P2-NaCo0.5Mn0.5O2 as a Positive Electrode Material for Sodium- Ion Batteries

As a promising positive electrode material for sodium-ion batteries (SIBs), layered sodium oxides have attracted considerable attention in recent years. In this work, stoichiometric P2-phase NaCo0.5Mn0.5O2 was prepared through the conventional solidstate reaction, and its structural and physical properties were studied in terms of XRD, XPS, and magnetic susceptibility. Furthermore, the P2-NaCo0.5Mn0.5O2 electrode delivered a discharge capacity of 124.3 mAhg(-1) and almost 100% initial coulombic efficiency over the potential window of 1.5-4.15 V. It also showed good cycle stability, with a reversible capacity and capacity retention reaching approximately 85 mAhg(-1) and 99%, respectively, at the 5C rate after 100 cycles. Additionally, cyclic voltammetry and ex situ XRD were employed to explain the electrochemical behavior at the different electrochemical stages. Owing to the applicable performances, P2-NaCo0.5Mn0.5O2 can be considered as a potential positive electrode material for SIBs.