Co‐ and Ni‐Free O3‐Type Layered NaFe0.45Mn0.5Ti0.05O2 Cathode for Sodium‐Ion Batteries

NaFe_0.45Mn_0.50Ti_0.05O₂ is introduced as a sustainable, cobalt- and nickel-free sodium-ion cathode. The Ti⁴⁺ doping enhances cycling stability and structural robustness. Excellent full-cell compatibility and extended pouch cell cycling confirm the practical viability of this low-cost cathode for sodium-ion batteries.

The rising costs of cobalt and nickel, alongside mounting environmental concerns, have spurred intensive research into alternative battery chemistries that eliminate these critical elements. This shift aligns with the broader industry push toward low-cost, sustainable materials that can rival the performance of lithiumironphosphate (LFP) systems. In this context, the present work introduces a layered oxide cathode composition, NaFe_0.45Mn_0.5Ti_0.05O₂ (NFMTO), which delivers high specific capacity and enhanced cycling stability. The substitution of Ti⁴⁺ into the Fe/Mn lattice effectively modifies the transition metal–oxygen (TM-O) layer spacing, thereby improving structural stability during cycling. As a result, the NFMTO cathode exhibits an initial discharge capacity of 125 mAh g⁻¹ at 0.1C (2.0–4.2 V vs. Na⁺/Na) and retains 78.4% of its capacity after 50 cycles. Additionally, it delivers 118 mAh g⁻¹ with 70% capacity retention over 200 cycles in a voltage window of 2.0–4.0 V. The full-cell performance of NFMTO is evaluated in a pouch cell configuration using hard carbon as the anode, further demonstrating its practical viability. The assembled pouch cell delivered an initial discharge capacity of 103 mAh g⁻¹ at 0.05C (2.0–4.2 V) and retained 90% of its capacity after 10 cycles.

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