Carbon-coated Hierarchical Ni–Mn Layered Double Hydroxide Nanoarrays on Ni Foam for Flexible High-capacitance Supercapacitors

Abstract

Hierarchical nanoarchitecture and composition can offer preponderances for enhancing pseudocapacitor performances. This paper reports on the three-dimensional hierarchical carbon-coated Ni–Mn layered double hydroxide on nickel foam (LNC) electrode material prepared via a facile two-step hydrothermal reaction. The resulting performance of the LNC composite material has high specific capacitance (1916Fg−1) and good cycling stability (91% retention after 5000 charge–discharge cycles). Moreover, the material can be directly used as an integrated flexible electrode with excellent rate capability (79.5% retention at 10Ag −1), which is significant in practical applications and large-scale syntheses. Furthermore, the LNC materials acting as a positive electrode for the asymmetric supercapacitor also exhibit high specific capacitance of 120.67Fg−1 at 0.5Ag−1 and excellent cycling stability with 84.2% capacitance retention after 5000 cycles at a current density of 5Ag−1.