Effect of alloy composition on enthalpy and entropy changes of hydride formation for stoichiometric and nonstoichiometric hydrogen storage alloys

Investigation of the Structural and Electrochemical Properties of Superstoichiometric Ti-Zr-V-Mn-Cr-Ni Hydrogen Storage Alloys

“…Notten et al 13 found that the high rate dischargeability of over-stoichiometric La 0.8 Nd 0.2 Ni 3.0 Co 2.4 Si 0.1 (AB 5.5 ͒ alloy electrode was much higher than that of the stoichiometric La 0.8 Nd 0.2 Ni 2.5 Co 2.4 Si 0.1 (AB 5 ͒ alloy electrode. A similar result was found by Fukumoto et al 15 and Ye et al, 18 who found that the high rate capability of the Mm(Ni 3.6 Mn 0.4 Al 0.3 Co 0.7 ) x (0.88 р x р 1.12) alloy electrodes and the MmNi x Co 0.75 Mn 0.4 Al 0.3 (3.05 р x р 4.05) alloy electrodes both increased with increasing x. Also, the cycle life was found to be improved by over-stoichiometry.…”

“…It is considered that the nonstoichiometry is an effective technique for changing the electrochemical properties of the hydrogen storage alloys by a special doping and multicomponent alloying. [12][13][14][15][16][17][18] Lee et al 12 formulated a kind of hypostoichiometric Zr-based hydrogen storage alloys, which appeared very promising. Notten et al 13 found that the high rate dischargeability of over-stoichiometric La 0.8 Nd 0.2 Ni 3.0 Co 2.4 Si 0.1 (AB 5.5 ͒ alloy electrode was much higher than that of the stoichiometric La 0.8 Nd 0.2 Ni 2.5 Co 2.4 Si 0.1 (AB 5 ͒ alloy electrode.…”

Effects of Temperature on the Performance of the MmNi[sub 3.6]Co[sub 0.7]Mn[sub 0.4]Al[sub 0.3] Metal Hydride Electrode in Alkaline Solution

“…Recently, many kinds of hydrogen storage alloys have been developed to be widely used as the negative electrodes for the Ni/MH battery [1][2][3] and new electrocatalysts for hydrogen evolution in alkaline water electrolysis. 4,5 It is well known that the performances of the hydrogen storage alloy electrodes and metal hydride ͑MH͒ electrodes are largely dependent on the alloy composition, [6][7][8] stoichiometric ratio x of the Mm͑B 5 ͒ x alloys, [9][10][11][12][13][14] surface properties of the alloys, [15][16][17][18][19][20] and environment temperature. [21][22][23] Until now, various electrochemical parameters in MH electrodes have been widely investigated [21][22][23][24][25] but only a few researchers [26][27][28][29] have reported the MH performances as a function of temperature.…”

The relationship between discharge capacity of LaNi5 type hydrogen storage alloys and formation enthalpy

“…Kandavel and Ramaprabhu [15] have also established a semi-empirical model for the formation enthalpy of Zr-based AB 2 alloys. Fukumoto et al [16] have studied the effects of alloy composition on enthalpy and entropy changes of hydride formation for stoichiometric and nonstoichiometric hydrogen storage alloys. Fang et al [17] have also constructed mathematical models to calculate hydrogen storage properties (formation enthalpy and hysteresis) of AB 2 -type alloys.…”