Abstract In this work, we demonstrate a facile, binder-free technique to fabricate 3D Cu2Se nano-cauliflower with 2D CuS nanosheets as a composite on Ni foam by co-electrodeposition technique for high-performance solid-state supercapacitor. The morphology of the composite (Cu2Se@CuS) was confirmed by the scanning electron microscope and the crystal phases of monoclinic Cu2Se and hexagonal CuS were obtained using X-ray diffraction technique. The Cu2Se@CuS composite delivered an ultra-high specific capacitance of 2727 F g−1, compared to its single compound material Cu2Se (1925 F g−1) and CuS (1156 F g−1), respectively at current density of 2.5 mA cm−2 in three-electrode configuration. Ni foam, as a binder-free conducting substrate, acts as uniform growth point for electrode materials and accelerates the transportation of ions throughout the electrode while the synergistic effect of Cu2Se and CuS and their efficient redox properties contribute to faster diffusion path for both electrolyte ions and electrons. Moreover, the assembled asymmetric solid-state supercapacitor Cu2Se@CuS// AC with PVA-KOH gel as supporting electrolyte delivered an excellent specific energy of 42.7 Wh Kg−1 (1.95 Wh cm−3) at specific power of 381 W kg−1 (17.55 W cm−3). The solid-state device achieved a good cyclic stability of 70.2% capacitance retention even after 8000 cycles. This technique of a simple co-electrodeposition method outlined in this work to engineer 3D/2D nanostructured electrode provides a potential strategy for fabricating high performance, free-standing energy storage devices.

中文翻译：

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轻松合成 3D/2D Cu2Se 花椰菜/CuS 纳米片复合材料作为高性能非对称固态超级电容器的无粘合剂电极

摘要 在这项工作中，我们展示了一种简便、无粘合剂的技术，通过共电沉积技术在高性能固态超级电容器上制备具有二维 CuS 纳米片的 3D Cu2Se 纳米花椰菜作为泡沫镍的复合材料。通过扫描电子显微镜确认复合材料（Cu2Se@CuS）的形貌，并使用X射线衍射技术获得单斜Cu2Se和六方CuS的晶相。Cu2Se@CuS 复合材料在 2.5 mA 的电流密度下分别提供了 2727 F g-1 的超高比电容，与其单一化合物材料 Cu2Se (1925 F g-1) 和 CuS (1156 F g-1) 相比cm−2 在三电极配置中。泡沫镍作为无粘合剂的导电基材，充当电极材料的均匀生长点并加速离子在整个电极中的传输，而 Cu2Se 和 CuS 的协同效应及其有效的氧化还原特性有助于加快电解质离子和电子的扩散路径。此外，组装的非对称固态超级电容器 Cu2Se@CuS// AC 与 PVA-KOH 凝胶作为支持电解质在 381 W kg-1 的比功率下提供了 42.7 Wh Kg-1 (1.95 Wh cm-3) 的优异比能量(17.55 W cm−3)。即使在 8000 次循环后，固态器件仍实现了 70.2% 的电容保持率的良好循环稳定性。在这项工作中概述的这种简单的共电沉积方法技术可以设计 3D/2D 纳米结构电极，为制造高性能、独立的储能设备提供了一种潜在的策略。