An Areal-Energy Standard to Validate Air-Breathing Electrodes for Rechargeable Zinc–Air Batteries

Abstract

Rechargeable zinc–air batteries may become safe, sustainable, low-cost, and energy-dense alternatives to Li-ion batteries for many applications, but problems associated with today's air-breathing electrodes limit zinc–air performance. To overcome this challenge, researchers have investigated hundreds of air-breathing electrode variations over the last decade. Unfortunately, the efficacy of these variations remains ambiguous due to nonstandardized cycling protocols that map to areal-energy values spanning five orders of magnitude. To compete with Li-ion batteries, researchers should cycle zinc–air cells at 35 mWh cmgeo−2, but only 8, of the 100 publications reviewed here, breach this threshold. Once the community cycles zinc–air cells at the proposed areal energy and better understands failure mechanisms, lab-scale results will translate to practical advancements.