Abstract：
Prussian blue analogs (PBAs) have been widely recognized as superior cathode materials for sodium-ion batteries (SIBs) owing to numerous merits. However, originating from the rapid crystal growth, PBAs still suffer from considerable vacancy defects and interstitial water, making the preparation of long-cycle-life PBAs the greatest challenge for its practical application. Herein, a novel equilibrium chelation strategy is first proposed to synthesize a high crystallinity (94.7%) PBAs, which is realized by modulating the chelating potency of strong chelating agents via \"acid effect\" to achieve a moderate chelating effect, forcefully breaking through the bottleneck of poor cyclic stability for PBAs cathodes. Impressively, the as-prepared highly crystalline PBAs represent an unprecedented level of electrochemical performance including ultra-long lifespan (10000 cycles with 86.32% capacity maintenance at 6 A g-1), excellent rate capability (82.0 mAh g-1 at 6 A g-1). Meanwhile, by pairing with commercial hard carbon, the as-prepared PBAs-based SIBs exhibit high energy density (350 Wh kg-1) and excellent capacity retention (82.4% after 1500 cycles), highlighting its promising potential for large-scale energy storage applications.
摘要：
由于许多优点，普鲁士蓝类似物（PBA）已被广泛认为是钠离子电池（SIB）的优质阴极材料。然而,源于快速的晶体生长，PBA仍然存在相当大的空位缺陷和间隙水，使长周期寿命PBA的制备成为其实际应用的最大挑战。在这里，首先提出了一种新的平衡螯合策略来合成高结晶度(94.7%)的PBA，这是通过“酸效应”调节强螯合剂的螯合效力来实现的，以实现适度的螯合效果，有力地突破了PBAs阴极循环稳定性差的瓶颈。令人印象深刻的是,制备的高度结晶的PBA代表了前所未有的电化学性能水平，包括超长的寿命（10000次循环，在6Ag-1时保持86.32％的容量），优异的倍率性能(82.0mAhg-1在6Ag-1)。同时,通过与商业硬碳配对，所制备的基于PBA的SIB具有高能量密度（350Whkg-1）和出色的容量保留率（1500次循环后为82.4％），突出了其在大规模储能应用中的潜力。
