摘要
为了提高La_(0.94)Mg_(0.06)Ni_(3.49)Co_(0.73)Mn_(0.12)Al_(0.20)合金的性能,研究了氟化处理对其电化学性能的影响。X射线衍射和扫描电镜分析表明:氟化处理后,合金的相组成发生改变,有新相Mg F2生成;合金的表面有一层Mg F2颗粒。电化学测试表明:当NH4F浓度为0.3 mol/L时,合金电极的最大放电容量(Cmax)从346.4 m Ah/g提高到378.0 m Ah/g,容量保持率(S50)从69.5%提高到74.3%,交换电流密度由122.3 m A/g提高到188.5 m A/g,极限电流密度由891.7 m A/g提高到1162.1 m A/g,腐蚀电位由-0.895 V提高到-0.849 V,电化学反应阻抗减小。
In order to improve the electrochemical properties of La0.94Mg0.06Ni3.49Co0.73Mn0.12Al0.20 hydrogen storage alloy,the fluorination treatment was adopted. The results by X-ray diffraction and scanning electron microscopy showed that the phase composition of the alloy changed after fluorination treatment,a new phase Mg F2 formed,and there were some particles of Mg F2 on the surface of the alloy.Electrochemical studies displayed that when the concentration of NH_4F was 0. 3 mol/L,the maximum discharge capacity Cmaxof the alloy electrode increased from 346. 4 mAh/g to 378. 0 mAh/g,the capacity retention rate S50 improved from 69. 5% to 74. 3%,the exchange current density increased from 122. 3 mA/g to 188.5 mA/g,the limiting current density improved from 891. 7 mA/g to 1 162. 1mA/g,the corrosion potential improved from- 0.895 V to-0.849 V,and electrochemical reaction impedance reduced.
出处
《精细化工》
EI
CAS
CSCD
北大核心
2016年第8期867-871,共5页
Fine Chemicals
基金
国家自然科学基金(NSFC11364013)
广西矿冶与环境科学实验中心项目(KH2012YB002)~~
关键词
储氢合金
氟化处理
表面处理
电化学性能
功能材料
hydrogen storage alloy
fluorination treatment
surface modification
electrochemical properties
functional materials
