Enhanced electrochemical hydrogen storage properties of Ti49Zr26Ni25 quasicrystal alloy by doping with CO2-activated porous graphene

Abstract

Ti49Zr26Ni25 quasicrystal alloy was fabricated via mechanical alloying and subsequent annealing. In order to enhance the electrocatalytic activity and conductivity of Ti49Zr26Ni25, the porous graphene (PoRGO) material was synthesized by a facile CO2 activation treatment of reduced graphene oxide (RGO). The composites of Ti49Zr26Ni25 doping with different amount of PoRGO were manufactured through ball milling. During the electrochemical hydrogen storage test, the porous Ti49Zr26Ni25 + PoRGO exhibited higher discharge capacity than Ti49Zr26Ni25 + CRGO and conventional Ti49Zr26Ni25 alloy. Moreover, the additive amount of PoRGO had great influence on the electrochemical properties of Ti49Zr26Ni25. Eventually, 5 wt% PoRGO modified Ti49Zr26Ni25 alloy electrode achieved a highest discharge capacity of 270 mAh/g. The large specific surface area and distinctive porous structure of porous graphene could offer more electrochemical active sites and facilitate the hydrogen diffusion. In the meantime, the cycling stability, high-rate dischargeability (HRD) and kinetic properties of Ti49Zr26Ni25 were also improved after PoRGO loading. Consequently, porous graphene can be potential used as the dopant for the modification of hydrogen storage alloys.