Ni/MH Rechargeable Battery with Zr-Based Hydrogen Storage Alloy Electrode Modified by High Surface Area of Ni Powder

Abstract

Efforts to improve the surface catalytic activity of electrodes has been made to decrease the internal pressure of a sealed Ni-MH battery in which the low-cost false(normalZr­normalSn)0.8Ti0.2false(Mn0.7false(V­normalFe)0.5Cr0.05Ni1.05)0.9 alloys are used as the anode. To improve the surface catalytic activity of the Zr-based alloy which is closely related to the inner cell pressure behavior in a sealed cell, the electrode was fabricated by mixing the alloy with Cu powder and filamentary Ni powder. By replacing 25% of carbon black by filamentary Ni powder, the inner cell pressure has been suppressed significantly. The main reason for the reduction of inner cell pressure is the increase of overall surface catalytic activity of the Zr-based alloy electrode by addition of the filamentary Ni powder with high surface area. The filamentary Ni powder-mixed electrode has a surface area comparable to that of carbon black. It is assured that the Ni powder plays a role in enhancing a specific surface catalytic activity for the oxygen recombination reaction on the MH surface. © 2002 The Electrochemical Society. All rights reserved.

Electrochemical Hydrogen Storage Behaviors of Ultrafine Amorphous Co−B Alloy Particles

“…Hydrogen storage alloys (HMs) have been actively investigated as a high capacity negative material of nickel−metal hydride batteries for use in various electronic devices and hybrid low-emission vehicles. − In the past few decades, many metal hydrides, such as AB 5 -type rare-earth metal alloys, − AB 2 -type Laves phase alloys, , A 2 B-type Mg-based alloys, , and AB-type intermetallic compounds, , have been explored, and a large amount of work, such as the optimization of alloy composition − and surface modifications, − has been done to improve the electrochemical capacity and high rate capability of these materials. Though some of the Mg-based alloys have very high capacities of ≥600 mAh/g, their cycling abilities and poor dynamics are insufficient for practical applications. , At the present state of the art, the commercially used MHs usually have a reversible capacity of ∼300 mAh/g, , and therefore, the search for new hydrogen storage materials with higher energy density has been continuously carried out in recent years.…”

Electrochemical properties of rare-earth based hydrogen storage alloy for replacing Pt as the anode electrocatalyst in AFC

“…[1][2][3][4][5][6]. For the anode active material of AFC, the operating temperature and pressure are close to environment value and 30-40 wt% KOH is employed as its electrolyte, all of which are similar with the operating conditions of the negative material of Ni/MH battery.…”