LAUSR

The prismatic and octahedral type layered cathode materials can provide enhanced performance in sodium‐ion batteries, due to low potential barrier during the intercalation. Among them, the prismatic layered Na‐Ni‐Mn‐O system is the most preferable electrode with a high theoretical capacity of 173 mAhg−1. The P2‐type phase could be attained only by satisfying the conditions of alkali, and transition metal ratio 0.5 ≤ x ≤ 1. The P2‐type layered structure in the Na‐Ni‐Mn‐O system has been studied via optimizing the alkali and transition metals in two phases. Here, the vacuum assisted solid‐state preparation method was carried out to avoid NiMnO4 impurities. From diffraction analysis and refinement data, the structural changes were analyzed, then the optimal ratio for perfect P2‐structure has been confirmed. The perfect P2‐structure was obtained only for the samples Na0.66Ni0.3Mn0.7O2, Na0.66Ni0.33Mn0.67O2. The prepared materials showed the initial discharge capacity of 194 mAhg−1 at 0.1C.