Low‐Cost Layered Cathodes Toward Practical Sodium‐Ion Batteries: Scientific Challenges, Resolution Strategies, and Economic Efficiency

ABSTRACT Lithium‐ion batteries (LIBs) are the most widely used commercial rechargeable batteries, but the stable supply of key raw materials such as lithium, nickel, and cobalt faces challenges. Sodium‐ion batteries (SIBs) are considered as potential alternatives and complements to LIBs due to similar working principles and the abundance of sodium resources. Layered oxide cathode materials (LOCMs) are recognized as one of the most promising practical cathodes for SIBs because of mature synthesis technology and satisfactory energy density. However, the use of nickel in LOCMs for SIBs has raised concerns about environmental pollution during nickel production and the risk of price volatility stemming from the widespread application of high‐nickel LOCMs for LIBs. Therefore, developing low‐cost nickel‐free LOCMs is crucial for enhancing the environmental friendliness and cost advantages of SIBs. For low‐cost LOCMs, this review discusses the feasibility of replacing Ni 2+ /Ni 4+ with Fe 3+ /Fe 4+ and Mn 3+ /Mn 4+ for charge compensation in SIBs, and summarizes the resulting critical scientific challenges (Fe migration, Mn dissolution, Jahn‐Teller effect, Na deficiency, and thermal instability). Economic efficiency assessment based on cost and electrochemical properties indicates that low‐cost LOCMs exhibit the highest cost‐performance ratio. Finally, to accelerate the commercialization of cost‐effective SIBs technologies, this review outlines promising development pathways of low‐cost LOCMs.