Na_0.33V₂O₅‐type metal vanadates generally show better cycling stability than α‐V₂O₅ as a cathode in Li‐ion batteries, because they contain enough crystallographic voids that allow for lithium intercalation without significant structural deformation, but metal leaching upon cycling deteriorates their capacity retention. Here a new barium vanadate Ba_0.16(1)V₂O₅ is reported that does not undergo Ba leaching during cycling and shows a great promise for fast Li intercalation. Sr_0.15(1)V₂O₅ is isostructural to Na_0.33V₂O₅ (space group C2/m), while Ba_0.16(1)V₂O₅ adopts a new structure (space group P2₁/c), a derivative of Na_0.33V₂O₅. The framework of Ba_0.16(1)V₂O₅ consists of edge‐shared VO₆ octahedral layers and the VO₅ pyramidal bridge, generating unidirectional tunnels. Unlike the in‐plane arrangement of atoms in Sr_0.15(1)V₂O₅, the nonplanar arrangement in Ba_0.16(1)V₂O₅ makes the host framework more flexible and creates larger voids for Ba. Compared with the combination of displacement and intercalation mechanisms in the Sr_0.15(1)V₂O₅ cathode, Li intercalation looks dominant in the Ba_0.16(1)V₂O₅ cathode due to its increased flexibility. Hence, Ba_0.16(1)V₂O₅ exhibits improved cycling stability compared to Sr_0.15(1)V₂O₅, suggesting that lower symmetry leads to higher cyclic stability in the V₂O₅‐related compounds. This study illustrates how guest cations can tune the structural symmetry to modulate the reaction mechanism of electrode materials toward superior performances.

中文翻译：

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用于快速锂嵌入的新型钒酸钡BaxV2O5（x≈0.16）：较低的对称性，具有更高的柔韧性和电化学耐久性

的Na _0.33 V ₂ ø ₅型金属通常钒酸盐表现出更好的循环稳定性比α-V ₂ ø ₅如在锂离子电池的阴极，因为它们含有足够的晶体空隙，其允许锂嵌入而不显著结构变形，但金属浸出循环时会降低其容量保持能力。此处报道了一种新的钒酸钡Ba _0.16（1） V ₂ O ₅，其在循环过程中未经历Ba浸出，并显示出实现快速Li嵌入的巨大希望。Sr _0.15（1） V ₂ O ₅与Na _0.33 V ₂同构O ₅（空间组C 2 / m），而Ba _0.16（1） V ₂ O ₅采用新结构（空间组P 2 ₁ / c），即Na _0.33 V ₂ O ₅的衍生物。Ba _0.16（1） V ₂ O ₅的框架由边缘共享的VO ₆八面体层和VO ₅金字塔形桥组成，生成单向隧道。与Sr _0.15（1） V ₂ O ₅中原子的平面排列不同，Ba _0.16（1） V ₂ O _5中的非平面排列使主体框架更加灵活，并为Ba创建了较大的空隙。与在Sr _0.15（1） V ₂ O ₅阴极中置换和嵌入机制的组合相比，Li嵌入在Ba _0.16（1） V ₂ O ₅阴极中占主导地位，因为它具有更高的柔韧性。因此，与Sr _0.15（1） V ₂ O ₅相比，Ba _0.16（1） V ₂ O ₅表现出改善的循环稳定性。，表明较低的对称性会导致V ₂ O ₅相关化合物的循环稳定性更高。这项研究说明了客体阳离子如何调节结构对称性，以调节电极材料的反应机理，从而达到更高的性能。