Electrodeposited binder-free CoMn LDH/CFP electrode with high electrochemical performance for asymmetric supercapacitor

Carbon fiber paper (CFP)-supported CoMn-layered double hydroxide (LDH) or Co(OH)2 has been obtained using a simple and effective one-step electrodeposition. The binder-free CoMn LDH/CFP electrode displays a much enhanced pseudocapacitive performance with high specific capacitance (980 Fg−1 at 2 Ag−1), outstanding rate capability (79% capacitance retention with the current density from 2 to 32 Ag−1), and long-term life cycle (81% capacitance retention after 10,000 cycles at 32 Ag−1), much superior to that of pure Co(OH)2 (709 Fg−1, 65%, 79%). The improvement of electrochemical performance can be due to the enhancement of electrical conductivity and specific surface area of the freestanding CoMn LDH/CFP electrode, favoring electrochemical efficient and activity of the whole electrode material. And furthermore, an aqueous asymmetric supercapacitor fabricated with the CoMn LDH/CFP-positive electrode and the AC/CFP-negative electrode achieves a high specific capacitance of 53.5 Fg−1 at a wide potential window of 1.6 V and provides a high energy density of 19.1 Whkg−1 at a well power density of 400 Wkg−1. The facile preparation and excellent performance of the CoMn LDH/CFP make it a promising material for energy conversion/storage application.