Aluminum and Zinc Metal Anode Batteries

Aluminum and zinc metal are expected to be anode active materials with high volumetric capacity for future secondary batteries. Theoretical volumetric capacities for Al and Zn are 5854 and 8046 mAh cm−3, respectively. These metal anodes are usually handled in the Lewis acid-base type ionic liquid (IL) electrolytes with Al or Zn salts, e.g., AlCl3–1-ethyl-3-methylimidazolium chloride ([C2mim]Cl) and ZnCl2–[C2mim]Cl. However, the appropriate metal salt composition in the ILs is required to yield the metal anode reactions related to the charge-discharge process. These IL systems are good choices for conducting the studies on the Al and Zn metal anode battery because of adequate carrier anion density and very high coulomb efficiency for the anode reaction. Interestingly, their anode reactions are controlled by the anionic species, not cationic species, Al3+ and Zn2+. Meanwhile, cathode active materials leave much to be improved, but some promising ones have recently been reported. The most important thing is that the full cells fabricated using the findings behave like commonly used secondary batteries, suggesting that these battery systems are worthy of careful study and possess tremendous potential to be one of the next-generation batteries.