Key Takeaways & Executive Findings
- •• Overview of metal–air batteries architecture, reaction mechanisms, and challenges in developing bifunctional air-breathing electrodes. • Comprehensive discussion on engineering the microenvironment chemistry of noble metal-free bifunctional oxygen electrocatalysts. • Insights into future research directions for earth-abundant bifunctional catalysts with enhanced performance and durability. • Emphasis on synthesis strategies, microenvironmental modulations, and stabilized systems for efficient zinc– and lithium–air batteries.
Abstract
Rechargeable metal–air batteries have gained significant interest due to their high energy density and environmental benignity. However, these batteries face significant challenges, particularly related to the air-breathing electrode, resulting in poor cycle life, low efficiency, and catalyst degradation. Developing a robust bifunctional electrocatalyst remains difficult, as oxygen electrocatalysis involves sluggish kinetics and follows different reaction pathways, often requiring distinct active sites. Consequently, the poorly understood mechanisms and irreversible surface reconstruction in the catalyst’s microenvironment, such as atomic modulation, nano-/microscale, and surface interfaces, lead to accelerated degradation during charge and discharge cycles. Overcoming these barriers requires advancements in the development and understanding of bifunctional electrocatalysts. In this review, the critical components of metal–air batteries, the associated challenges, and the current engineering approaches to address these issues are discussed. Additionally, the mechanisms of oxygen electrocatalysis on the air electrodes are examined, along with insights into how chemical characteristics of materials influence these mechanisms. Furthermore, recent advances in bifunctional electrocatalysts are highlighted, with an emphasis on the synthesis strategies, microenvironmental modulations, and stabilized systems demonstrating efficient performance, particularly zinc– and lithium–air batteries. Finally, perspectives and future research directions are provided for designing efficient and durable bifunctional electrocatalysts for metal–air batteries.
1. Introduction
The increasing global energy demand and the urgency for transition to a decarbonized economy have paved new trends in electrochemical energy storage and conversion devices, including supercapacitors, fuel cells, water electrolyzers, and batteries, to play a key role toward a green, clean, and sustainable energy economy. These clean electrochemical energy technologies can make a bridge between the demand and supply of electricity produced from intermittent renewable energy sources and thus be used in many economic sectors like communication and transportation [1].
The primary pillar for electrochemical energy storage is the battery, which allows the storage of chemical energy and can be used, when necessary, in stationary stations or portable devices, making the battery a very pivotal device in daily needs. Although there has been significant progress in battery development, such as Li–ion batteries (LIBs) powering the electric vehicles (EVs), there is a big challenge to address due to the increasing demand for these devices. The raw materials resources’ long-term availability and geographical distribution of crucial metal elements for LIBs, which rely on scarce and finite resources such as cobalt and lithium, are limiting factors for future utilization of LIBs [2]. Additionally, safety concerns such as uncontrollable flammability in the case of using LIBs at a mass scale, recycling or disposal of materials after LIBs end-of-life pose a significant challenge to satisfy the needs of environmental-friendly technologies and ever-increasing energy storage [3]. To get a socioeconomic credence for the battery technology, we need to showcase high power and energy density coupled with cost-effectiveness. For this, rechargeable metal–air batteries (MABs) are used in a wide range of applications due to their low cost compared to LIBs. The MABs al...
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Jean Marie Vianney Nsanzimana, Lebin Cai, Zhongqing Jiang, Bao Yu Xia, Thandavarayan Maiyalagan (2025). Engineering Bifunctional Catalytic Microenvironments for Durable and High-Energy-Density Metal–Air Batteries. Nano-Micro Letters. https://doi.org/10.1007/s40820-025-01799-w
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Frequently Asked Questions
What are metal–air batteries and why are they important?
Metal–air batteries are electrochemical energy storage devices that use a metal anode and an air-breathing cathode, offering high energy density and environmental benignity. They are considered promising alternatives to lithium-ion batteries due to their low cost and high theoretical energy density, especially for applications like electric vehicles and grid storage.
What are the main challenges in developing bifunctional electrocatalysts for metal–air batteries?
The main challenges include sluggish kinetics of oxygen reduction and evolution reactions, the need for distinct active sites for each reaction, and degradation of catalysts due to irreversible surface reconstruction in the microenvironment. These issues lead to poor cycle life and low efficiency.
How can engineering the catalytic microenvironment improve battery performance?
Engineering the microenvironment involves atomic modulation, nano-/microscale structuring, and surface interface control. These strategies can enhance the activity, stability, and durability of bifunctional catalysts, thereby improving the overall performance and lifespan of metal–air batteries.
What are the future research directions for bifunctional catalysts in metal–air batteries?
Future research should focus on developing earth-abundant, noble metal-free catalysts with enhanced performance and durability. This includes exploring new synthesis strategies, understanding reaction mechanisms, and optimizing the microenvironment to achieve scalable and cost-effective applications.
Which types of metal–air batteries are highlighted in this review?
The review particularly highlights zinc–air and lithium–air batteries, as they are among the most promising metal–air battery systems due to their high energy density and potential for practical applications.
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