Dergi makalesi Açık Erişim

Synthesis of La-2(Ni1-xCox)(7) (x=0.05, 0.1, 0.2) Hydrogen Storage Alloys by the Electro-Deoxidation Technique

2015    Anik, Mustafa; Aybar, Alanur Binal; Hatirnaz, Nurten Basak; Ozdemir, Duygu

La-2(Ni1-xCox)(7) (x = 0.05, 0.1, 0.2) alloys were synthesized directly from sintered mixture of La2O3 + NiO + CoO in the molten CaCl2 electrolyte by the electro-deoxidation method at 850 degrees C and the electrochemical hydrogen storage characteristics of the synthesized alloys were observed. Sintering (at 1200 degrees C for 3 h) converted the hygroscopic La2O3 (by the reaction with NiO) into the non-hygroscopic LaNiO3, La3Ni2O6.5 and La4Ni3O9 depending on the Co content of the oxide mixture. The X-ray diffraction peaks indicated that La2NiO4 was the main La-Ni-0 phase formed as a result of partial reduction or dissociation reaction to initiate the LaNis phase formation. The target La2Ni7 phase formed much later than LaNis phase probably due to the sluggish reduction of LaOCI. It was observed that La-2(Ni1-xCox)(7) (x = 0.05, 0.1, 0.2) alloys had promising discharge capacities changed between 227 mA h g(-1) (La-2(Ni0.95Co0.05)(7)) and 332 mA h g(-1) (La-2(Ni0.8Co(0.2))(7)) depending on the alloy Co content. This work clearly indicated that the electro-deoxidation was very effective method in the synthesis of the hydrogen storage materials. (C) 2015 The Electrochemical Society. All rights reserved.