Breaking the Passivity Wall of Metals: Exempli Gratia Non-Aqueous Ti–Air Battery

Abstract

A new multivalent metal–air battery employing Titanium (Ti) as active material in EMIm(HF)2.3F room temperature ionic liquid electrolyte is introduced. Ti metal is highly attractive as it is a light metal that can possibly transfer up to 4 electrons. The electrochemical behavior of Ti is known for its passivity in various media. Here, we evaluated the electrochemistry of Ti in EMIm(HF)2.3F with potentiodynamic polarization and galvanostatic discharge experiments. Ti–air battery could successfully be operated under relatively high current densities (up to 0.75 mA cm−2) with an average cell voltage of 1-1.2 V, yielding up to a discharge capacity of 66 mAh cm−2. When its full potential is harvested, such a metal–battery holds a unique potential to be the only metal with 4 electrons transfer during its discharge.

Keywords: metal-air battery, titanium-air, Non-aqueous electrolyte, passivity