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Boosting fast ionic transport and stability of O3-NaNi1/3Fe1/3Mn1/3O2 cathode via Al/Cu synergistically modulating microstructure for high-rate sodium-ion batteries
Chemical Engineering Journal ( IF 13.3 ) Pub Date : 2023-09-16 , DOI: 10.1016/j.cej.2023.146090
Sheng Feng , Chujun Zheng , Zhiyang Song , Xiangwei Wu , Meifen Wu , Fangfang Xu , Zhaoyin Wen

As one of the most promising sodium-ion cathodes, O3-type transition metal layered oxides (NaxTMO2) with high specific capacity and low cost have received intensive attention. However, they still face the issues of slow Na+ transfer kinetics and undesirable phase transitions. In this study, we report a novel Al and Cu dual substitution strategy to prepare a NaNi1/3Fe1/3Mn1/3O2 cathode using a spray drying method. Specifically, Al serves to stabilize the TM-O layer structure, mitigating adverse phase transitions, while Cu contributes additional capacity and enhances air stability. Consequently, the NaNi0.32Fe0.32Mn0.32Al0.02Cu0.02O2 cathode exhibits enlarged Na+ transfer channels, modulated particle morphology and strengthened layer framework. With the enhanced structure, the John-Teller distortion, adverse phase transitions of O'3 and OP2, and intragranular fatigue cracks are effectively suppressed, leading to improved cycle and air stability. The NaNi0.32Fe0.32Mn0.32Al0.02Cu0.02O2 cathode can maintain 81% of its initial specific capacity at 1C rate after 200 cycles and can obtain a specific capacity of 113 mAh/g even at 5C rate. Furthermore, we find that strengthened Na+ transport kinetics promote homogenous Na+ distribution, which can reduce the formation of unstable interphases to achieve more reversible phase transition. This work helps to better unveil the relationship between Na+ transfer kinetics and phase transition, provides new insight for designing high-performance sodium-ion cathodes.



中文翻译:

通过Al/Cu协同调节高倍率钠离子电池的微观结构提高O3-NaNi1/3Fe1/3Mn1/3O2阴极的快速离子传输和稳定性

作为最有前途的钠离子正极之一,O3型过渡金属层状氧化物(Na x TMO 2)以其高比容量和低成本而受到广泛关注。然而,它们仍然面临Na +转移动力学缓慢和不良相变的问题。在这项研究中,我们报告了一种新颖的Al和Cu双重取代策略,使用喷雾干燥方法制备NaNi 1/3 Fe 1/3 Mn 1/3 O 2阴极。具体来说,Al 可以稳定 TM-O 层结构,减轻不利的相变,而 Cu 则有助于增加容量并增强空气稳定性。因此,NaNi 0.32 Fe 0.32Mn 0.32 Al 0.02 Cu 0.02 O 2阴极表现出扩大的Na +传输通道、调制的颗粒形态和强化的层结构。通过增强的结构,约翰-泰勒变形、O'3和OP2的不利相变以及晶内疲劳裂纹得到有效抑制,从而改善循环和空气稳定性。NaNi 0.32 Fe 0.32 Mn 0.32 Al 0.02 Cu 0.02 O 2正极在1C倍率下循环200次后仍能保持初始比容量的81%,即使在5C倍率下也能获得113mAh/g的比容量。此外,我们发现加强的Na +传输动力学促进均匀的Na +分布,这可以减少不稳定界面的形成,从而实现更可逆的相变。这项工作有助于更好地揭示Na +转移动力学与相变之间的关系,为设计高性能钠离子阴极提供新的见解。

更新日期:2023-09-16
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