LAUSR

Abstract (La 1 − x Mg x ) 2 (Ni 0.8 Co 0.2 ) 7 ( x  = 0.125, 0.25, 0.5) alloys were synthesized from the sintered mixture of La 2 O 3  + NiO + CoO + MgO in the molten CaCl 2 electrolyte at 750 °C and the electrochemical hydrogen storage capacities of the synthesized alloys were measured. Non-hygroscopic LaNiO 3 phase formed during sintering (at 1200 °C for 2 h) as a result of the reaction of hygroscopic La 2 O 3 with NiO. Another sinter product was Mg 0.4 Ni 0.6 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 5 which formed upon reduction of La 2 NiO 4 phase. Increase in Mg content caused formation of La 1.5 Mg 0.5 Ni 7 phase in the alloy structure and the presence of this phase improved the hydrogen storage performance of the electrodes. It was observed that (La 1- x Mg x ) 2 (Ni 0.8 Co 0.2 ) 7 ( x  = 0.125, 0.25, 0.5) alloys have promising discharge capacities change between 319 mAh/g and 379 mAh/g depending on the alloy Mg content.