The major hurdle of room temperature sodium-ion batteries (NIBs) for large-scale energy storage applications lies in developing new electrode materials with higher energy/power densities and improved durability. This work presents a novel Na-P3/Li₂MnO₃ layered composite cathode with an alternating heteroepitaxial nanostructure fabricated by an in-situ composition modulation route. XRD structural refinement, synchrotron XAS and aberration-corrected HAADF-/ABF-STEM were employed to understand the structure evolution accompanying Li substitution. It is revealed that the in-situ formation of Li₂MnO₃ (Li-O’3) changes the crystallographic and chemical features of the neighboring Na-P3 layered matrix significantly and leads to the alternating Na-P3/Li-O’3 heteroepitaxial nanostructure. This alternating heteroepitaxial nanostructure delivers an extremely high reversible capacity of ~ 210 mAh g⁻¹ between 1.5 and 4.5 V vs. Na/Na⁺, much improved cycling stability and excellent electrode kinetics. Its enhanced electrochemical performance can be ascribed to the effective suppression of the P3-P3’’ phase transition and subsequent amorphization upon cycling to 4.5 V.

对于大规模储能应用而言，室温钠离子电池（NIB）的主要障碍在于开发具有更高能量/功率密度和更高耐用性的新型电极材料。这项工作提出了一种新颖的Na-P3 / Li ₂ MnO ₃层状复合阴极，该阴极具有通过原位组成调制途径制造的交替异质外延纳米结构。利用XRD的结构改进，同步加速器XAS和像差校正的HAADF- / ABF-STEM来了解伴随Li取代的结构演变。揭示了Li ₂ MnO _3的原位形成（Li-O'3）会显着改变相邻的Na-P3层状基质的晶体学和化学特征，并导致交替的Na-P3 / Li-O'3异质外延纳米结构。与Na / Na ^+相比，这种交替的异质外延纳米结构在1.5至4.5 V之间具有极高的可逆容量〜210 mAh g ^-1，大大提高了循环稳定性，并具有出色的电极动力学。其增强的电化学性能可归因于有效抑制P3-P3''相变以及随后在循环至4.5 V时非晶化。