Microstructure and Electrochemical Properties of La0.75Mg0.25Ni3.5(TiNi3)0.1 Hydrogen Storage Alloys
La0.75Mg0.25Ni3.5(TiNi3)0.1 alloys were prepared by induction melting followed by annealing treatment at 1173Kand 1h,2h,5h,12h,respectively. Alloys structure and electrochemical properties have been studied systematically by X-ray diffraction(XRD) with the Rietveld methold , Electron probe micro-analyzer (EPMA)and electrochemical experiments. Alloys structure analyses showed that all of the alloys mainly consisted of complex phases such as LaNi5 phase (CaCu5-type,SG: P6/mmm), (La ,Mg)2Ni7 phase (Ce2Ni7-type, SG: P63/mmc)and (La,Mg)2Ni7 phase(Gd2Co7-type,SG: R-3m). Annealed treatment was benefited to the formation of (La ,Mg)2Ni7 phase. Annealed time was imprtant for the alloys microstructure, for the alloys with annealed for 1 hour,the microstructure between main phase and TiNi3 phase was three-dimensional network,with the annealed time incresed,the TiNi3 phase became reunite. The microstructure of three-dimensional network was useful for the electrochemical cycle stability of alloys electrodes(S100=87%).
Jinglong Bu, Pengcheng Wang, Liqun Ai, Xiaoming Sang, Yungang Li
A. Q. Deng et al., "Microstructure and Electrochemical Properties of La0.75Mg0.25Ni3.5(TiNi3)0.1 Hydrogen Storage Alloys", Advanced Materials Research, Vols. 287-290, pp. 2526-2530, 2011