Transition Metal-Based High Entropy Alloy Microfiber Electrodes: Corrosion Behavior and Hydrogen Activity

This contribution reveals ultra-high corrosion resistance of high entropy alloys (HEAs), i.e. Ti20Zr20Nb15V15Hf15Ta15 of 1.85 mu m yr(-1) in alkaline environment, adverting their use for battery/fuel cell components. Formation of several nanometers passive oxide layer confirmed by scanning transmission electron microscopy accounts for corrosion resistance which increases with TiOx content. Cathodic Tafel slope of 67 mV dec(-1) and large transfer coefficient of 0.82 obtained for Ti20Zr20Nb20V20Ta20 suggest its use for hydrogen electrocatalysis. High amounts of hydrogen storage, 1.7 wt% in Ti25Zr25Nb15V15Ta20, were confirmed by gas-solid reactions. This HEA also has high corrosion resistance in acidic and saline environments ideal for coatings and surgical tools/implants.