The sodium manganese hexacyanoferrate (MnPB) has drawn widely attention as a remarkable cathode material for sodium-ions batteries owing to its high theoretical capacity (∼170 mAh g), environmental-friendly and low cost. However, it suffers from serious capacity fading and inferior cycling stability caused by the inevitable Jahn-Teller distortion and significant volume change during Nainsertion/extraction process. Herein, we propose a simple one-pot method for constructing a multi-shelled Mn-based Prussian blue through sequentially epitaxial growth CoPB and NiPB on the surface of MnPB (NiCoMnPB). The density functional theory calculations demonstrate the unequal affinities of different metal ions with various chelating agents (citrate and ferrocyanide), leading to the dissociation and recombination of metal ions and chelating agents in a certain order. Effectively inheriting merits of CoPB and NiPB, the NiCoMnPB reveals enhanced charge transfer kinetics, suppressed volume change and alleviative Jahn-Teller distortion during cycling, thereby exhibiting superior rate capacity (∼54.2 mAh g at 3200 mA/g), long-term cyclic stability and capacity retention (∼76 % over 1000 cycles at 800 mA/g). This work provides a simple method to construct multi-shelled PBAs, which can integrate the virtues of different materials to ameliorate the electrochemical properties of initial materials.

中文翻译：

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用于高稳定性钠离子电池的顺序外延多壳锰基普鲁士蓝阴极

六氰基铁酸锰钠（MnPB）由于其理论容量高（~170 mAh g）、环境友好且成本低廉，作为一种卓越的钠离子电池正极材料而受到广泛关注。然而，由于不可避免的Jahn-Teller变形和插入/提取过程中显着的体积变化，导致其容量衰减严重，循环稳定性差。在此，我们提出了一种简单的一锅法，通过在 MnPB (NiCoMnPB) 表面顺序外延生长 CoPB 和 NiPB 来构建多壳锰基普鲁士蓝。密度泛函理论计算表明，不同金属离子与各种螯合剂（柠檬酸盐和亚铁氰化物）的亲和力不相等，导致金属离子和螯合剂按一定顺序解离和重组。 NiCoMnPB有效继承了CoPB和NiPB的优点，在循环过程中表现出增强的电荷转移动力学、抑制的体积变化和减轻的Jahn-Teller变形，从而表现出优异的倍率容量（3200 mA/g时~54.2 mAh g）和长期循环稳定性和容量保持率（800 mA/g 下 1000 次循环后约 76%）。这项工作提供了一种构建多壳PBA的简单方法，可以整合不同材料的优点，改善初始材料的电化学性能。