Prussian blue analogues (PBAs) are considered promising cathode materials for sodium-ion batteries (SIBs). However, traditional PBAs have limitations, such as up to two-electron-transfer reactions, lattice vacancies, coordinated water, and poor intrinsic conductivity, leading to low capacity and poor rate performance. Herein, we have developed vacancy/water-free silver hexacyanoferrate nanoparticles interlinked with carbon nanotubes (AgHCF@CNTs) to improve the electrochemical performance. Benefiting from the four-electron redox capacity of Fe³⁺/Fe²⁺ and Ag⁺/Ag, the AgHCF@CNTs exhibit a reversible capacity of 168.4 mAh g^–1 at 50 mA g^–1, high rate capability (90.7 mAh g^–1 at 2 A g^–1), and long cycling stability over 500 cycles. The in-situ-generated Ag during the discharging/charging process, along with the large interstitial spaces of ferricyano-coordination groups, facilitate electron transfer and Na⁺ transportation, guaranteeing high electrochemical performance. This study provides insights into the design and synthesis strategy for advancing multiple-electron redox hexacyanoferrate as cathode materials for high-performance SIBs.

中文翻译：

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高性能钠离子电池普鲁士蓝模拟正极材料中的四电子氧化还原反应

普鲁士蓝类似物（PBA）被认为是有前途的钠离子电池（SIB）正极材料。然而，传统的PBA存在局限性，例如最多两个电子转移反应、晶格空位、配位水和较差的本征电导率，导致容量低和倍率性能差。在此，我们开发了与碳纳米管互连的空位/无水六氰基铁酸银纳米颗粒（AgHCF@CNTs）以提高电化学性能。受益于Fe ³⁺ /Fe ²⁺和Ag ⁺ /Ag的四电子氧化还原能力，AgHCF@CNT在50 mA g ^{–1下表现出168.4 mAh g –1}的可逆容量，高倍率能力（90.7 mAh g ^–1 at 2 A g ^–1 )，以及超过 500 个循环的长循环稳定性。放电/充电过程中原位生成的Ag以及铁氰基配位基团的大间隙空间有利于电子转移和Na ⁺传输，保证了高电化学性能。这项研究为推进多电子氧化还原六氰基铁酸盐作为高性能 SIB 的阴极材料的设计和合成策略提供了见解。