Direct synthesis of La-Mg-Ni-Co type hydrogen storage alloys from oxide mixtures

(La;Mg;);(Ni;Co;);（x = 0.125, 0.25, 0.5） alloys were synthesized from the sintered mixture of La;O;+ Ni O + Co O + Mg O in the molten CaCl;electrolyte at 750 °C and the electrochemical hydrogen storage capacities of the synthesized alloys were measured. Non-hygroscopic LaNiO;phase formed during sintering（at 1200 °C for 2 h） as a result of the reaction of hygroscopic La;O;with NiO. Another sinter product was Mg;Ni;O phase. Both mixed oxide sinter products facilitated the La-Ni and Mg-Ni phase formations. X-ray diffraction peaks indicated that the first stable phase appeared in the alloy structure was LaNi;which formed upon reduction of La;NiO;phase. Increase in Mg content caused formation of La;Mg;Ni;phase in the alloy structure and the presence of this phase improved the hydrogen storage performance of the electrodes. It was observed that(La;Mg;);(Ni;Co;);（x = 0.125, 0.25, 0.5） alloys have promising discharge capacities change between 319 m Ah/g and 379 m Ah/g depending on the alloy Mg content.