Effect of Li on structure and electrochemical hydrogen storage properties of Ti55V10Ni35 quasicrystal alloy

Abstract

The Ti55V10Ni35 quasicrystal ribbons are synthesized by arc melting and subsequent melt-spinning technique and then Li atoms are infiltrated into this quasicrystal material by the way of electroosmosis. X-ray diffraction results indicate that the pristine quasicrystal Ti55V10Ni35 mainly consists of the icosahedral quasicrystal (I-phase), V-based solid solution phase with BBC structure and face centered cubic (FCC) phase with Ti2Ni-type structure. After infiltrating some amount of Li atoms into Ti55V10Ni35 quasicrystal lattice voids at different electroosmosis current density (A/mg) of 0.3, 0.6 and 0.9 respectively, phase structure investigations show that the main phase structures do not change greatly except for the additional lithium phase, which demonstrates that Li does not destroy the phase structure of Ti55V10Ni35 quasicrystal. Ti55V10Ni35 alloy shows the best discharge capacity is 219.8 mAh g−1 at a current density of 30 mA g−1. The negative electrode made by Ti55V10Ni35–Li quasicrystal alloys (Li atoms are infiltrated into Ti55V10Ni35 quasicrystal alloy at different the electroosmosis current density (A/mg) of 0.3, 0.6 and 0.9 has a maximum discharge capacity of 257.7 mAh g−1, 301.8 mAh g−1 and 238.7 mAh g−1 at a discharge current density of 30 mA g−1, respectively. And the high rate discharge ability of alloy electrodes is higher than that of Ti55V10Ni35 quasicrystal alloy at 240 mA g−1. The Effect of Li on structure of Ti55V10Ni35 quasicrystal has been discussed by measuring the place, mass ratio and chemical state that Li infiltrated into quasicrystal Ti55V10Ni35 lattice. In addition, the electrochemical reaction kinetics of Ti55V10Ni35–Li quasicrystal alloy electrodes is also studied by measuring both the electrochemical impedance spectroscopy and hydrogen diffusion coefficient.