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Tailoring alternating heteroepitaxial nanostructures in Na-ion layered oxide cathodes via an in-situ composition modulation route
Nano Energy ( IF 16.8 ) Pub Date : 2017-12-14 , DOI: 10.1016/j.nanoen.2017.12.014
Qun Huang , Jiatu Liu , Li Zhang , Sheng Xu , Libao Chen , Peng Wang , Douglas G. Ivey , Weifeng Wei

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.



中文翻译:

通过原位组成调制途径在Na离子层状氧化物阴极中定制交替的异质外延纳米结构

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。

更新日期:2017-12-14
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