Study On Negative Electrode Materials Of "Laves Phase Related BCC Solid Solution" Alloys

"Laves phase related BCC solid solution" is a new concept, and is also called the third generation of hydrogen storage alloy, the hydrogen capacity of the new Ti-based BCC alloy developed from it has reached to 2.2mass%. Through the TEM microstructure observation of the area adjacent to the BCC/C14 interface in TiMnV, a very fine lamellar structure (10nm thickness) was found. The composition of this adjacent interface phase was Ti1.0Mn0.9V1.1. P-C-T diagrams of Ti1.0Mn0.9V1.1 shows this kind of alloys have high capacity and wide plateau region. These are remarkable improvements over the conventional BCC hydrogen absorbing alloy, because, in general, conventional BCC alloy such as TiV can not desorb hydrogen under ambient conditions. Based on these research results, in this paper, some work on Ti1.0Mn0.9V1.1 has been done.The microstructure and the electrochemical characteristics of Ti1.0Mn0.9-xV1.1Nix, Ti1.0Mn0.9V1.1-xNix, Ti1.0(Mn0.9V1.1)1.0-xNi2x, Ti1.0-xZrxMn0.5 V1.1Ni0.4 and Ti1.0(Mn0.9V1.1)0.7-xCr2xNi0.6 alloys were investigated by means of XRD, SEM and electrochemical measurements. It is shown that these alloys are all composed of BCC main phase and some C14 Laves phase; the addition of Ni substitution for Mn improves the electrochemical activities of the alloys, the addition of Zr substitution for Ti decreases the performance of alloys and the addition of Cr improves cycle life of the alloys. Two kinds of composite alloy was prepared by ball-milling Ti1.0V1.1Mn0.7Ni0.2+5mass% LaNi5 and Ti1.0V1.1Mn0.3Ni0.6, and their electrochemical characteristics were performed, it was found that the dischargeability of the alloy electrodes was dramatically increased by surface alloying and ball-milling.The innovation of this work: To make Ti1.0Mn0.9V1.1 to have electrocatalyst activity and the microstructure and the electrochemical characteristics of Ti1.0Mn0.9V1.1 based alloys were studied first time. Ti1.0Mn0.9V1.1 based alloys are probably negative electrode materials for the Ni/MH battery at high temperature.