摘要
采用低温水热法一步制备出氧化物MO(M=Cu,Fe)与储氢合金La Ni_(3.81)Mn_(0.30)Co_(0.79)Al_(0.10)(AB_5合金)的复合材料.低温水热处理对合金的晶体结构没有影响,SEM-EDS照片显示氧化物均匀附着在合金颗粒表面.合金电极的电化学测试表明,Fe_2O_3@AB_5电极的最大放电容量为332.70 m Ah/g,Cu O@AB_5电极为342.61 m Ah/g,均大于未经处理的AB_5合金电极的323.62 m Ah/g.在1 500 m A/g的放电电流下,Fe_2O_3@AB_5电极和Cu O@AB_5电极的高倍率放电(HRD)分别比未处理的合金电极高13.61%和6.63%.在充放电循环250周期后,电极的容量保持率分别为S_(250)(Fe_2O_3@AB5)=63.17%,S250(Cu O@AB_5)=47.81%,S_(250)(AB_5)=61.33%.复合材料电极电化学性能改善的原因可能是生长在储氢合金表面的过渡金属氧化物具有催化活性并参与了电极充放电反应时的氧化还原反应.
Oxides （copper oxide, iron oxide） as additives were used to surface modification on hydro-gen storage alloy surface. One-step low-temperature hydrothermal method was used to improve the electrochemical properties including the maximum discharge capacity, charge retention rate and cycle lifeof LaNi3.81Mn0.30Co0.79Al0.10 alloy （a AB5 -type hydrogen storage alloy）. The alloy is still LaNi5 phase after low temperature hydrothermal method. SEM-EDS shows that the oxide particles are attached to thealloy surface after the treatment. The maximum discharge capacity of Fe2O3＠ AB5 is 332.70 mAh / g,CuO＠ AB5 is 342.61 mAh / g which is higher than 323.62 mAh / g of unmodified AB5 hydrogen storagealloy. The HRD of Fe2O3＠ AB5 and CuO＠ AB5 is 13.61% and 6.63% higher than untreated alloy electrodes, respectively. After 250 cycles of charging / discharging process, the capacity retention rate isS250= 63.17% （Fe2O3＠ AB5）, S250= 47.81% （CuO＠ AB5） and S250= 61.33% （AB5）. The cyclestability of Fe2O3＠ AB5 electrode is the best. The reason for the improvement of electrochemical properties of composite materials may be the catalytic activity of oxides and the involvement in the charging / discharging process of the electrodes.
出处
《化学研究》
CAS
2018年第1期84-89,共6页
Chemical Research
基金
国家自然科学基金(51502233)
西安工业大学校长基金(XAGDXJJ5011)
关键词
过渡金属氧化物
储氢合金
表面修饰
电化学性能
transition metal oxide
hydrogen storage alloys
surface treatment
electrochemical properties
