International Journal of Hydrogen Energy, Vol.45, No.20, 11675-11685, 2020
Preparation and electrochemical hydrogen storage properties of Ti49Zr26Ni25 alloy covered with porous polyaniline
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. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.