Influence of Zr Addition on Structure and Performance of Rare Earth Mg-Based Alloys as Anodes in Ni/MH Battery

Abstract

Abstract:In this study, the substitution of Mg with Zr in La 0.7 Mg 0.3 (Ni 0.85 Co 0.15 ) 3.5 was carried out with the purpose of improving the electrochemical performances. The structural and hydrogen storage properties in both gas-solid reaction and the electrochemical system were systematically studied on La 0.7 (Mg 0.3−x Zr x )(Ni 0.85 Co 0.15 ) 3.5 (x = 0.05, 0.1, 0.2, 0.3) alloys. Each tested alloy is composed of LaNi 3 phase, LaNi 5 phase and ZrNi 3 phase with different phase abundances. The electrochemical studies indicated that all Zr-substituted anodes possessed a much higher cycling capacity retention than pristine La 0.7 Mg 0.3 (Ni 0.85 Co 0.15 ) 3.5 . However, the maximum discharge capacity was reduced with the increase of Zr content. The potential-step tests showed that the diffusion of hydrogen atoms inside the anodes was decelerated after the introduction of Zr.

The Co-B Amorphous Alloy: A High Capacity Anode Material for an Alkaline Rechargeable Battery

“…For example, S C has an extremely high maximum discharge capacity of 844.6 mAh/g, which is much higher than that of conventional hydrogen storage alloys [1][2][3][4][5][6]. The maximum discharge capacity of S S and S N are 669.8 and 367.0 mAh/g, respectively.…”

“…In the past few decades, extensive studies on hydrogen storage alloys (HMs) as anode materials of nickel-metal hydride (Ni-MH) batteries have been reported as being used in portable electronics due to their high specific capacity, good durability, and environmental friendliness [1][2][3][4][5][6]. Up to now, many kinds of metal hydrides have been developed; for instance, Mg-based alloys exhibit a maximum discharge capacity above 500 mAh/g, but the poor cycling ability limits widespread practical application [7].…”

Electrochemical Properties of Nb-Substituted Zr-Ti-Ni Hydrogen Storage Alloy Negative Electrodes for Nickel-Metal Hydride Batteries

“…The way to destabilize hydrides is to reduce the lattice constant or the unit cell volume by partially replacing the alloy constituents with another element whose atomic radius is smaller [10,11]. Recently, we have reported on the ternary AB-type Zr 1−x Ti x Ni (0.05 ≤ x ≤ 0.5) alloys, in which the Zr constituent was partially replaced with Ti whose atomic radius is smaller than Zr (r Zr = 1.60 Å and r Ti = 1.47 Å), and have assessed their crystallographic, thermodynamic and electrochemical properties [12,13].…”

Enhancement of the electrochemical properties of rare earth-based alloy by doping with CoZnB alloy

“…At several higher discharge densities, high-rate dischargeability (HRD) was measured. Using an electrochemical workstation (Zahner Elektrik IM6e), linear polarization (LP), electrochemical impedance spectroscopy (EIS), potential-step discharge and anodic polarization (AP) were measured at 298 K. The experimental conditions for these electrochemical tests were referenced to our previous study [24].…”