The microstructure and electrochemical properties of Mn-doped La-Y-Ni-based metal-hydride electrode materials

The structural characteristics and electrochemical performances of superlattice La5.42Y18.50Ni76.08-xMnx (X = 0, 2, 4, and 6) metal-hydride electrodes were investigated. La5.42Y18.50Ni76.08 alloy is composed of LaY2Ni9, Y2Ni7, and La2Ni7 phases, while the amount of AB(3)-type phase increases due to the increasing substitution amount of Ni by Mn. The mechanisms on the related electrochemical thermodynamics and kinetics were investigated systematically. Compared with La5.42Y18.50Ni76.08 alloy, the maximum discharge capacity of La5.42Y18.50Ni70.08Mn6 alloy increased from 275.2 mAh g(-1) to 379.6 mAh g(-1) and the discharge capacity after 30 cycles increased from 155.0 mAh g(-1) to 281.1 mAh g(-1), which contribute to the increase of the amount of AB(3)-type phase as well as the ameliorated structural stability through the substitution of Mn for Ni. (C) 2018 Elsevier Ltd. All rights reserved.