High-Performance Flexible All-Solid-State Asymmetric Supercapacitors Based on Vertically Aligned CuSe@Co(OH)(2) Nanosheet Arrays

The developments of electrode active materials provide the opportunities for next-generation energy storage devices. The arrangement of electrode materials on the substrate has recently emerged as a promising strategy for preparing high-performance supercapacitors. Herein, we demonstrate a novel vertically aligned CuSe@Co(OH)(2) nanosheet arrays electrode for supercapacitor application. The materials are thoroughly characterized by structural and spectroscopic techniques. Electrochemical performance of CuSe@Co(OH)(2) nanosheet arrays are investigated in detail, which exhibit a specific capacitance as much as 1180 F g(-1) at a current density of 1 A g(-1). A flexible asymmetric all-solid-state supercapacitor is fabricated using CuSe@Co(OH)(2) nanosheet arrays as the positive electrode and activated carbon as the negative electrode. The device delivers a volumetric capacitance of 441.4 mF cm(-3) with maximum energy density and maximum power density is 0.17 and 62.1 mW cm(-3), as well as robust cycling stability (similar to 80.4% capacitance retention after 10 000 cycles), excellent flexibility, and mechanical stability. The excellent electrochemical performance can be attributed to its unique vertically aligned configuration.