Abstract The operating voltage of aqueous hybrid capacitors are generally limited to 2 V due to the decomposition of water, which significantly impede the progress of energy density. Herein, the porous low-crystalline FeOx nanorod array on carbon cloth is prepared by the novel electrochemical Li+ pre-insertion method, and a 2.4 V high-voltage aqueous hybrid capacitor device is successfully obtained after matching with the nickel doped (Ni0.25Mn0.75)3O4@PPy nanoprisms array. The low-crystalline structure of FeOx preserved during the first Li+ insertion and space created via the elimination of low-crystalline Li2O dramatically provides sufficient electronic and ionic transfer channels. In addition, surface polypyrrole (PPy) stabilization is employed to further enhance electron conductivity and electrode stabilization. Benefitting from increasing active sites, fast ion diffusion and electron transfer the obtained low-crystalline FeOx@PPy electrode exhibits improved electrochemical performance, especially for capacitance and stability. Moreover, the aqueous hybrid capacitors (Ni0.25Mn0.75)3O4@PPy//FeOx@PPy device delivers a high energy density of 72.4 Wh kg−1 with the ultra-high voltage, and admirable cycling stability (94.7% retention after 4000 cycles). Our work highlights the novel electrochemical Li+ pre-insertion method to achieve superior low-crystalline electrodes materials and designs the high-voltage aqueous hybrid energy storage devices.

中文翻译：

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低结晶FeOx@PPy与(Ni0.25Mn0.75)3O4@PPy杂化构建2.4V高压水系混合电容器

摘要 由于水的分解，水性混合电容器的工作电压一般被限制在2 V，这显着阻碍了能量密度的进步。在此，采用新型电化学Li+预插入方法制备了碳布上多孔低晶FeOx纳米棒阵列，与掺杂镍的Ni0.25Mn0.25Mn0.25Mn0.25Mn0.25Mn0.25Mn0.25Mn0.25Mn0.25Mn0.25Mn0.25Mn0.25Mn0.25Mn0.25Mn0.200.100000000000000000000000000000000000方向您附近（含镍）的多孔低结晶FeOx纳米棒阵列，通过新型电化学Li+预插方法制备，并成功获得了2.4V高压水系混合电容器装置。 75)3O4@PPy 纳米棱镜阵列。FeOx 的低结晶结构在第一次 Li+ 插入和通过消除低结晶 Li2O 产生的空间期间保留，极大地提供了足够的电子和离子传输通道。此外，采用表面聚吡咯 (PPy) 稳定化以进一步提高电子电导率和电极稳定性。受益于增加的活性位点、快速的离子扩散和电子转移，获得的低结晶 FeOx@PPy 电极表现出改善的电化学性能，尤其是电容和稳定性。此外，水性混合电容器 (Ni0.25Mn0.75)3O4@PPy//FeOx@PPy 器件在超高电压下提供了 72.4 Wh kg-1 的高能量密度，以及令人赞叹的循环稳定性（4000 年后保持率达 94.7%循环）。我们的工作突出了新型电化学 Li+ 预插入方法，以实现优异的低结晶电极材料并设计高压水性混合储能装置。水性混合电容器 (Ni0.25Mn0.75)3O4@PPy//FeOx@PPy 器件具有 72.4 Wh kg-1 的高能量密度和超高电压，以及令人赞叹的循环稳定性（4000 次循环后保持率达 94.7%） . 我们的工作突出了新型电化学 Li+ 预插入方法，以实现优异的低结晶电极材料并设计高压水性混合储能装置。水性混合电容器 (Ni0.25Mn0.75)3O4@PPy//FeOx@PPy 器件具有 72.4 Wh kg-1 的高能量密度和超高电压，以及令人赞叹的循环稳定性（4000 次循环后保持率达 94.7%） . 我们的工作突出了新颖的电化学 Li+ 预插入方法，以实现优异的低结晶电极材料并设计高压水性混合储能装置。