Design and synthesis of nitrogen-doped hexagonal NiCoO nanoplates derived from Ni-Co-MOF for high-performance electrochemical energy storage

Abstract In order to further improve the potential application of nickel-cobalt oxide (NiCoO) in supercapacitors, we use controlled calcination of different Ni-Co-MOF ([NiCo(HBTC)(4,4′-bipy)]) composites to obtain five kinds of nickel doped NiCoO (N-NiCoO) with different Ni/Co molar ratio. These N-NiCoO materials with unique hexagonal nanoplates structure, high specific surface area and high porosity indicate high and stable electrochemical activity. In particular, N-NiCoO-2 with a Ni/Co molar ratio of 2:1 exhibits the highest 945.79 F/g specific capacitance at 1 A/g and a high cycle stability of only 6.7% attenuation after 5000 cycles. Apart from the certain percentage of NiCoO with higher conductivity, nitrogen doping provides more reactive sites and the specific porous hexagonal nanoplates structure of the product itself accelerate electron transfer and promote electrolyte diffusion can more effectively enhance the electrochemical performance. Therefore, N-NiCoO synthesized via a simple method exhibit exciting potential and can be used as an electrode material for supercapacitors with good performance.