A Mechanistic Overview of the Current Status and Future Challenges in Air Cathode for Aluminum Air Batteries

Abstract

Aluminum air batteries (AABs) are a desirable option for portable electronic devices and electric vehicles (EVs) due to their high theoretical energy density (8100 Wh K−1), low cost, and high safety compared to state‐of‐the‐art lithium‐ion batteries (LIBs). However, numerous unresolved technological and scientific issues are preventing AABs from expanding further. One of the key issues is the catalytic reaction kinetics of the air cathode as the fuel (oxygen) for AAB is reduced there. Additionally, the performance and price of an AAB are directly influenced by an air electrode integrated with an oxygen electrocatalyst, which is thought to be the most crucial element. In this study, we covered the oxygen chemistry of the air cathode as well as a brief discussion of the mechanistic insights of active catalysts and how they catalyze and enhance oxygen chemistry reactions. There is also extensive discussion of research into electrocatalytic materials that outperform Pt/C such as nonprecious metal catalysts, metal oxide, perovskites, metal‐organic framework, carbonaceous materials, and their composites. Finally, we provide an overview of the present state, and possible future direction for air cathodes in AABs.

Aluminum–air batteries: current advances and promises with future directions

“…The reaction overpotential η can be expressed as eqn (34) using the Butler–Volmer equation. 57 where the symbol R represents the ideal gas constant, T denotes the temperature, α signifies the transfer coefficient, and J represents the current exchange density. The equation is expressed concisely as eqn (35) .…”

“…Also, the particle shape and exposed surface are critical in determining the catalyst performance. 57 A positive correlation exists between the response rate and the extent of exposure to the catalyst surface. For the feasibility of an Al–air battery, the air cathode must incorporate an appropriate electrocatalyst to modify its ORR activity.…”

“…55,56 Additionally, Al–air batteries have the potential to be more environmentally friendly, given that aluminum is readily recyclable and poses fewer environmental concerns compared to other metals. 57,58…”

Recent Developments on Electroactive Organic Electrolytes for Non‐Aqueous Redox Flow Batteries: Current Status, Challenges, and Prospects

“…NARFBs represent an emerging class of energy storage technologies that offer several advantages compared to already developed technologies, such as aqueous redox flow batteries (ARFBs), lithium-ion batteries (LIBs), supercapacitors (SCs), hybrid supercapacitors (HSCs), and other conventional methods. [20][21][22][23][24] NARFB technology has several advantages such as high efficiency, high energy density, long cycle life, fast response times, safety, and scalability. Moreover, NARFBs can utilize a variety of redox couples to make it a cost-effective and viable storage option.…”

“…Another new family of cobalt(II) complexes was synthesized by substituting the terminal pyridyl groups of 2,2':6',2"terpyridine with azole-pyridine type ligands (23). These complexes were tested as redox species in novel NARFBs.…”