Effect of Li atom infiltration by the way of electro-osmosis on electrochemical properties of amorphous Mg65Ni27La8 alloy used as negative electrode materials for the nickel-metal hydride secondary batteries

摘要

The Mg65Ni27La8 alloy is synthesized by arc melting and subsequent melt-spinning technique, then Li atoms are infiltrated into this alloy material by the way of electroosmosis. The structure of the above two kinds of alloys is characterized by X-ray diffraction and scanning electron microscopy. Furthermore, electrochemical properties of two alloy electrodes are investigated systematically. Electrochemical studies indicate that negative electrode prepared by the Mg65Ni27La8-Li alloy possesses the best discharge capacity (693.8 mAh/g) and cycling stability (83.2% after 30 cycles) at a current density of 30 mA/g, which is higher than that of Mg65Ni27La8 alloy electrode. Compared with the Mg65Ni27La8-Li alloy, the Mg65Ni27La8 alloy shows better discharge capacity of 571.9 mAh/g and lower cycling stability (70.2% after 30 cycles), which explains the structure evolution of amorphous ribbon that is responsible for the decay of discharge capacity. In addition, we also study the electrochemical reaction kinetics of Mg65Ni27La8-Li alloy electrodes. (C) 2015 Elsevier B.V. All rights reserved.