Degradation characteristics of air cathode in zinc air fuel cells

Recent Advances in Materials and Design of Electrochemically Rechargeable Zinc–Air Batteries

“…The charging potential of 2 V or above is often required. Thus, the energy efficiency of most of the current rechargeable Zn–air batteries is less than 60%, which can be attributed to several issues . First, the bifunctional O 2 electrocatalysts on air electrodes are not active enough to effectively drive the sluggish ORR and OER during the discharging and charging events.…”

“…To improve the performance of Zn electrodes, many groups have also explored various additives to influence the solubility and mass transfer of Zn species in electrolytes. Early studies have used some inorganic salts, such as KF, As 3 O 4 , K 2 HBO 3 , K 3 BO 3 , K 2 CO 3 , and K 2 CrO 4 , to create low Zn solubility electrolytes . The rate of Zn electrode shape change was significantly reduced compared to those in electrolytes without inorganic salts .…”

“…Meanwhile, CO 2 can react with KOH to form K 2 CO 3 or KHCO 3 , which may block the channels in the gas diffusion layer of air electrodes and reduce the electrical conductive of electrolytes. Adsorbents can be used to remove CO 2 by chemisorption, resulting in additional operation cost, and space requirement for hosting adsorbents in Zn–air batteries.…”

“…Third, they can suppress Zn self‐corrosion and Zn dendrite formation, which can help further extend battery cycle life . Several aprotic ionic liquids, such as 1‐butyl‐1‐methylpyrrolidinium bis(trifluoromethanesulfonyl)imide, 1‐ethyl‐3‐methylimidazolium bis(trifluoromethanesulfonyl)imide, 1‐butyl‐1‐methylpyrrolidinium dicyanamide, and 1‐ethyl‐3‐methylimidazolium dicyanamide, have been studies as electrolytes for Zn electrodes . Dendrite free Zn deposition can be achieved because of the selective coordination between ionic liquid anions and Zn cations .…”

“…In the last few years, several review articles have provided excellent introductions on the geometric structure and charge storage mechanisms of Zn–air batteries as well as the efforts devoted to improving various battery components . Nevertheless, the research interest over Zn–air batteries is progressing very rapidly as evident by the increase in number of scientific publications from “78” (till the end of 2010) to “316” as of May 2018 (based on a simple search made on the Web of Science using “Zinc–air battery” (in quotation marks) as the keywords).…”