Effect Of Partial Substitution Of Sm For La、Y On The Structure And Electrochemical Properrties Of LaY₂Ni₁₀Mn_0.5 Hydrogen Storage Electrode Alloy

La_1-xY_2-2xSm_3xNi₁₀Mn_0.5（x=0,0.05,0.10,0.15） hydrogen storage alloys were prepared using a vacuum induction-quenching furnace. This paper investigated the phase structure and electrochemical performance of as-quenched and annealed hydrogen storage alloy electrode alloy at 298K and low temperature （253K） systematically.XRD and SEM analysis suggests that La_1-xY_2-2xSm_3xNi₁₀Mn_0.5（x=0,0.05,0.10, 0.15） alloys have multiphase structure including the main Ce2Ni7 phase,Gd2Co7 phase and a small amount of YNis phase.The Ce2Ni7 phase increases, The Gd2Co7 phase and YNi5 phase descrease with the increase in Sm element content.At the same time,the unit cell volume of Ce2Ni7 phase is almost unchanged and the unit cell volume of Gd2Co7 phase shows a decreasing tendency.At 298K,the maximun discharge capacity of the alloy electrodes decreases, and the cycle stability descreases slightly with increasing x.As Sm content increases,the high-rate dischargeability （HRD） decreases.With the increase of heat treatment temperature, the La0.9Y1.8Sm0.3Ni10Mn0.5 hydrogen storage alloy is still composed of multi-phase whose the unit cell volume does not chang obviously.The abundant of Ce2Ni7 phase first descreases then increases,Gd2Co7 phase has an opposite changing tendency and YNi5 phase gradually descreases until it disappears. The maximum discharge capacity and cycle stability of the annealed alloy electrodes show an increasing tendency. The high-rate dischargeability （HRD） of the alloy electrodes first increases then descreases with the increase of annealed temperature.The exchange current density I0,the limiting current density IL, electrochemial impedance spectra and the hydrogen diffusion coefficient D of the alloy electrodes indicate the factors that affect the electrochemical kinetics.The maximum capacity and cycle stability increase, the high-rate dischargeability （HRD） decrease with the increase of Sm content in253K for La_1-xY_2-2xSm_3xNi₁₀Mn_0.5（x=0,0.05,0.10,0.15）alloys annealed at 1148K.