Effect of mechanical milling on electrochemical properties of Ti ₄₅Zr_38xNi_17+x (x = 0, 8) quasicrystals produced by rapid-quenching

The effect of mechanical milling on the discharge performance of electrodes consisting of Ti₄₅Zr_38-xNi_{17+ x} (x = 0, 8) quasicrystals, which were produced by a rapid-quenching, was investigated at room temperature in three-electrode cell set-up. All of the obtained ribbons were identified to contain mostly icosahedral (i) quasicrystal phase (i-phase). The measured discharge capacity for Ti₄₅Zr ₃₀Ni₂₅ material was higher than the one for Ti ₄₅Zr₃₈Ni_17. The maximum discharge capacity equal 86 mA h g^-1 was achieved for Ti₄₅Zr ₃₀Ni₂₅, which was mechanically milled for 15 h. This value was obtained at the third discharge process. The recorded discharge performance was quite stable on cycling up to 30 cycles for Ti₄₅Zr ₃₈Ni₁₇ material, but slight decrease after 15th cycle was observed for Ti₄₅Zr₃₀Ni₂₅ phase. It should be highlighted that the quasicrystal i-phase remained stable also after 25 h of mechanical milling for both studied materials. However, a formation of (Ti, Zr)H₂ hydride phase was observed after charge/discharge cycles for both of the materials.