The structure and electrochemical characteristics of La0.7Mg0.3Ni2.875Co0.525Mn0.1-boron composite was studied systematically. The AB3 type hydrogen storage alloys La0.7Mg0.3Ni2.875Co0.525Mn0.1 were successfully synthesized by means of inter-media alloy La2Mg17. The alloys were composited with boron at different weight rate. From the XRD analyses, each alloy of this series is mainly composed of (La,Mg)Ni3 phase and the LaNi5 phase, and the phase abundance of each phase varies with the boron weight rate, moreover, after composition, the c and cell volumes of (La,Mg)Ni3 phase increase, and the LaNi5 phase keep the same, which indicate that the boron may enter (La,Mg)Ni3 phase. The electrochemical studies show that the maximum discharge capacity of the composites decreases, but the cycling life improved. And the high rate discharge ability and exchange impendence spectroscopy (EIS) of the AB3 alloys and its composite were also studied.
LIU Yi WANG Yijing XIAO Lingling CAO Jiansheng JIAO Lifang FENG Yan YUAN Huatang
The La0.8Mg0.2Ni2.4Mn0.10Co0.55Al0.10 alloy was prepared by induction melting. The structural and morphological characterizations were performed by means of X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical measurements were performed using LAND and CHI 660b electrochemical workstation. The main phases of the alloy were LaNi5 and (La,Mg)Ni3. After annealing, the maximum discharge capacity, cycle stability and high rate dischargeability (HRD) were improved obviously. The maximum discharge capacity reached 373.80 mAh/g (T=1173 K), the C100/Cmax(%) was 72.63% (T=1173 K), and the value of HRD reached 51.8% at a discharge current density of 1150 mA/g (T=1173 K). The cyclic voltammetry (CV) and potentiodynamic polarization were also studied.
