Preparation and Electrochemical Property of Combined Electrode of LaMg2Ni2.7Co2.1Mn2.7Cu1.5 Coated with TiO2

Abstract:

LaMg2Ni2.7Co2.1Mn2.7Cu1.5 hydrogen storage alloy was synthesized by the method of co-precipitation and reduction diffusion, and TiO2 powder by hydrothermal method, then the alloy was coated with TiO2 powder to prepare composite electrode. The structures of the hydrogen storage alloy and TiO2 powder were characterized by X-ray diffraction. The electrochemical performances of composite electrode were tested by battery tester under two different conditions. In one condition, the electrode was kept in a dark box. In another condition, the electrode was kept under radiation of a ultraviolet lamp. The results show that in dark box the activation performance and maximum discharge capacity of composite electrode are not as good as that of original alloy electrode that is not coated with TiO2, but the cyclic stability becomes better. In light condition, the electrochemical performances of the composite electrode, including activation performance, maximum discharge capacity and cyclic stability, become better than that of original alloy electrode. For example, the maximum discharge capacity of composite electrode (coated with 20% TiO2) increases 25mA?h?g-1 compared with original alloy electrode. They are also better than that in dark box. The results of this paper illustrate that combination of LaMg2Ni2.7Co2.1Mn2.7Cu1.5 hydrogen storage alloy with TiO2 by surface coating method is effective to improve electrochemical performances of the alloy.

Key words:AB3 type hydrogen storage alloys; TiO2; electrochemical property; composite electrode