AB3.3~3.7型La-Y-Ni稀土储氢合金微观结构和电化学性能研究  

Microstructure and Electrochemical Properties of AB3.3~3.7-Type La-Y-Ni Rare Earth Storage Alloys

作　　者：郭淼 苑慧萍 刘彧儒 蒋利军 Guo Miao;Yuan Huiping;Liu Yuru;Jiang Lijun(GRIMAT Engineering Instiute Co.,Ltd.,Beijing 101407,China)

机构地区：[1]有研工程技术研究院有限公司,北京101407

出　　处：《稀有金属》2023年第2期210-217,共8页Chinese Journal of Rare Metals

基　　金：工信部工业转型升级强基工程项目(0714-EMTC02-5379/4)资助。

摘　　要：采用磁悬浮感应熔炼的方法制备了(LaSmY)(NiMnAl)x(x=3.3,3.4,3.5,3.6,3.7)系列稀土储氢合金,并在氩气气氛、1273 K下热处理24 h。通过X射线衍射(XRD)和电化学测试分析了合金的相结构以及在常温和低温下的电化学性能。结果表明,合金为多相结构,含有Ce_(2)Ni_(7)相、PuNi_(3)相、Gd_(2)Co_(7)相、LaNi_(5)相以及Ce_(5)Co_(19)相。主相Ce_(2)Ni_(7)相的含量随化学计量比x值的增加先增加后降低,当x=3.5时最高,为74.67%。Gd_(2)Co_(7)相和PuNi_(3)相含量随x值的增加逐渐降低,Ce_(5)Co_(19)相逐渐增加。电化学测试结果表明,在常温下,随化学计量比x值的增加,合金的最大放电容量从317.7 mAh·g^(-1)(x=3.3)增加到353.4 mAh·g^(-1)(x=3.5),然后降至343.8 mAh·g (x=3.7)。循环容量保持率随x值的先增加后降低,当x值为3.4时最佳,循环300周后容量保持率(S300)为84.75%。高倍率性能(HRD1200)从62.00%(x=3.3)增加到77.56%(x=3.7)。在低温下,合金电极的放电性能随温度的降低而降低,容量保持率随x值的变化规律与常温下高倍率性能的变化保持一致。在温度为248 K的情况下,x=3.7的合金电极具有最高的容量保持率,为56.71%。In response to the goals of carbon peak and carbon neutralization,a large number of pure electric vehicles (EVs),hybrid electric vehicles (HEVs),plug-in hybrid electric vehicles (PHEVs) and fuel cell vehicles (FCVs) were being promoted and used.Nickel metal hybrid (Ni-MH) batteries played an important role in the battery-powered electric vehicles market,especially in the hybrid electric vehicles,due to their excellent high-rate dischargeability,high energy density and good safety.As one of the power sources of hybrid electric vehicles,the performance of Ni-MH batteries was crucial.LaNi_(5)and La-Mg-Ni-based rare earth hydrogen storage alloys were the main anode materials for Ni-MH batteries.La-Mg-Ni-based hydrogen storage alloy with a superlattice structure had higher discharge capacity and better activation performance than LaNi_(5)alloy.However,the lower melting point of Mg element made it easy to volatilize during the preparation of the hydrogen storage alloy,and the alloy composition was difficult to control.A recent study found that the superlattice La-Y-Ni-based rare earth hydrogen storage alloy,like La-Mg-Ni-based alloy,had higher discharge capacity and better activation performance,but the cycle performance was slightly different.After Sm element substitution,the cycle life of LaY-Ni-based hydrogen storage alloy was improved,but the discharge capacity and high-rate performance decreased.In order to improve the overall performance of La-Y-Ni hydrogen storage alloy after Sm substitution,the effect of the stoichiometric ratio B/A on the phase structure and the electrochemical properties of La-Sm-Y-Ni-Mn-Al alloy at room temperature and low temperature was systematically investigated.(LaSmY)(NiMnAl)x(x=3.3,3.4,3.5,3.6,3.7) alloys were prepared by magnetic suspension induction melting method and annealed in argon at 1273 K for 24 h.The purity of La,Sm,Y,Ni,Mn and Al materials was 99.9%.To compensate for the oxidation loss,an excess of 2%La,2%Sm,1%Y,1%Mn and 1%Al was added.The phase structure and the electroche

关 键 词：稀土储氢合金 镍氢电池 化学计量比 电化学性能 

分 类 号：TG139.7[一般工业技术—材料科学与工程]