Technology, Engineering Research Institute, Chonbuk National University)
  • 송명엽 (전북대학교 공학연구원 공업기술연구센터 신소재공학부) ;
  • 권익현 (전북대학교 공학연구원 공업기술연구센터 신소재공학부) ;
  • 이동섭 (전북대학교 공학연구원 공업기술연구센터 신소재공학부)
  • Published : 2002.09.15

Abstract

A series of multicomponent $Zr_{0.8}Ti_{0.2}Mn_{0.4}V_{0.6}Ni_{1-x}Fe_{x}$ (x=0.00, 0.08, 0.15, 0.22, and 0.30) alloys are prepared and their oystal structure and P-C-T curves are examined. The electrochemical properties of these allqys such as activation conditions, discharge capacity, cycling performance are also investigated. $Zr_{0.8}Ti_{0.2}Mn_{0.4}V_{0.6}Ni_{1-x}Fe_{x}$ (x=0.00, 0.08, 0.15, 0.22 and 0.30) have the C14 Laves phase hexagonal structure. The electrode was activated by the hot-charging treatment. The best activation conditions were the current density 120 mA/g and the hot-charging time 12h at $80^{\circ}C$ in the case of the alloy with x=0.00. The discharge capacity increased rapidly until the fourth cycle and then decreased. The discharge capacity increased again from the 13th cycle, arriving at 234 mAh/g at the 50th cycle. The discharge capacily just after activation decreases with the increase in the amount of the substituted Fe but the cycling performance is improved. The discharge capacity after activation of the alloy with x=0.00 is 157 mAh/g at the current density 120 mA/g. $Zr_{0.8}Ti_{0.2}Mn_{0.4}V_{0.6}Ni_{0.85}Fe_{0.15}$ is a good composition with a medium quantity of discharge capacities and a good cycling performance. The ICP analysis of the electrolyte for these electrodes after 50 charge-discharge cycles shows that the concentrations of V and Zr are relatively high. Another series of multicomponent $Zr_{0.8}Ti_{0.2}Mn_{0.4}V_{0.6}Ni_{0.85}M_{0.15}$ (M = Fe, Co, Cu, Mo and Al) alloys are prepared. They also have the C14 Laves phase hexagonal structure. The alloys with M = Co and Fe have relatively larger hydrogen storage capacities. The discharge capacities just after activation are relatively large in the case of the alloys with M = Al and Cu. They are 212 and 170 mAh/g, respectivety, at the current density 120mA/g. The $Zr_{0.8}Ti_{0.2}Mn_{0.4}V_{0.6}Ni_{0.85}Co_{0.15}$ alloy is the best one with a relatively large discharge capacity and a good cycling performance.

Keywords

$AB_2$-type metal hydride electrode;Hot-charging treatment;Discharge capacity;Cycling performance;ICP spectroscopy

Acknowledgement

Supported by : 전북대학교

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