Layered transition metal oxides are considered to be promising candidates as cathode materials for sodium-ion batteries. Herein, a facile solid-state reaction is developed to synthesize hexagons plate-like Na_0.67Ni_0.25Mn_0.75O_2+δ (denoted as P2-NNM) material with habit plane formed. The structure of this layered oxide is characterized by XRD, HR-TEM and SAED. The layered material delivers a high reversible capacity of 91.8 mAh g⁻¹ at 0.2 C with a capacity retention of 94.4 % after 280 cycles, superior rate capability and long cycle life (84.2 % capacity retention after 1000 cycle). Ni²⁺ is an active ion and Ni doping alleviates the Jahn-Teller distortion, and Mn³⁺/Mn⁴⁺ coexist as Mn⁴⁺ is desired from the stability perspective. Particularly, CV and XPS results confirm these results. Moreover, the electrode exhibits a quasi-solid-solution reaction during the sodium extraction and insertion. This contribution demonstrates that P2-NNM is a promising cathode electrode for rechargeable long-life sodium-ion batteries.

层状过渡金属氧化物被认为是钠离子电池正极材料的有前途的候选材料。在此，进行了容易的固相反应，以合成形成有惯性面的六方晶状的板状的Na _0.67 Ni _0.25 Mn _0.75 O _{2 +δ}（表示为P2-NNM）。该层状氧化物的结构由XRD，HR-TEM和SAED表征。层状材料在0.2 C下可提供91.8 mAh g ^-1的高可逆容量，在280次循环后的容量保持率为94.4％，优异的倍率容量和长循环寿命（1000次循环后的容量保持率为84.2％）。Ni ²⁺是活性离子，Ni掺杂可减轻Jahn-Teller变形，而Mn ³⁺从稳定性的观点来看，/ Mn ⁴⁺共存为Mn ⁴⁺是理想的。特别是，CV和XPS结果证实了这些结果。此外，在钠提取和插入期间，电极表现出准固溶反应。这一贡献证明P2-NNM是用于可充电长寿命钠离子电池的有希望的阴极。