Pseudocapacitive materials have been employed in supercapacitors owing to their high specific capacitance. Nevertheless, high-level ultrafast capabilities are emphasized to overcome their rapid capacitance degradation under ultrafast-rate ion diffusion conditions. We demonstrated rational H2O deintercalation effects on cobalt vanadium oxide hydrate (CVOH) with increasing temperature. As the temperature increases to 200 ℃, CVOH undergoes a partial amorphization and exists in a mixed state of hydrated and dehydrated phases. As the temperature increases to 500 ℃, CVOH recrystallizes into the CVO phase through a complete deintercalation of H2O molecules. Such acceleration of H2O deintercalation leaves functionalized hydroxyl groups at the vertex oxygens, promoting binding affinity with electrolyte ions. Moreover, the crack propagation is accelerated on the CVO surface, resulting in a nano-split morphology from the surface to the interior of CVO particles that enlarges the contact area between the CVO and electrolyte. As the temperature increases to 800 ℃, H2O molecules re-intercalate and carbon bridged covalent bonds are formed between the CVO interlayers, resulting in particle coarsening. Owing to the rational H2O deintercalation effects on CVOH, CVO subjected to temperature at 500 ℃ maintained notable specific capacitance retention even under the ultrafast ion diffusion conditions (137.9 F/g at 500 mV/s).

中文翻译：

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用于超快储能装置的钴钒水合物的合理 H2O 脱嵌效应


由于赝电容材料具有高比电容，因此已被用于超级电容器。尽管如此，本文还强调了高水平的超快能力，以克服它们在超快速率离子扩散条件下的电容快速退化。我们证明了随着温度的升高，H2O 对钴氧化钒水合物 （CVOH） 的合理脱嵌效应。当温度升高到 200 °C 时，CVOH 发生部分非晶化，并以水合相和脱水相的混合状态存在。当温度升高到 500 °C 时，CVOH 通过 H2O 分子的完全脱嵌重结晶到 CVO 相。H2O 脱嵌的这种加速在顶点氧处留下官能化的羟基，促进与电解质离子的结合亲和力。此外，裂纹在 CVO 表面的扩展加速，导致从 CVO 颗粒表面到内部的纳米分裂形态，从而扩大了 CVO 和电解质之间的接触面积。当温度升高到 800 °C 时，H2O 分子重新嵌入，并在 CVO 夹层之间形成碳桥共价键，导致颗粒粗化。由于 H2O 对 CVOH 的合理脱嵌效应，即使在超快离子扩散条件下（500 mV/s 时为 137.9 F/g），CVO 在 500 °C 温度下也能保持显着的比电容保持。