Given their structural merits and electrochemical benefits, Prussian blue analogues (PBAs) hold great promise as cathode materials for potassium ion batteries (PIBs). However, these cathodes face formidable hurdles by structural failure and poor rate capability, primarily resulting from significant volumetric changes and sluggish kinetics during repeated intercalation/deintercalation of bulky K+ ions. Theoretically, the study reveals explicitly that quaternary medium‐entropy PBAs (Q‐ME‐PBAs), composed of Fe, Ni, Co, and Cu, demonstrate minimal lattice volume variations and low diffusion barriers during K+ ion interactions. This endows Q‐ME‐PBA with favorable ability to induce significant 3D lattice distortion, enabling the material to endure structural alterations during K+ ion movements and reinforce phase stability. Consequently, leveraging the structural and compositional advantages, the resultant Q‐ME‐PBAs cathode showcases exceptional cycling performance, maintaining over 90% capacity retention after 300 cycles at 0.25 C with a high initial coulombic efficiency of 94.4% and retaining 74.7% capacity even after an ultra‐long 10 000 cycles at 3.75 C over 147 days. Notably, full cells paired with hard carbon and graphite anodes show outstanding cycling stability and rate capability. This study charts fresh design directions for crafting high‐performance and durable cathodes through medium‐entropy lattice engineering for advanced PIBs.

中文翻译：

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在普鲁士蓝类似物阴极上采用中等熵晶格工程实现的长效耐用的钾离子电池


鉴于其结构优点和电化学优势，普鲁士蓝类似物 （PBA） 作为钾离子电池 （PIB） 的正极材料大有可为。然而，这些阴极面临着结构故障和低倍率能力的巨大障碍，这主要是由于大体积 K+ 离子反复插层/脱嵌过程中显着的体积变化和动力学缓慢造成的。从理论上讲，该研究明确揭示了由 Fe、Ni、Co 和 Cu 组成的四元中等熵 PBA （Q-ME-PBA） 在 K+ 离子相互作用期间表现出最小的晶格体积变化和低扩散势垒。这使 Q-ME-PBA 具有诱导显着 3D 晶格畸变的良好能力，使材料能够承受 K+ 离子运动期间的结构变化并增强相稳定性。因此，利用结构和成分优势，所得的 Q-ME-PBAs 阴极表现出卓越的循环性能，在 0.25 C 下循环 300 次后仍保持超过 90% 的容量保持率，初始库仑效率高达 94.4%，即使在 3.75 C 下超长 10 000 次循环 147 天后仍保持 74.7% 的容量。值得注意的是，与硬碳和石墨负极配对的全电池显示出出色的循环稳定性和倍率能力。本研究为通过中等熵晶格工程为高级 PIB 构建高性能和耐用的阴极绘制了新的设计方向。