Preparation and electrochemical hydrogen storage properties of Ti49Zr26Ni25 alloy covered with porous polyaniline

Abstract

A facile saturated solution synthesis method is used to obtain the porous polyaniline (P-PANI). The materials exhibit unique sea urchin-like morphology and special porous structure. Ti49Zr26Ni25 quasicrystal is fabricated via mechanical alloying followed by annealing treatment. Different amounts of P-PANI are coated on the surface of hydrogen storage alloy by ball milling. For comparison, Ti49Zr26Ni25 alloy doped with conventional PANI (C-PANI) is also prepared. The electrochemical characterizations of the composites are conducted in the standard tri-electrode system. Ultimately, the P-PANI coated Ti49Zr26Ni25 electrode shows preferable performance compared with the C-PANI modified alloy (230.6 mAh/g) and original alloy (209.3 mAh/g). As the additive content of P-PANI is 6 wt%, a maximum discharge capacity of 258.7 mAh/g is obtained. Furthermore, the cycle stability and high-rate dischargeability of the electrodes are also enhanced. The P-PANI materials with distinctive morphology and unique porous structure can not only improve the electrocatalytic activity of polyaniline but also increase the specific surface area of Ti49Zr26Ni25 alloy. The P-PANI can further facilitate the hydrogen diffusion, expedite the charge transfer in/on the alloy and improve the corrosion resistance, thus enhancing the electrochemical performance and reaction kinetics of the hydrogen storage alloys.