Prussian blue analogues, particularly metal hexacyanoferrates with double octahedral coordination (DOC) structures, hold great promise as cathode materials for sodium-ion batteries. However, their practical application is hindered by limited structural stability and restricted ionic diffusion channels inherent to the DOC structure. In this study, we have successfully integrated a mixed tetrahedral and octahedral coordination (TOC) structure with the DOC structure by a dual polymerization and high-entropy strategy, thereby optimizing the central metal coordination environment in hexacyanoferrate cathodes. It leverages the TOC structure's superiorities in structural stability and ionic diffusion, resulting in a hexacyanoferrate-based cathode that exhibits exceptional performance, with a capacity retention of 81.6% after 1000 cycles at 0.5 A g-1 and high rate capabilities of 96.7 and 89.1 mAh g-1 at 0.5 and 1 A g-1, respectively. These findings not only underscore the potential of the TOC design for prussian blue cathodes but also pave the way for the development of high-performance, durable sodium-ion battery systems.

中文翻译：

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中心金属配位环境优化增强了普鲁士蓝类似物中 Na 的扩散和结构稳定性


普鲁士蓝类似物，特别是具有双八面体配位 （DOC） 结构的金属六氰基铁酸盐，作为钠离子电池的正极材料具有很大的前景。然而，它们的实际应用受到 DOC 结构固有的有限结构稳定性和受限的离子扩散通道的阻碍。在本研究中，我们通过双重聚合和高熵策略成功地将混合四面体和八面体配位 （TOC） 结构与 DOC 结构集成在一起，从而优化了六氰基铁酸盐阴极中的中心金属配位环境。它利用 TOC 结构在结构稳定性和离子扩散方面的优势，产生了具有卓越性能的六氰基铁酸盐阴极，在 0.5 A g-1 下循环 1000 次后容量保持率为 81.6%，在 0.5 和 1 A g-1 下分别具有 96.7 和 89.1 mAh g-1 的高倍率能力。这些发现不仅强调了普鲁士蓝阴极 TOC 设计的潜力，还为高性能、耐用的钠离子电池系统的开发铺平了道路。