State-of-the-Art Carbon Cathodes with Their Intercalation Chemistry, Performance, and Challenges for Aluminum-Ion Batteries

Aluminum-ion batteries (AIBs) offer several advantages over lithium-ion batteries including safety, higher energy density, rapid charging, reduced environmental impact, and scalability. In the case of anodes, interest in electropositive metals for rechargeable batteries, particularly aluminum, has surged due to their abundance (8.23 wt % in earth’s crust) and high volumetric capacity (8050 mAh g –1 ). Concerning cathodes, various materials are explored for AIBs, including transition metal oxides (e.g., V 2 O 5, MoO 2 ), sulfides (e.g., SeS, CuS, and MoS), carbon, and conductive polymers. Among these, carbon remains the ideal choice due to its work function compatibility with aluminum, stability, high conductivity, anion intercalation capability, and scalability, despite the low intercalation capacity of graphite and its limiting energy density and limiting energy density. In this review, we elaborate the current progress and challenges in utilizing different carbon materials for aluminum and chloride ion intercalation realized since 2015, focusing on graphite, carbon composites, carbon nanotubes (CNTs), and other nanostructured carbons. We analyzed the trade-offs and challenges in optimizing these electrodes, including balancing energy density, cycling stability, addressing structural degradation, and managing electrode swelling. The focus of this review was placed on the strategies to overcome these hurdles, such as the utilization of nanoscale composites, conductive additives, and development of hierarchical architectures, along with recent advancements in their synthesis methods, different electrode morphology, and functional coatings to enhance the stability of carbon. Investigation into high-energy cathodes leveraging triple-ion intercalation chemistry (Al 3+ ion) holds promise for advancing sustainable battery technology.