Facile route to achieve mesoporous Cu(OH)2 nanorods on copper foam for high-performance supercapacitor electrode

In this work, the three-dimensional (3D) mesoporous Cu(OH)2 nanorods were fabricated on copper foam via a facile and cost-effective surface oxidation method, a product that can be directly used as a binder-free electrode for supercapacitors. The synthesized 3D Cu(OH)2 nanorods demonstrate high surface area, uniform pore size distribution characteristics and 3D quasi-connect structures, and the copper foam substrate not only undertakes the role of current collector but also the copper source of the reaction. Therefore, the as-prepared electrode can provide numerous active sites for redox reactions, exhibit low intrinsic resistance and shorten the ions diffusion pathway. Benefiting from that, the following characteristics are obtained: high capacitance of 2.151 F cm−2, good rate capability of 88.3% retention upon increasing the current density by 10 times, good coulombic efficiency of 89.4% and good cycling durability of 97.3% retention after 5000 cycles. In addition, an asymmetric supercapacitor is assembled using the mesoporous Cu(OH)2 as positive electrode and activated carbon as negative electrode. The device delivers a high energy density of 4.152 mW h cm−3 and a high power density of 383.222 mW cm−3. The results suggest a great potential for fabrication of high performance energy storage devices.