Structure and electrochemical hydrogen storage properties of Ti-Fe-Mn alloys for Ni-MH accumulator applications

In this study, TiFe0.90Mn0.10 and TiFe0.95-xMnx (x = 0.05, 0.15) with excess in titanium powder samples were synthesized through mechanical alloying (MA) at room temperature under argon atmosphere. The micro-structural and morphological properties of these powder alloys were investigated by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and transmission electron microscopy (TEM). The effects of the substitution of Fe by Mn and the excess of Ti on the electrochemical properties were studied through the galvanostatic, potentiostatic and potentiodynamic polarization methods. The XRD and SEM analysis confirm the presence of the amorphous phase for all the samples. The sample with the lowest Mn content (x = 0) and excess in titanium has the highest maximum discharge capacity and reversibility (224 mAh g−1 and 368 mV). A correlation between the evolution of different electrochemical parameters, cycling, kinetic and redox was observed during the cycling. [Display omitted] •The micro-structural and morphological properties of the Ti-Fe-Mn powder alloys were investigated.•The effect of Fe substitution by Mn and the excess in Ti on the electrochemical properties were studied.•All the electrodes reached their maximum capacities at the first cycle.•A good correlation between the polarization and cycling stability was observed.•The alloy milled with excess in Ti shows the higher value of maximum discharge capacity and Nernst potential.