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

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 (1916 F g(-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 10 A g(-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 120.67 F g(-1) at 0.5 A g(-1) and excellent cycling stability with 84.2% capacitance retention after 5000 cycles at a current density of 5 A g(-1). (C) 2016 Published by Elsevier Ltd.