Crystallographic and Electrochemical Characteristics of La_0.7Mg_0.3Ni_5.0−x(Al_0.5Mo_0.5)_x Hydrogen‐Storage Alloys

Abstract

The structure, hydrogen-storage property and electrochemical characteristics of La(0.7)Mg(0.3)Ni(5.0-x)(Al(0.5)Mo(0.5))x (x = 0-0.8) hydrogen-storage alloys have been studied systematically. X-ray diffraction Rietveld analysis shows that all the alloys consist of an La (La,Mg)2Ni9 phase and an LaNi5 phase. The pressure-composition isotherms indicate that the hydrogen-storage capacity first increases and then decreases with increasing x, and the equilibrium pressure decreases with increasing x. Electrochemical measurements show that the maximum discharge capacity and the exchange-current density of the alloy electrodes increase as x increases from 0 to 0.6 and then decrease when x increases further from 0.6 to 0.8. Moreover, the low-temperature dischargeability of the alloy electrodes increases monotonically with increasing x in the alloys.

Study on phase structure and electrochemical properties of Ml1−xMgxNi2.80Co0.50Mn0.10Al0.10 (x=0.08, 0.12, 0.20, 0.24, 0.28) hydrogen storage alloys

“…The capacity at 233 K increases from 36 mAh g −1 (x = 0.08) to 256 mAh g −1 (x = 0.20), and then decreases to 127 mAh g −1 (x = 0.28). It is reported that the low temperature dischargeability is mainly affected by hydrogen diffusion rate in the bulk [18]. The analysis above shows that D is much larger when x is 0.20, so discharge capacity of alloy for x = 0.20 is larger than that of the other alloy electrodes.…”

Effect of temperature on behavior of perovskite-type oxide LaGaO3 used as a novel anode material for Ni-MH secondary batteries

“…In this work, the hydrogen diffusion process and the electrochemical kinetics of the tested oxide were investigated respectively by chronoamperometry and Tafel extrapolation techniques under different temperatures. The hydrogen diffusion coefficient ( D H ) was used to evaluate the mass transport properties of an alloy electrode . The hydrogen diffusion rate can be estimated by the slope of the linear portion of log( i ) versus time t curve (Figure ) by using the following expression: …”

Electrochemical hydrogen storage properties of Ti1.4V0.6Ni quasicrystal and TiH composite materials

“…As an important kinetics property of the hydride electrode in battery, it is very significant to minimize the decrease of discharge capacity even at the high discharge current density [16]. Fig.…”