Highly Efficient Thin Zinc Air Batteries

Zinc air batteries have been recognized as an important type of energy storage devices due to their high energy density and relatively low cost. However, unsatisfactory cycle life limits their applications. Herein, a novel structure of zinc air batteries was demonstrated, which possesses a small distance (0.11 mm) between two electrodes, great exposure to air, and small thickness (0.2 mm for each) of gas diffusion layer and catalyst layer. Even using the commercial Co3O4 catalyst without modification, such a structured thin cell reached the highest discharge power density of 89.0 mW/cm2 at 92.3 mA/cm2 and 1.0 V in 6 M KOH and 0.2 M Zn(CH3COO)2. Furthermore, it also survived 400 charge-discharge cycles at 15 mA/cm2 and exhibited almost constant cell voltage gap of ∼1.2 V, with mild Zn anode deformation. These findings suggest enormous potential and research value of ultrathin zinc air batteries.