Breaking the passivity wall of metals: Exempli gratia non-aqueous Ti-air battery

A new multivalent metal-air battery employing Titanium (Ti) as active material in EMIm(HF)2.3F room tem-perature 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.