Microstructures and electrochemical properties of Mg₄₉Ti₆Ni_(45-x)M_x(M = Pd and Pt) alloy electrodes

Abstract

SUMMARY Magnesium – nickel alloys have been considered an alternative for AB5 and AB2‐type alloys in nickel–metal hydride batteries due to their larger maximum discharge capacities, but their low stability in alkaline solution has hindered their use in commercial cells. Aiming to improve the electrode performance of the Mg55Ni45 alloy, we investigated the simultaneous addition of Ti and a noble metal (Pd and Pt) as alloying elements. The investigated system has general composition Mg49Ti6Ni(45‐x)Mx, where M is Pd or Pt, and x assumed values of 0, 2.0 and 4.0 at.%. The electrochemical measurements showed that the Mg49Ti6Ni41Pd4 alloy has the best electrode performance among the studied alloys, reaching 431 mA h g−1 of maximum discharge capacity at the first cycle of charge/discharge. After 10 and 20 cycles, this alloy presented relative discharge capacities of 84 and 77% of the initial one, respectively. The electrode performance of the investigated alloys is discussed in light of results of structural characterization by transmission electron microscopy and X‐ray diffraction. Copyright © 2013 John Wiley & Sons, Ltd.

High‐pressure hydrogen storage properties of Ti x Cr 1 − y Fe y Mn 1.0 alloys

“…The hydrogen storage alloy is critical for the hydrogen storage system. Many hydrogen storage alloys had been investigated, including AB 5 , A 2 B 7 , AB 3 , AB, AB 2 , and light metal Mg system alloy . Typically, the AB 5 ‐type alloys are composed of expensive rare earth metal and Ni .…”

Studies on MgNi-Based Metal Hydride Electrode with Aqueous Electrolytes Composed of Various Hydroxides

“…Research into these two alloy families were reviewed in 2013 [2]. More recently, additives such as B [3], Ti [4,5], Pt [4], Pd [4], Nd [6], Cr [7], AB 5 [8], La [9], Co [10], nano-sized Ni [11], Li [12], and Cu [5,13] were added to the bulk or surface of Mg 2 Ni-based MH alloys to improve the capacity, cycle stability, and high-rate dischargeability (HRD). For MgNi-based MH alloys, TiO 2 addition [14], Ni coating [15], Mn substitution [16], and Nb substitution [17] were experimented for electrochemical property enhancements.…”

Novel hydrogen storage systems and materials

“…This special issue was partially developed from the oral presentations at the symposium on Hydrogen Storage Systems and Materials in the 239th ACS National Meeting held at San Francisco, March 21-25, 2010. However, most of papers in the special issue were from invited contributors in the related research areas.This special issue contains 12 papers, which cover various topics on hydrogen storage, including carbohydrate, metal hydrides, metal-organic frameworks (MOFs), organic polymers, metal-doped graphite, charge-enhanced hydrogen adsorption, and hydrogen storage vessels.Three papers are subjected to hydrides of metal alloys [8][9][10]. Li et al [8] evaluated the hydrogen storage properties of Ti 1Àx Sc x MnCr alloys.…”

“…Three papers are subjected to hydrides of metal alloys [8][9][10]. Li et al [8] evaluated the hydrogen storage properties of Ti 1Àx Sc x MnCr alloys.…”

“…The charging time of a tubular-shaped reactor with liquid cooling channels was 84% less and its storage rate was 39% higher than those of a tubular-shaped simple reactor. Nikkuni et al [10] introduced Ti and a noble metal (Pd or Pt) into the Mg 55 Ni 45 alloy to improve its electrode performance for nickel-based hydride batteries. The Mg 49 Ti 6 Ni 41 Pd 4 alloy exhibited the best electrode performance with 431 mA h g À1 of maximum discharge capacity at the first cycle of charge/discharge.…”