The moderate working voltage and high capacity of transition metal dichalcogenides (TMDs) make them promising anode materials for aqueous calcium-ion batteries (ACIBs). However, the large radius and two charges of Ca²⁺ cause TMDs to exhibit poor performance in ACIBs. Therefore, effective regulation strategies are crucial for enabling the application of TMDs in ACIBs. Herein, MoS₂ with expanded interlayer spacing and an enriched 1T phase (ES-1T-MoS₂) is constructed by molecular engineering and reported as an anode material for ACIBs. Molecular engineering increases the capacity of MoS₂ from 29.4 to 91.2 mAh g^–1 and improves its rate performance from 20 to 76.1 mAh g^–1 at 2.0 A g^–1. ES-1T-MoS₂ also shows a −20 to 50 °C wide temperature working capability. Furthermore, the capacity improvement reasons and the calcium storage mechanism of ES-1T-MoS₂ are revealed through density functional theory calculations and in situ/ex situ characterizations. Finally, a “rocking-chair” aqueous calcium-ion pouch cell with a Prussian blue analogue cathode and ES-1T-MoS₂ anode is assembled. The pouch cell exhibits a life of 150 cycles with over 90.8% capacity retention at 0 and 25 °C. This work demonstrates that molecular engineering is an effective strategy to improve the calcium storage performance of TMDs and promotes the advancement of ACIBs.

中文翻译：

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分子工程构建具有扩大层间距和富集 1T 相的 MoS2，用于“摇椅”水性钙离子袋电池


过渡金属硫化物 （TMD） 的中等工作电压和高容量使其成为水系钙离子电池 （ACIB） 的有前途的负极材料。然而，大半径和 Ca ²⁺ 的两个电荷导致 TMD 在 ACIB 中表现出较差的性能。因此，有效的监管策略对于实现 TMD 在 ACIB 中的应用至关重要。在此，通过分子工程构建了具有扩展层间距和富集 1T 相的 MoS ₂ （ES-1T-MoS ₂ ），并报道了 ACIBs 的负极材料。分子工程将 MoS ₂ 的容量从 29.4 mAh g 增加到 91.2 mAh g ^–1 ，并在 20 A g ^–1 时将其倍率性能从 76.1 mAh g 提高到 2.0 mAh g ^–1 。ES-1T-MoS ₂ 还显示出 −20 至 50 °C 的宽温度工作能力。此外，通过密度泛函理论计算和原位/非原位表征揭示了 ES-1T-MoS ₂ 的容量提高原因和钙储存机制。最后，组装了一个带有普鲁士蓝类似物阴极和 ES-1T-MoS ₂ 阳极的“摇椅”水性钙离子软包电池。软包池的使用寿命为 150 次循环，在 0 °C 和 25 °C 下容量保持率超过 90.8%。 这项工作表明，分子工程是提高 TMDs 钙储存性能并促进 ACIBs 进步的有效策略。