Electrochemical properties of sealed Ni?MH batteries using nanocrystalline TiFe-type anodes

Abstract

Mechanical alloying (MA) process was introduced to produce nanocrystalline TiFe0.25Ni0.75 and TiNi alloys. XRD analysis showed that, firstly, after 20 h of milling, the starting mixture of the elements had transformed into an amorphous phase and, secondly, the annealing in high purity argon at 700 °C for 0.5 h led to formation of the CsCl-type structures with a crystallite size of about 25 nm. These materials were used as negative electrodes for sealed nickel–metal hydride (Ni–MH) batteries. The results show that the sealed battery using the nanocrystalline TiFe0.25Ni0.75 alloy has about 1.5 times the capacity of the TiNi one.