Evaluation of testing factors In zinc–air battery, the losses in activation, ohm and concentration polarization areas together determine the final performance [44, 46]. The activation polarization is mainly related to the kinetics of electrocatalytic redox reactions in cathode.
Battery configuration is extremely crucial for metal–air batteries as they are prone to exhibit deteriorated electrochemical performance because of the electrolyte leakage due to their mandatory partially open-cell design to let in the atmospheric oxygen [ 3 ].
These highly active catalysts have improved the peak power density of zinc–air battery – the most important performance indicator, to > 200 mW cm −2 [28, 29]. In laboratories, rotating disk electrode (RDE) method is traditionally used to screen electrocatalysts for zinc–air batteries.
By fitting the polarization curves of the zinc–air batteries, we reveal the effect of testing parameters (electrode distance, electrolyte concentration, and oxygen flux) and preparation of catalysts ink on the activation, ohm, and concentration polarizations of the zinc–air battery.
Notably, in 2016, an Al–air battery weighing 100 kg was fabricated and shown to be capable of extending the range of an electric vehicle to over 3000 km. Many research groups have been dedicated to enhancing the capacity and lifetime of Al–air battery systems however there are still many hurdles to overcome. Fig. 2.
Zinc–air batteries provide a great potential for future large-scale energy storage. We assess the test factors that mainly affect the measured power density of the zinc–air battery.