Microwave synthesis of nitrogen-doped mesoporous carbon/nickel-cobalt hydroxide microspheres for high-performance supercapacitors

A novel microsphere-like nitrogen-doped mesoporous carbon/nickel-cobalt layered double hydroxide (NMC/NiCo-LDHs-M) composites were successfully synthesized for the first time via a facile and costeffective microwave method. The NMC/NiCo-LDHs-M electrode displays outstanding pseudocapacitance performances, including a high specific capacitance (2498 F g(-1) at 1 A g(-1)), excellent rate capability and good charge-discharge stability, owing to the large surface area, appropriate pore size, rich mesoporous volume, low reaction resistance and high nitrogen amount. Moreover, an asymmetric supercapacitor using NMC/NiCo-LDHs-M as positive materials and NMC as negative materials was assembled to further investigate the electrochemical performances of NMC/NiCo-LDHs-M, which exhibited a high specific capacitance of 272.6 F g(-1) at 1 A g(-1) and outstanding electrochemical capacitance retention of 87.2% of initial capacitance after 10,000 cycles. These results indicated that the NMC/NiCo-LDHs-M microspheres were promising materials for high-performance supercapacitors and the microwave method was a potential approach for the design and preparation of diverse supercapacitor materials. (C) 2016 Elsevier B.V. All rights reserved.