Zinc systems | Zinc–air

Abstract

A zinc–air battery is one of metal–air batteries with high energy densities, consisting of safe, environmentally benign and low-cost materials for both electrodes and electrolyte compounds. The primary zinc–air battery shows flat voltage at around 1.2V and offer specific and volumetric energy densities of around 500Whkg−1 and 1000WhL−1. Widespread commercial applications of the primary zinc-air alkaline batteries are cells for hearing aid devices. In the past decades, considerable efforts have been done to develop secondary (rechargeable) zinc–air batteries for automobile and stationary energy storage applications. Though the commercialization of electrically rechargeable zinc–air batteries has not been achieved yet, substantial improvements have been made in enhancing the relatively low energy efficiency and extending the cycle life of air electrode. To solve some inconvenient of electrical charging such as long charging time and poor energy efficiency of bifunctional air electrode, mechanically and hydraulically rechargeable types and have been also widely explored. The principle, structure, and performance of some selected zinc–air batteries are herein described, together with some practical examples. The features and designs of their electrodes, electrolytes, and subsystems are also detailed.