( 1. 西安交通大學(xué) 金屬材料強(qiáng)度國(guó)家重點(diǎn)實(shí)驗(yàn)室， 西安 710049；
2. 陜西省鍋爐壓力容器檢測(cè)所， 西安 710049)
摘 要: 通過(guò)感應(yīng)容煉制備了La0.8-xRExMg0.2Ni3.2Co0.6(RE=Sm, Dy, 0 ≤x ≤ 0.3) 合金。 采用X射線衍射分析了該合金的晶體結(jié)構(gòu)， 并研究了其電化學(xué)性能。 結(jié)果表明: 該合金是由LaNi5主相和LaNi3第二相構(gòu)成; 隨著Sm(Dy)取代La量的增加， 合金主相單胞體積線性收縮， 合金儲(chǔ)氫量和放電容量減小， 當(dāng)Sm(Dy)取代量分別為0.1、 0.2、 0.3時(shí)， 合金容量由380 mA·h/g分別減小到370(362)、 355(334)、 329(295) mA·h/g， 但高倍率放電能力和循環(huán)穩(wěn)定性得到改善， 100次循環(huán)后的容量損失率由20%分別降低到18%(17%)、 16%(14%)、 13%(11%)。
關(guān)鍵字: 鎳氫電池； 儲(chǔ)氫合金； 稀土； 放電容量
YU Guang1, ZHU Jie-wu1, LIU Xiao-dong2
（ 1. State Key Laboratory for Mechanical Behavior of Materials,
Xi'an Jiaotong University, Xi'an 710049, China;
2. Shaanxi Measurement Institute for Boiler Pressure Vessel, Xi'an 710049, China）
Abstract: La0.8-xRExMg0.2Ni3.2Co0.6(RE=Sm, Dy, 0≤x≤0.3) alloys were prepared by inductive melting. The crystal structure of the alloys was determined by X-ray powder diffractrometry and the electrochemical properties were investigated. The results show that the alloys are composed of LaNi5 as matrix and LaNi3 as secondary phase. With the increasing Sm (Dy) substitution for La, the unit cell volume of matrix of the alloys shrinks linearly and both the hydrogen storage capacity and discharge capacity decrease. When the Sm (Dy) substitution (x value) is 0.1, 0.2 and 0.3, the discharge capacity decreases from 380 mA·h/g to 370(362), 355(334) and 329(295) mA·h/g, respectively. However, the rate performance and cycle stability is improved. After 100 cycles, the capacity loss decreases from 20% to 18%(17%), 16%(14%) and 13%(11%).
Key words: nickel-metal hydride battery; hydrogen storage alloy; rare earth; discharge capacity
