Zhou Yaozong, Jiang Ying, Zhang Yixin, Chen Yan, Wang Ziheng, Liu Anni, Lv Zekai, Xie Man
Beijing Key Laboratory of Environmental Science and Engineering, School of Material Science & Engineering, Beijing Institute of Technology, Beijing 100081, China.
ACS Appl Mater Interfaces. 2022 Jul 20;14(28):32149-32156. doi: 10.1021/acsami.2c08739. Epub 2022 Jul 6.
Prussian blue (PB) and its analogues are considered as promising cathode materials for sodium-ion batteries (SIBs) owing to their low cost and high capacity. However, it is still a huge challenge to avoid obvious capacity decay during cycling due to the structural collapse. Herein, we design a method to replace parts of Fe ion sites in PB with Ni ions to prepare fluffy-like nickel PB (PB-Ni) by cationic solution immersion, which improves cycling stability for sodium storage. The content of Ni in PB-Ni is explored by regulating the soaking time in the Ni-containing solution, which results in different effects on the electrochemical performance as cathodes of SIBs. Especially, PB-Ni-1d (soaking in NiCl solution for 1 day) exhibits an initial capacity of 114.2 mA h g at 50 mA g and a stable cycling performance of 800 cycles at 300 mA g. Furthermore, the reversible phase transformation and small volume variation for PB-Ni-1d are revealed by in situ X-ray diffraction characterization. The nickel hexacyanoferrate in outer layer maintains the cubic phase to stabilize the crystal structure. The cation-exchange strategy provides a facile idea to fabricate high-quality PB cathodes with superior stability for high-performance SIBs.
普鲁士蓝（PB）及其类似物因其低成本和高容量，被认为是钠离子电池（SIB）很有前景的正极材料。然而，由于结构坍塌，在循环过程中避免明显的容量衰减仍然是一个巨大的挑战。在此，我们设计了一种方法，通过阳离子溶液浸渍用镍离子取代PB中的部分铁离子位点，制备出蓬松状的镍普鲁士蓝（PB-Ni），从而提高了储钠的循环稳定性。通过调节在含镍溶液中的浸泡时间来探索PB-Ni中镍的含量，这对作为SIBs正极的电化学性能产生了不同的影响。特别是，PB-Ni-1d（在NiCl溶液中浸泡1天）在50 mA g下表现出114.2 mA h g的初始容量，在300 mA g下具有800次循环的稳定循环性能。此外，通过原位X射线衍射表征揭示了PB-Ni-1d的可逆相变和小体积变化。外层的镍铁氰化物保持立方相以稳定晶体结构。阳离子交换策略为制备具有优异稳定性的高质量PB正极以用于高性能SIBs提供了一个简便的思路。
