<br>P2/O3双相集成促进钠层状氧化物正极结构稳定性的增强,Chemical Engineering Journal

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P2/O3双相集成促进钠层状氧化物正极结构稳定性的增强
Chemical Engineering Journal ( IF 13.3 ) Pub Date : 2023-12-10 , DOI: 10.1016/j.cej.2023.147964
Chungang Lin , Peng Dai , Xiaolin Wang , Jingjing Sun , Shuxin Zhuang , Lina Wu , Mi Lu , Yanfen Wen

O3型钠层状氧化物由于其高理论容量而作为钠离子电池的极有前景的候选者而受到广泛关注。然而，他们经常遇到与复杂且不可逆的相变和缓慢动力学相关的挑战。为了克服这些问题，本文将O3型相与P2型相结合，系统地研究了O3型NaxLi0.05Mn0.55Ni0.3Cu0.075Mg0.025O2五元层状氧化物中不同比例的P2相对性能的影响。通过调节钠含量来提高电化学性能。 P2相比优化为32.3%的LMC3-P2/O3-32在0.2C倍率下表现出157.0 mAh g−1的高可逆容量，在10C下循环1000次后容量保持率为63.5%。当与硬碳阳极结合使用时，LCM3-P2/O3-32 在全电池中也表现出良好的循环寿命和倍率性能。原位X射线衍射分析证实，P2/O3双相阴极可以有效抑制纯O3阴极中发生的向贫Na O1相的有害相变和不可逆相变。较少的 Jahn-Teller 活性离子、增强的相变可逆性和改进的 Na+ 离子扩散动力学是 P2/O3 纳米级共生阴极改善的循环性能和倍率性能的原因。我们的工作揭示了通过层状氧化物阴极中的相集成来利用 P2 和 O3 相，这可以作为进一步开发先进钠离子电池高性能阴极材料的指南。

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P2/O3 biphase integration promoting the enhancement of structural stability for sodium layered oxide cathode

O3-type sodium layered oxides have garnered significant attention as highly promising candidates for sodium ion batteries due to their high theoretical capacity. However, they often encounter challenges associated with complex and irreversible phase transitions and sluggish kinetics. To overcome these issues, herein we integrate the O3-type phase with the P2-type phase and systematically investigate the influence of different ratios of P2 phase in O3-type NaxLi0.05Mn0.55Ni0.3Cu0.075Mg0.025O2 pentanary layered oxides on the electrochemical performance by tuning the sodium contents. The LMC3-P2/O3-32 with optimized P2 phase ratio of 32.3 % exhibits a high reversible capacity of 157.0 mAh g−1 at a rate of 0.2C and excellent capacity retention rate of 63.5 % after 1000 cycles at 10C. The LCM3-P2/O3-32 also demonstrates good cycle life and rate capability in full cells when coupled with a hard carbon anode. In situ X-ray diffraction analyses confirm that the detrimental phase transformations to Na-poor O1 phase and the irreversible phase transitions occurred in the pure O3 cathode can be effectively suppressed in the P2/O3 biphasic cathode. The less Jahn-Teller active ions, enhanced phase transition reversibility and improved diffusion kinetics of Na+ ions are responsible for the improved cyclability and rate capability in the P2/O3 nanoscale intergrowth cathode. Our work shed light on the leverage of P2 and O3 phases through phase integration in layered oxides cathodes, which can serve as a guideline for the further development of high-performance cathode materials for advanced sodium ion batteries.

更新日期：2023-12-10

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