Effect of crystal transformation on electrochemical characteristics of La–Mg–Ni-based alloys with A2B7-type super-stacking structures
Effect of crystal transformation on electrochemical characteristics of La–Mg–Ni-based alloys with A2B7-type super-stacking structures
复制标题
晶相转变对A2B7型超堆垛结构La-Mg-Ni基合金电化学性能的影响
DOI：
10.1016/j.ijhydene.2013.09.049
复制
发表时间：
2013-11
影响因子：
7.2
通讯作者：
Linda Che
中科院分区：
文献类型：
--
作者：
Yuan Li;Junling Zhang;Yumeng Zhao;Linda Che
采用粉末冶金法制备了具有六方（2 H-）和菱方（3R-）（La，Mg）2Ni 7相的La0.75Mg0.25Ni3.5合金。通过热处理和引入LaNi 5化合物实现了2 H-向3R型同素异形体的部分晶型转变。结果表明，在1073-1223 K范围内退火后，合金保持了（La，Mg）2Ni 7相，当退火温度达到1223 K时，合金发生了明显的由2 H-向3R型的晶型转变。电化学研究表明，不同2 H和3R型同素异形体含量的La0.75Mg0.25Ni3.5合金具有相似的放电容量和降解行为，而3R型同素异形体含量的增加有利于提高合金的HRD。在La0.75Mg0.25Ni3.5合金中引入LaNi 5增加了3R型与2 H型相的比例，并导致P-C等温线中出现额外的平台。LaNi_5的引入提高了HRD，但加速了循环退化。Rietveld分析表明，氢化后2 H型和3R型（La，Mg）2Ni 7相的晶胞膨胀率相近，而LaNi 5相的晶胞膨胀率小于（La，Mg）2Ni 7相。这导致（La，Mg）2Ni 7和LaNi 5相之间的离散胞膨胀，导致严重的粉化和氧化。
La0.75Mg0.25Ni3.5alloys with hexagonal (2H-) and rhombohedral (3R-) (La,Mg)2Ni7phase were created by powder metallurgy. Partial crystal transformation of 2H- into 3R-type allotropes was realized by heat treatment and introducing LaNi5compound. It was found that the alloy annealed within 1073–1223 K kept (La,Mg)2Ni7phase and obvious crystal transformation of 2H- into 3R-type occurred as annealing temperature reached 1223 K. Electrochemical study showed similar discharge capacity and degradation behavior for La0.75Mg0.25Ni3.5alloys with different amounts of 2H- and 3R-type allotropes whileHRDwas promoted by increasing 3R-type phase abundance. Introducing LaNi5into La0.75Mg0.25Ni3.5alloy increased 3R- to 2H-type phase ratio and led to an additional plateau inP–Cisotherms. LaNi5introduction improvedHRD, however it accelerated cycling degradation. Rietveld analysis indicated that after hydrogenation, the cell expansion of 2H- and 3R-type (La,Mg)2Ni7phase was similar while the cell expansion of LaNi5phase was smaller than that of (La,Mg)2Ni7phase. This caused discrete cell expansion between (La,Mg)2Ni7and LaNi5phases, leading to severe pulverization and oxidation.
登录
查看更多内容
影响因子：
1.5
作者：
A. Albinati;B. T. M. Willis
通讯作者：
A. Albinati;B. T. M. Willis
影响因子：
6.2
作者：
Yongfeng Liu;H. Pan;M. Gao;Y. Lei;Qidong Wang
通讯作者：
Yongfeng Liu;H. Pan;M. Gao;Y. Lei;Qidong Wang
影响因子：
7.2
作者：
H. Pan
通讯作者：
H. Pan
影响因子：
3.7
作者：
Qingan Zhang;M. Fang;T. Si;Fang Fang-Fang;Dalin Sun;L. Ouyang;Min Zhu
通讯作者：
Qingan Zhang;M. Fang;T. Si;Fang Fang-Fang;Dalin Sun;L. Ouyang;Min Zhu
影响因子：
7.2
作者：
Z. Liu;Xiaobo Yan;N. Wang;Y. Chai;D. Hou
通讯作者：
Z. Liu;Xiaobo Yan;N. Wang;Y. Chai;D. Hou