Relating Catalysis between Fuel Cell and Metal-Air Batteries

• Published in: Matter Vol. 2; no. 1; pp. 32 - 49
• Main Authors: Li, Matthew, Bi, Xuanxuan, Wang, Rongyue, Li, Yingbo, Jiang, Gaopeng, Li, Liang, Zhong, Cheng, Chen, Zhongwei, Lu, Jun
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 08.01.2020; Elsevier
• Subjects: fuel cell; Li-O2 battery; oxygen evolution reaction; oxygen reduction reaction; Zn-air battery; oxygen evolution reaction; Zn-air battery; fuel cell; oxygen reduction reaction; Li-O2 battery
• ISSN: 2590-2385; 2590-2385
• DOI: 10.1016/j.matt.2019.10.007

With the ever-increasing demand for higher-performing energy-storage systems, electrocatalysis has become a major topic of interest in an attempt to enhance the electrochemical performance of many electrochemical technologies. Discoveries pertaining to the oxygen reduction reaction catalyst helped enable the commercialization of fuel-cell-based electric vehicles. However, a closely related technology, the metal-air battery, has yet to find commercial application. Much like the Li-ion battery, metal-air batteries can potentially utilize the electrical grid network for charging, bypassing the need for establishing a hydrogen infrastructure. Among the metal-air batteries, Li-air and Zn-air batteries have drawn much interest in the past decade. Unfortunately, state-of-the art metal-air batteries still produce performances that are well below practical levels. In this brief perspective, we hope to bridge some of the ideas from fuel cell to that of metal-air batteries with the aim of inspiring new ideas and directions for future research. [Display omitted] Catalyst research for fuel cells has led to much advancement in humanity's understanding of the underlying physics of the process, significantly enhancing the performance of the technologies. In contrast, metal-air batteries such as Li-air and Zn-air batteries remain to be solved. Although the metal anode used in this these systems does play a large role in limiting their commercial success, catalysis also remains quite challenging. In this perspective, a discussion is provided on the similarities and differences between metal-air catalysts and fuel cells for aqueous (alkaline/acidic) and aprotic electrolytes. By attempting to bridge the discussion between the fields and providing our own opinion on the subject, we hope that this perspective will present itself as a starting point in emulating the success of catalysis in fuel cells in the metal-air systems. Metal-air and fuel cells are both highly attractive energy options for electric vehicles. However, differences among their catalyst design have diverged the two fields with particular separation between aprotic Li-air and aqueous fuel cells. This perspective clarifies the specific differences between the different types of catalyst (aqueous alkaline/acidic and aprotic electrolytes) and attempts to draw analogies for the reader in hopes of sparking new research ideas.