Facile preparation of Ni–Mn layered double hydroxide nanosheets/carbon for supercapacitor

Two kind of carbon materials including activated carbon (AC) and acetylene carbon black (AB) were used in situ combine with Ni-Mn layered double hydroxide (LDH) nanosheets as supercapacitor electrode materials by a facile hydrothermal method. For comparison, pure LDH nanosheets, LDH/AC and LDH/AB binary flower-like composites were synthesized, and meanwhile, the study of their structures, morphologies and electrochemical properties was conducted. It turned out that LDH/AB composite exhibited the highest specific capacitance of 1984 F g−1 at the current density of 1 A g−1, preferable rate capability due to the flower-like structure and higher specific surface area. Besides, LDH/AB composite and activated carbon electrodes were chosen to fabricate the asymmetric supercapacitor (ASC) which showed superior cyclic life (75% specific capacitance retention after 4000 cycles) and a high energy density of 42 Wh kg−1 at the power density of 400 W kg−1.