Abstract In this study we synthesized a vanadium (V)-containing metal–organic framework (MOF) and used it as a template to prepare V2O5 NPs. We used MIL-47, a V-containing MOF having uniform C and V distributions, as a precursor for the preparation of carbon-coated V2O5 (C@V2O5) samples through annealing. The C@V2O5 structures were readily dispersed in poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) to form stable solutions, allowing the deposition of C@V2O5 on various substrates through simple low-temperature solution-based processes. The uniform coating of carbon on V2O5 was useful for two reasons: (i) the outer layer enhanced the electronic conductivity of a V2O5 electrode and its corresponding electrochemical properties and (ii) based on the electrochemical quartz crystal microbalance (EQCM) analysis, the carbon coating served as a buffer layer that allowed Li+ ion transport, but blocked migration of solvent into the V2O5 electrode, thereby improving the dimensional and electrochemical stability. Compared with the bare V2O5, C@V2O5 exhibited excellent electrochromic (EC) performance, with an EC contrast of 45.8%, a mean response time of 3.4 s, and a coloration efficiency of 89.3 cm2/C. C@V2O5 also displayed higher cycling stability (80.6% retention after 5000 cycles) and highly reversible ionic transport during redox reactions, compared with those of the bare V2O5.

中文翻译：

---

来自金属有机骨架的碳包覆 V2O5 的增强电致变色性能

摘要 在本研究中，我们合成了一种含钒 (V) 的金属有机骨架 (MOF)，并将其用作模板来制备 V2O5 NPs。我们使用 MIL-47，一种具有均匀 C 和 V 分布的含 V MOF，作为通过退火制备碳涂层 V2O5 (C@V2O5) 样品的前体。C@V2O5 结构很容易分散在聚 (3,4-亚乙基二氧噻吩):聚苯乙烯磺酸盐 (PEDOT:PSS) 中形成稳定的溶液，通过简单的基于低温溶液的工艺使 C@V2O5 沉积在各种基材上。在 V2O5 上均匀涂覆碳有两个原因：（i）外层增强了 V2O5 电极的电子电导率及其相应的电化学性能；（ii）基于电化学石英晶体微量天平（EQCM）分析，碳涂层作为缓冲层，允许 Li+ 离子传输，但阻止溶剂迁移到 V2O5 电极，从而提高尺寸和电化学稳定性。与裸V2O5相比，C@V2O5表现出优异的电致变色（EC）性能，EC对比度为45.8%，平均响应时间为3.4 s，着色效率为89.3 cm2/C。与裸 V2O5 相比，C@V2O5 还显示出更高的循环稳定性（5000 次循环后保留 80.6%）和氧化还原反应过程中高度可逆的离子传输。EC 对比度为 45.8%，平均响应时间为 3.4 秒，着色效率为 89.3 cm2/C。与裸 V2O5 相比，C@V2O5 还显示出更高的循环稳定性（5000 次循环后保留 80.6%）和氧化还原反应过程中高度可逆的离子传输。EC 对比度为 45.8%，平均响应时间为 3.4 秒，着色效率为 89.3 cm2/C。与裸 V2O5 相比，C@V2O5 还显示出更高的循环稳定性（5000 次循环后保留 80.6%）和氧化还原反应过程中高度可逆的离子传输。