This article reports the first instance of exploring a chemically Zn(II) preinserted organic–inorganic hybrid material [vanadyl ethylene glycolate or VEG, (VO(CH₂O)₂)] as an efficient cathode for rechargeable zinc-ion batteries (ZIBs). The control VEG electrode synthesized by a glycothermal process showed a modest specific capacity of 157 mAh/g at 0.1 A/g current density, however, suffered from poor rate capability and cycle stability due to structural dissolution. Chemically Zn(II) preinsertion into VEG (Zn-VEG) catalyzed the Zn²⁺ intercalation in the Zn-VEG cathode with a significantly decreased charge transfer resistance, resulting in high discharge capacity of 217 mAh/g (at 0.1 A/g) accompanied by excellent rate capability with ∼50% capacity retention on increasing the current by 50 times. A first-principles-based hybrid density-functional theory (DFT) study revealed that the electronic structure of the Zn-intercalated VEG is thermodynamically stable, indicating an energetically favorable Zn-ion intercalation process. The Zn(II) preinserted VEG cathode allowed faster ionic diffusion (D_Zn²⁺ in the order of 10^–9 cm²/s), and the diffusion controlled process was the major contributor (∼66.9%) to the overall capacity at low scan rate (0.1 mV/s) and remained significant (43.8%) even at high scan rate of 0.8 mV/s. Furthermore, the Zn(II) preinsertion in the VEG could act as a bridge to hold the VEG layers firmly. This provides the desired structural stability to the Zn-VEG cathode during a continuous Zn²⁺ insertion/deinsertion process, resulting in excellent cycle stability with only ∼0.005% capacity loss per cycle over 2000 cycles (at 4 A/g) while maintaining a high columbic efficiency of 99.9% throughout the cycles. The high capacity accompanied by excellent rate capability and cycle stability supports the as-prepared Zn(II) preinserted organo-vanadyl hybrid electrode to be a potential cathode material for ZIBs.

中文翻译：

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Zn（II）预先插入的有机钒杂化阴极构成的水性锌离子电池的插层存储容量的催化

本文报道了探索化学预插入锌（II）的有机-无机杂化材料[钒酸乙二醇酯或VEG（（VO（CH ₂ O）₂）]]作为可充电锌离子电池（ZIBs）的有效阴极的首次实例。 。通过糖热法合成的对照VEG电极在0.1 A / g的电流密度下显示出适度的比容量157 mAh / g，但是由于结构溶解，其速率能力和循环稳定性较差。化学上将Zn（II）预插入VEG（Zn-VEG）催化Zn ²⁺插在Zn-VEG阴极中，显着降低了电荷转移电阻，导致217 mAh / g（0.1 A / g）的高放电容量，同时具有出色的倍率能力，将电流增加50倍时保留了约50％的容量。一项基于第一原理的混合密度泛函理论（DFT）研究表明，锌插层VEG的电子结构是热力学稳定的，表明在能量上有利的锌离子插层过程。预先插入Zn（II）的VEG阴极可实现更快的离子扩散（D _Zn ²⁺约为10 ^–9 cm ²/ s），并且在低扫描速率（0.1 mV / s）时，扩散控制过程是总容量的主要贡献者（〜66.9％），即使在0.8 mV / s的高扫描速率下，扩散控制过程仍然是显着（43.8％）。此外，在VEG中预先插入Zn（II）可以充当牢固固定VEG层的桥梁。这在连续的Zn ²⁺插入/插入过程中为Zn-VEG阴极提供了所需的结构稳定性，从而产生了出色的循环稳定性，在2000次循环（4 A / g）下，每个循环仅损失约0.005％的容量，同时保持了在整个循环过程中99.9％的高哥伦比亚效率。高容量以及出色的倍率性能和循环稳定性支持将所制备的预先插入的Zn（II）插入的有机钒基杂化电极用作ZIBs的潜在阴极材料。