As a group of attractive photoelectromagnetic and catalytic functional materials, metal oxychlorides have been attracting attention for electrochemical energy storage in rechargeable chloride ion battery (CIB) systems recently. Their application, however, is limited by the complicated synthesis and/or poor cycling stability. Herein, a facile strategy using vacuum impregnation and subsequent thermal decomposition at mild conditions has been developed to synthesize the FeOCl/CMK-3 nanocomposite material. Benefiting from the nanoconfined structure, a high-performance FeOCl/CMK-3 cathode, which has a high discharge capacity of 202 mAh g^–1, superior cycling stability, and significantly improved charge transfer and chloride ion diffusion, is achieved. The electrolyte component is found to show a high affinity with the chlorine layer in the FeOCl phase, inducing evident expansion of the FeOCl layers along the b-axis direction and thus boosting a new potential liquid exfoliation approach for preparing 2D FeOCl material. Importantly, reversible electrochemical reactions of the FeOCl cathode material based on the redox reactions of iron species and chloride ion transfer are revealed.

中文翻译：

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纳米约束氧化铁材料作为可充电氯化物离子电池的高性能阴极

作为一组有吸引力的光电磁和催化功能材料，金属氧氯化物最近在可充电氯离子电池（CIB）系统中的电化学能量存储中引起了人们的注意。然而，它们的应用受到复杂的合成和/或较差的循环稳定性的限制。在本文中，已经开发了使用真空浸渍和随后在温和条件下进行热分解的简便策略来合成FeOCl / CMK-3纳米复合材料。得益于纳米约束结构，高性能的FeOCl / CMK-3阴极具有202 mAh g ^–1的高放电容量实现了优异的循环稳定性，并显着改善了电荷转移和氯离子扩散。发现电解质组分在FeOCl相中与氯层显示出高亲合力，引起FeOCl层沿b轴方向的明显膨胀，因此促进了制备2D FeOCl材料的新的潜在的液体剥离方法。重要地，揭示了基于铁物种的氧化还原反应和氯离子转移的FeOCl阴极材料的可逆电化学反应。