Nickel cobalt manganese ternary carbonate hydroxide nanoflakes branched on cobalt carbonate hydroxide nanowire arrays as novel electrode material for supercapacitors with outstanding performance

Abstract

In this work, for the first time we are reporting the development of a kind of high rate and long cycle life electrode composed of nickel cobalt manganese ternary carbonate hydroxide (NiCoMn-CH) ultrathin nanoflakes coated on Co-CH nanowire arrays (NWAs), which are directly generated on a nickel foam (NF) support. The hierarchical heterostructures are synthesized via a scalable two step solvothermal strategy without any adscititious surfactant and binder. The smart combination of Co-CH and NiCoMn-CH nanostructures in the nanowire arrays shows significant synergistic effect on the enhancement of the electrochemical performance of the as-fabricated supercapacitors. The as-obtained electrode exhibits excellent conductivity and high specific surface area, resulting in an unprecedented high specific capacitance (up to 3224F g^-1 at 1 A g^-1 in a three-electrode system) and an ultralong cycling stability (92.4% retention after 6000 successive charge-discharge cycles 5 A g^-1). Meanwhile, an asymmetric supercapacitor device assembled of the Co-CH@NiCoMn-CH hierarchical nanostructures as positive electrode and activated carbon (AC) as negative electrode delivers good energy density of 20.31 W h kg^-1 at the power density of 748.46 W kg^-1 in the operation window 0-1.5 V. This methodology could be generalized to the design of other novel structured nanomaterials for energy storage devices and other applications.

Keywords: Nanowire arrays; Ni-Mn-Co ternary carbonate hydroxide; Supercapacitor.