| In secondary battery MH/Ni with hydrogen storage alloy of research and development, Because of the high vanadium alloy hydrogen storage and release hydrogen temperature moderate and anti-pulverization ability. Thus used as high-energy MH/Ni battery anode materials after the selected by the attention of people, But because of vanadium and vanadium crystallology itself in alkaline solution lack of electricity catalytic activity generally have no reversible electrochemical on hydrogen ability, Thus vanadium alloy have failed to interstitial single-phase electrochemical system has been applied. In order to improve the vanadium alloy electrical catalytic activity, People through the alloy component design type BCC crystallology form of heterogeneous phase structure, One is a large number of the BCC hydrogen storage function of hydrogen, The second phase TiNi C15 or Laves type is handed down in the three-dimensional network structure of grain separation to increase the electrode reaction dynamics performance. But vanadium crystallology hydrogen storage material in electrochemical store hydrogen, Because in electrolyte of vanadium oxide dissolution has been difficult to overcome and the life cycle, so poor, Which hindered the Ni/MH battery in the practical application. In order to further improve vanadium hydrogen-storage alloy electrode electrochemical reaction kinetics and life cycle, Researchers in vanadium alloy alloying, composite and surface modification of some research. Based on the Tio.28 Cro.217 V0.42 Fe0.083 vanadium alloy for the matrix, by adding 30%(wt) of rare earth alloy A2B7 Lao.63 Gd0.2Mg0.17 Ni3.1 Co0.3 Al0.1 for catalytic activity materials, adopting mechanical ball mill modification of hydrogen storage alloys prepared composite electrode materials, the system of hydrogen storage characteristics and electrochemical properties and draw the following conclusions:Vanadium hydrogen-storage alloy Ti0.28 Cr0.217 V0.42 Fe0.083 gaseous hydrogen storage capacity can be reached 3.1%(wt) should have high capacitytheory of electrochemical (946mAh/g),but the catalytic activity was very poor, Io was measured values only 10.5 mA/g at room temperature, conditions hardly electrochemical on hydrogen capacity. While lanthanated-Ni-based-magnesium alloy Lao.63 Gdo.2 Mgo.17 Ni3.1 Co0.3 Al0.1 electricity better catalytic activity, the exchange of current Io can achieve 260.2 mA/g, the maximum discharge capacity under normal temperature, the 390mAh/g reached 100 cycle after discharge capacity, the rate of keeping 94% that use lanthanated-Ni-based-magnesium alloy, Lao.63 Gdo.2 Mgo.17 M3.1 Co0.3 Al0.1 as vanadium alloy of surface modification of the material is feasible.The XRD, SEM and TEM analyses show that the particle size of the milled composite sample decrease gradually and the powder appears aggregation, the uniform disperse and encapsulation of the A2B7 alloy particles on the surface of the v based alloy particles were formed with the increasing ball-milling time. It was found that nano-cyrstaline structure composite and partial amorphrization were formed when milling time was large than 5 hours, while the crystal parameters a and cell volume V of bcc phase structure in the composite decreased. Hydrogen storage capacity of v based alloy milled for 10 h decreased, hydrogen storage capacity of the milled composite exhibits increases first and then decreases, whose maximum hydrogen absorption capacity at room temperature approach to 2.5% Electrochemical studies show that the electrochemical properties of the milled composite were enhanced, the maxmum discharge capacity were 425.8mAh/g, Alloy surface catalytic activity greatly improved Io value by 10.5 mA/g increases to 181.8 mA/g. the cyclic stability of the composite electrode is noticeably improved in comparison with singleA2B7 type alloy electrode.After 100 charge-discharge cycles the discharge capacity retention rate C100/Cmax of milled composite electrode is 97%, which exhibits a good cycle life than that of the A2B7 alloy electrode.
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