稀土La-Yb掺杂对海水电池阳极镁合金微观组织及电化学性能影响  

Effects of Rare Earth La-Yb Doping on Microstructure and Electrochemical Performance of Magnesium Alloys Used as Anode for Seawater Batteries

作　　者：杨清竹 连利仙[1] 刘颖[1] Yang Qingzhu;Lian Lixian;Liu Ying(College of Materials Science and Engineering,Sichuan University,Chengdu 610065,China)

机构地区：[1]四川大学材料科学与工程学院,四川成都610065

出　　处：《稀有金属材料与工程》2025年第3期755-764,共10页Rare Metal Materials and Engineering

基　　金：四川省杰出青年科学基金(2023NSFSC1942);四川大学国家双一流大学建设专项资金(2020SCUNG201)。

摘　　要：利用机械合金化与放电等离子烧结工艺相结合制备了AZ91-La-Yb海水电池用阳极镁合金,并系统研究了稀土La-Yb掺杂对阳极材料微观组织及电化学行为的影响。结果表明:通过机械合金化-放电等离子烧结工艺制备的AZ91-La-Yb合金由等轴晶构成,一方面,掺杂La-Yb后,形成了在晶界处均匀分布的微米级(0.5~2μm)富RE相,该相主要由稀土单质(RE=La,Yb)及Mg(RE)固溶体共同组成;另一方面,通过放电等离子烧结引起的塑性变形作用以及稀土La-Yb的掺杂效应,显著改善了β-Mg_(17)Al_(12)相的形貌,使其由粗大的网状转变为纤细的长条状。均匀分布的微米级富RE相及更加细小的β相联合作用,共同促进了镁合金的均匀溶解放电,同时有效缓解了镁合金的局部腐蚀。与AZ91阳极用镁合金相比,掺杂了稀土La-Yb的AZ91-La-Yb表现出更加平稳的放电电压及良好的放电性能,在20 mA/cm^(2)的电流密度下,其比容量可达1068 mAh/g,阳极利用率为50.4%。AZ91-La-Yb magnesium alloy as anode of seawater batteries was prepared by combining mechanical alloying with spark plasma sintering processes.The effects of rare earth La-Yb doping on the microstructure and electrochemical behavior of AZ91 anode were studied.The results show that the AZ91-La-Yb alloy prepared by mechanical alloying-spark plasma sintering processes consists of equiaxed grains.On the one hand,La-Yb doping results in the formation of micron-scale(0.5–2μm)RE-rich phase that are uniformly distributed at grain boundaries.This phase is mainly composed of rare earth metals(RE=La,Yb)and Mg(RE)solid solution.On the other hand,the plastic deformation caused by discharge plasma sintering and the doping effect of rare earth elements La-Yb significantly improve the morphology ofβ-Mg_(17)Al_(12)phase,transforming from a coarse network structure to a slender elongated shape.The combination of uniform distribution of nearly micron-scale RErich phase and the smallerβphase promotes the uniform dissolution of magnesium alloys and effectively alleviates localized corrosion of magnesium alloys.Compared to the AZ91 anode magnesium alloy,the AZ91-La-Yb alloy doped with rare earth La-Yb exhibits more stable discharge voltage and excellent discharge performance.At a current density of 20 mA/cm^(2),its specific capacity can reach 1068 mAh/g,and the anode utilization efficiency is 50.4%.

关 键 词：机械合金化 放电等离子烧结 海水电池 稀土掺杂 AZ91-La-Yb阳极 

分 类 号：TG146.22[一般工业技术—材料科学与工程]