From Layers to Loops: Toward Sustainable Layered Oxide Cathodes and Circular Recycling Pathways for Sodium‐ and Lithium‐Ion Batteries

Cost-effective, high-capacity rechargeable stationary batteries are essential for supporting an integrated power grid that depends on sustainable energy sources. Sodium-ion batteries (SIBs) and lithium-ion batteries (LIBs) are both rechargeable energy storage technologies based on the reversible movement of ions between the anode and cathode during charge and discharge cycles. LIBs have dominated the market for decades because of their high energy density, long cycle life, and proven commercial viability; however, their complex recycling, high cost, and limited lithium availability raise concerns about their future use. On the other hand, SIBs are emerging as a promising alternative, especially for large-scale energy storage, due to the abundance of sodium in Earth's crust compared to lithium, making SIBs more sustainable and potentially more affordable. In this review, the benefits of SIBs are examined, and highlighted the important role of layered transition metal oxides (LTMOs) in achieving high-performance SIBs. Current challenges in utilizing LTMOs are discussed, and explored various strategies to enhance their electrochemical properties. Additionally, a comparative analysis of the recycling processes for LIBs and SIBs is presented to evaluate the sustainability of SIBs for long-term applications.