Reasonably designing the structure of composite materials and effectively increasing electroactive sites of electrode materials are considered as the promising approaches to enhance the electrochemical performance for supercapacitors. Herein, a double-layer layered double hydroxide nanosheet array grown on Ni foams is constructed through a facile two-step hydrothermal method. The as-prepared double-layer electrode materials including Ni, Co, and Mn elements possess large surface area and porosity; thus, it can increase the contact between electrolytes and the electrode materials, which leads to an increase in electroactive sites and high electrochemical performance. The double-layer electrode shows a high capacitance performance (2950 F/g at 1 A/g) and superior cycling stability (79% retention after 10,000 cycles at 10 A/g). In addition, the asymmetric NiCo/NiMn-LDHs//AC device is fabricated and manifests good capacity with excellent cyclic stability of 82.2% after 10,000 cycles.

合理设计复合材料的结构和有效增加电极材料的电活性位点被认为是提高超级电容器电化学性能的有效途径。在此，通过简便的两步水热法构建了在泡沫镍上生长的双层层状双氢氧化物纳米片阵列。所制备的Ni、Co和Mn元素的双层电极材料具有较大的表面积和孔隙率；因此，它可以增加电解质与电极材料之间的接触，从而增加电活性位点和高电化学性能。双层电极显示出高电容性能（1 A/g 时为 2950 F/g）和优异的循环稳定性（10 A/g 下 10,000 次循环后保留率为 79%）。此外，