Phase structure and electrochemical properties of non-stoichiometric La_(0.7)Ce_(0.3)(Ni_(3.65)Cu_(0.75)Mn_(0.35)Al_(0.15)(Fe_(0.43)B_(0.57))_(0.10))_x hydrogen storage alloys  

作　　者：范燕平 刘宝忠 张宝庆 吉力强 张志 

机构地区：[1]School of Physics and Chemistry,Henan Polytechnic University [2]School of Materials Science&Engineering,Henan Polytechnic University [3]Inner Mongolia Rare Earth Ovonic Metal Hydride Co.,Ltd

出　　处：《Journal of Rare Earths》2012年第12期1249-1254,共6页稀土学报（英文版）

基　　金：Project supported by National Natural Science Foundation of China (51001043);Program for New Century Excellent Talents in University (NCET2011);China Postdoctoral Science Special Foundation (201104390, 20100470990);Program for Innovative Research Team (in Science and Technology) in the University of Henan Province (2012IRTSTHN007);Baotou Science and Technology Project (2011J1003);and the Doctoral Foundation of Henan Polytechnic University (B2010-13)

摘　　要：Phase structure and electrochemical characteristics of Co-free La0.7Ce0.3（Ni3.65Cu0.75Mn0.35Al0.15（Fe0.43B0.57）0.10）x （0.90≤x≤1.10） alloys were investigated. When x was 0.90, the alloy was composed of LaNi5, La3Ni13B2 and Ce2Ni7 phases. The Ce2Ni7 phase disappeared, and the abundant of La3Ni13B2 phase decreased when x increased to 0.95. When x was 1.00 or higher the alloys consisted of LaNi5 phase. The lattice parameter a and the cell volume V of the LaNi5 phase decreased, and the c/a ratio of the LaNi5 phase increased with x value increasing. Maximum discharge capacity of the alloy electrodes first increased and then decreased with x value increasing from 0.90 to 1.10, and the highest value was obtained when x was 1.00. High-rate dischargeability at the discharge current density of 1200 mA/g increased from 50.7% （x= 0.90） to 64.1% （x=1.10）. Both the charge-transfer reaction at the electrode/electrolyte interface and the hydrogen diffusion in the alloy were responsible for the high-rate dischargeability. Cycling capacity retention rate at 100^th cycle （$10o） gradually increased from 77.3% （x= 0.90） to 84.6% （x= 1.10）, which resulted from the increase in Ni content and the c/a ratio of the LaNi5 phase with x value increasing.Phase structure and electrochemical characteristics of Co-free La0.7Ce0.3（Ni3.65Cu0.75Mn0.35Al0.15（Fe0.43B0.57）0.10）x （0.90≤x≤1.10） alloys were investigated. When x was 0.90, the alloy was composed of LaNi5, La3Ni13B2 and Ce2Ni7 phases. The Ce2Ni7 phase disappeared, and the abundant of La3Ni13B2 phase decreased when x increased to 0.95. When x was 1.00 or higher the alloys consisted of LaNi5 phase. The lattice parameter a and the cell volume V of the LaNi5 phase decreased, and the c/a ratio of the LaNi5 phase increased with x value increasing. Maximum discharge capacity of the alloy electrodes first increased and then decreased with x value increasing from 0.90 to 1.10, and the highest value was obtained when x was 1.00. High-rate dischargeability at the discharge current density of 1200 mA/g increased from 50.7% （x= 0.90） to 64.1% （x=1.10）. Both the charge-transfer reaction at the electrode/electrolyte interface and the hydrogen diffusion in the alloy were responsible for the high-rate dischargeability. Cycling capacity retention rate at 100^th cycle （$10o） gradually increased from 77.3% （x= 0.90） to 84.6% （x= 1.10）, which resulted from the increase in Ni content and the c/a ratio of the LaNi5 phase with x value increasing.

关 键 词：hydrogen storage alloy NON-STOICHIOMETRY phase structure electrochemical property Ni/MH batteries rare earths 

分 类 号：TG139.7[一般工业技术—材料科学与工程] TG148[金属学及工艺—合金]