Application of thermal electrochemical equation to metal-hydride half-cell system

Abstract

Application of thermal electrochemical equation to metal-hydride half-cell system was investigated, and the influence of state of charge on the thermal electrochemical performance of hydrogen storage materials was studied. The results show that both the absolute value of the molar enthalpy change and the internal resistance of evolution hydrogen reaction are less than that of absorption hydrogen reaction at the same state of charge. The molar reaction enthalpy change of absorption and evolution of hydride electrode change contrarily with the enhancement of filling degree of hydrogen in hydride electrode. The relation curve of molar reaction enthalpy change to state of charge, both absorption and evolution hydrogen reaction, is close to a constant when the state of charge is 10%–60%, and during state of charge below 10% or state of charge above 60%, the molar reaction enthalpy change varies sharply. Meanwhile, the internal resistance of electrode reaction has an ascending trend with the enhancement on filling degree of hydrogen in hydride electrode in both absorption and evolution hydrogen reaction.

Keywords

hydrogen storage material / thermal electrochemical method / state of charge / application / change of enthalpy / internal resistance

References

[1] GaoE Q, ZhouZ Y. Preparation and property of La-Ni-Co hydrogen storage alloy[J]. Applied Chemistry, 1997, 18(1): 24-35

[2] HongC M, LinQ Z, HanD G, et al.. The kinetics of absorbing hydrogen of LaNi₅ hydrogen storage alloy[J]. Transaction of Physical Chemistry, 1992, 8(5): 586-594

[3] ZhouZ X, HeC H, WangZ P, et al.. The thermodynamics function of rare hydrogen storage alloy determined by electrochemical method[J]. Transaction of Physical Chemistry, 1992, 8(4): 558-562

[4] HaranB S, PopovB N. Theoretical analysis of metal hydride electrodes[J]. J Electrochem Soc, 1998, 145(12): 4082-4089

[5] RalphE, WhiteT. Electrochemical impedance spectra and deterioration mechanism of metal hydride electrodes[J]. J Electrochem Soc, 1992, 133(7): 172-183

[6] BowmanR C, WithamC, FultzB, et al.. Hydriding behavior of gas-atomized AB₅ alloys[J]. J Alloys and Comp, 1997, 253–254: 613-616

[7] ObisukaM, YinD Y. Chemical method composition of hydrogen storage alloy materials [J]. J Alloys and Comp, 1995, 230: 46-52

[8] SoloninY M, SavinV V, SoloninS M, et al.. Gas atomized powders of hydride-forming alloys and their application in rechargeable batteries[J]. J Alloys and Comp, 1997, 253–254: 594-597

[9] LichenbergF, KohlerU, FolerA, et al.. Devepartment of AB₅ type hydrogen storage alloys with low Co content for rechargeable Ni-MH batteries with respect to electric vehicle applications[J]. J Alloys and Comp, 1997, 253–254: 570-573

[10] LiuKai-yu, ZhangPing-min, TangYou-gen, et al.. The effects of two-step heat treatment on properties of hydrogen storage alloys electrode[J]. Journal of Central South University of Technology: Science and Technology, 2003, 34(1): 44-48(in Chinese)

[11] XuGuang-xianRare earth, 19952nd edBeijing, Metallurgyical Industry Press(in Chinese)

[12] FangZ, ZhangH Z, ZhangP M, et al.. Basic equations for thermo-electro-chemistry and the entropy change of the standard hydrogen electrode reaction[J]. Acta Metallurgical Sinica, 1996, 9(3): 189-191

[13] FangZ, GuoL. Determination of the entropy change for electrode reaction and dilute enthalpy of some ions by thermo-electro-chemical technology[J]. Journal of Central South University of Technology, 1998, 5(1): 38-40

[14] ShibataS, SuminaM P, YamadaA. A system of thermo-electro-chemical measurement by heat sensitive resistance[J]. J Electroanal Chem, 1985, 193: 123-128

[15] BoudevilleP. Peltier heat of electrode reaction is measured by methods of calorimetry and thermal analysis[J]. Thermochimica Acta, 1988, 126: 221-228

[16] LiuKai-yu, ZhangPing-min, TangYou-gen. Preparation of low cobalt high rate discharge hydrogen storage alloy MlNi_3.85Co_0.45Mn_0.4Al_0.3X_0.1(X = Mg,Si,Sn)[J]. Transactions of Nonferrous Metals Society of China, 2003, 13(2): 245-248

[17] LiuKai-yuStudy on preparation of dynmaical type hydrogen storage alloy and assessment of thermal electrochemistry[D], 2003, Changsha, School of Chemistry and Chemical Engineering, Central South University(in Chinese)