Abstract 3D porous nickel nanosheet arrays (Ni-NSAs@Ni foam) are prepared by a facile hydrothermal process followed by an annealing treatment. The synthesized Ni-NSAs@Ni foam offered a mesoporous nano structure. First, Ni(OH)2 nanosheet arrays on Ni foam are synthesized by a hydrothermal process. Then, the Ni(OH)2 nanosheet arrays are transformed to Ni-NSAs@Ni foam via horizontal furnace tube. The Ni-NSAs@Ni foam electrode shows a high areal capacitance 4683.6 mF cm−2 at a current density of 1 mA cm−2, a capacitance retention of 80.8% at 10 mA cm−2, low internal resistance Rs~0.75 Ω and a retention ratio of 95.8% after 20,000 charge/discharge cycles. The capacitance of Ni-NSAs@Ni foam is much higher than that of the Ni(OH)2 nanosheet arrays. The outstanding electrochemical characteristic performances of the Ni-NSAs@Ni foam can be ascribed to the 3D porous nano structures of Ni-NSAs@Ni foam, which can offer short diffusion routes for charge carriers (electrons and ions), large active areas between the interface of the electrode/electrolyte and the low internal resistance between grown Ni-NSAs@Ni foam and the conductive current collector. Its hybrid supercapacitor device is assembled by using the Ni-NSAs@Ni foam as the positive electrode and activated carbon AC@Ni foam as the negative electrode. The hybrid supercapacitor device reaches an ultra-high energy density of 141.04 Wh kg−1 and a power density of 226.14 W kg−1 at 1 mA cm−2. The remarkable pseudocapacitive performance of Ni-NSAs@Ni foam electrode shows its great potential in applications of energy storage and conversion devices.

中文翻译：

---

3D 多孔镍纳米片阵列作为高能混合超级电容器的先进电极材料

摘要 3D 多孔镍纳米片阵列（Ni-NSAs@Ni 泡沫）是通过简单的水热工艺和退火处理制备的。合成的 Ni-NSAs@Ni 泡沫提供了介孔纳米结构。首先，镍泡沫上的 Ni(OH)2 纳米片阵列是通过水热法合成的。然后，通过水平炉管将 Ni(OH)2 纳米片阵列转化为 Ni-NSAs@Ni 泡沫。Ni-NSAs@Ni 泡沫电极在 1 mA cm−2 的电流密度下显示出 4683.6 mF cm−2 的高面电容，在 10 mA cm−2 下的电容保持率为 80.8%，低内阻 Rs~0.75 Ω 和20,000 次充放电循环后的保留率为 95.8%。Ni-NSAs@Ni 泡沫的电容远高于 Ni(OH)2 纳米片阵列。Ni-NSAs@Ni 泡沫优异的电化学特性可以归因于 Ni-NSAs@Ni 泡沫的 3D 多孔纳米结构，它可以为电荷载流子（电子和离子）提供短的扩散路径，在电极/电解质的界面以及生长的 Ni-NSAs@Ni 泡沫和导电集电器之间的低内阻。其混合超级电容器装置以Ni-NSAs@Ni泡沫为正极，活性炭AC@Ni泡沫为负极。混合超级电容器装置在 1 mA cm-2 下达到 141.04 Wh kg-1 的超高能量密度和 226.14 W kg-1 的功率密度。Ni-NSAs@Ni泡沫电极卓越的赝电容性能显示出其在能量存储和转换设备应用中的巨大潜力。