Nickel-metal hydride battery using microencapsulated alloys

Sakai, Tetsuo; Yuasa, Akihiro; Ishikawa, Hiroshi; Miyamura, Hiroshi; Kuriyama, Nobuhiro

doi:10.1016/s0022-5088(06)80027-5

Cited by 75 publications

(24 citation statements)

References 14 publications

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“…It was reported that an approach to reduce such degradation is by surface chemical coating [7][8][9][10][11][12][13][14][15][16]. The coating not only improves the cyclic stability of HSAs, but also remarkably increases the electrocatalytic activity and the rate of the charging/discharging ability.…”

Section: A) B)mentioning

confidence: 99%

Studies of Modified Hydrogen Storage Intermetallic Compounds Used as Fuel Cell Anodes

Chen¹,

Santos²,

Sequeira³

et al. 2011

Crystals

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Abstract:The possibility of substituting Pt/C with the hydrogen storage alloy MlNi 3.6 Co 0.85 Al 0.3 Mn 0.3 as the anode active material of a proton exchange membrane fuel cell system has been analyzed. The electrochemical properties indicate that a much more electrochemically active anode is obtained by impregnating the active material loaded anode in a Nafion proton conducting polymer. Such performance improvement might result from the increase of three-phase boundary sites or length in the gas diffusion electrode where the electrochemical reaction occurs. The experimental data revealed that the membrane electrode assembly (MEA) shows better results when the anode active material, MlNi 3.6 Co 0.85 Al 0.3 Mn 0.3 , is treated with a hot alkaline KBH 4 solution, and then chemically coated with 3 wt.% Pd. The MEA with the aforesaid modification presents an enhanced surface capability for hydrogen adsorption, and has been studied by molecular beam-thermal desorption spectrometry.

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Section: A) B)mentioning

confidence: 99%

Studies of Modified Hydrogen Storage Intermetallic Compounds Used as Fuel Cell Anodes

Chen¹,

Santos²,

Sequeira³

et al. 2011

Crystals

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“…In order to improve the activation property of the Zr-based alloy electrode, various treatments such as KBH 4 treatment, pulse-charging and hot-charging treatment have been suggested [4][5][6]. However, these proposed treatments were not satisfactory from the viewpoint of avoiding the overcharge of the Ni(OH) 2 electrode or applying the formation process of the Ni/MH battery.…”

Section: A New Activation Process For a Zr-based Alloy Electrodementioning

confidence: 99%

“…It has been reported that rate-capability is mainly controlled by surface reaction kinetics, which depends on the metallic Ni or some Ni-rich phase on the alloy surface [4,5]. On the other hand, it was recently reported that some hyper-stoichiometric Zr-based Laves phase alloys showed excellent hydriding and electrochemical characteristics compared with those of the stoichiometric alloys [6].…”

Section: Introductionmentioning

confidence: 99%

The performances of proto-type Ni/MH secondary batteries using Zr-based hydrogen storage alloys and filamentary type Ni

lee

kim

et al. 2001

Met. Mater. Int.

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For the purpose of developing a Zr-based Laves phase alloy with higher capacity and better performance for electrochemical application, extensive work has been carried out. After careful alloy design of ZrMn 2 -based hydrogen storage alloys through varying their stoichiometry by means of substituting or adding alloying elements, the Zr 0.9 Ti 0.1 (Mn 0.7 V 0.5 Ni 1.4 ) 0.92 with high capacity (392 mAh/g at the 0.25C) and improved performance (comparable to that of commercialized AB 5 type alloy) was developed. Another endeavor was made to improve the poor activation property and the low rate capability of the developed Zr-based Laves phase alloy for commercialization. The combination method of hot-immersion and slow-charging was introduced. It was found that electrode activation was greatly improved after hot immersion at 80 o C for 12 h followed by charging at 0.05C. The effects of this method are discussed in comparison with other activation methods. The combination method was successfully applied to the formation process of 80 Ah Ni/MH cells. A series of systematic investigations has been rendered to analyze the inner cell pressure characteristics of a sealed type Ni-MH battery. It was found that the increase of inner cell pressure in the sealed type Ni/MH battery of the above-mentioned Zr-Ti-Mn-V-Ni alloy was mainly due to the accumulation of oxygen gas during charge/discharge cycling. The fact identified that the surface catalytic activity was affected more dominantly by the oxygen recombination reaction than the reaction surface area was also identified. In order to improve the surface catalytic activity of a Zr¯Ti¯Mn¯V¯Ni alloy, which is closely related to the inner pressure behavior in a sealed cell, the electrode was fabricated by mixing the alloy with Cu powder and a filamentary type of Ni and replacing 75% of the carbon black with them; thus, the inner cell pressure rarely increases with cycles due to the active gas recombination reaction. Measurements of the surface area of the electrode and the surface catalytic activity showed that the surface catalytic activity for the oxygen recombination reaction was greatly improved by the addition of Cu powder and the filamentary type of Ni. Finally, we have collaborated with Hyundai Motors Company on fabrication of the 80Ah cells for Electric Vehicles and evaluated the cell performance.

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“…Among studies under improvement of corrosion stability of powdered hydride electrodes, there appear papers dealing with protection of active particles by metallic coatings [9,10,[17][18][19][20][21][22]. As the efficient coatings, the surface layers of such metals as Cu, Ni, Co, and Pd have been successfully applied.…”

Section: Introductionmentioning

confidence: 99%

Inhibition of LaNi5 electrode decay in alkaline medium by electroless encapsulation of active powder particles

Dymek

Bala

2016

J Solid State Electrochem

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Surface of powdered LaNi 5 intermetallic compound has been modified by active particle coverage with electroless nickel (Ni-P). The electrode degradation process in 6 M KOH solution has been tested across 70 charge/ discharge cycles at −0.5 C/+0.5 C rates. It has been established that after approx. 25-35 initial cycles, the electrode degradation process fulfills first order chemical reaction kinetics law: logarithm of discharge capacity linearly decreases with cycle number. The rate constant for the Ni-P protected material is over 20 % lower than that of as received one. The surface modification also improves the alloy hydrogenation kinetics: exchange current densities of H 2 O/H 2 system are generally greater for modified material and, contrary to uncovered material, do not practically decrease with long-lasting cycling.

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Nickel-metal hydride battery using microencapsulated alloys

Cited by 75 publications

References 14 publications

Studies of Modified Hydrogen Storage Intermetallic Compounds Used as Fuel Cell Anodes

Studies of Modified Hydrogen Storage Intermetallic Compounds Used as Fuel Cell Anodes

The performances of proto-type Ni/MH secondary batteries using Zr-based hydrogen storage alloys and filamentary type Ni

Inhibition of LaNi5 electrode decay in alkaline medium by electroless encapsulation of active powder particles

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