Rechargeable Zinc Air Batteries and Highly Improved Performance through Potassium Hydroxide Addition to the Molten Carbonate Eutectic Electrolyte

Abstract

© The Author(s) 2018. The zinc air battery has been regarded as an efficient solution to renewable energy storage applications in the next generation. Zinc air chemistries are promising, though great challenges still remain to utilize their high energy, optimize efficiency and high discharge rate. Here, we demonstrate an improved zinc air battery by replacing NaOH, used in our previous study, with KOH as an additive to the molten Li0.87Na0.63K0.50CO3 eutectic electrolyte. Cycling tests showed a very stable performance through 150 charge-discharge cycles, exhibiting high coulombic efficiency (94%) and an average discharge potential of ∼1.08 V when charged at a constant current of 75 mA and discharged over a constant 100 load to 0.8 V cutoff at 550◦C. Moreover, rate tests revealed a good performance even at high rates of cycling, maintaining a coulombic efficiency of over 90% while at 7.3 C. These results show marked improvements in the field of rechargeable zinc air batteries.