Double metal ions synergistic effect in the Ni-doped Co(OH)(BA) nanobelts for enhanced supercapacitor performance

In this work, we report the synthesis and energy storage application of a Ni-doped hybrid inorganic-organic cobalt hydroxide ultrathin nanobelt with benzoate anion intercalation. The sample was prepared by a one-step hydrothermal method without any surfactants and adhesives. The layered cobalt hydroxide intercalated with benzoate anion is a promising cathode material due to the large interlayer distance, which improves ion flow efficiency. Importantly, Ni-doped Co(OH)(BA) enhances the electrochemical performance of supercapacitors, thereby achieving an ultra-high specific capacitance of 1664 F/g at 5 A/g, outstanding rate performance of 32.5% from 5 to 50A/g, low RESR of 4.8 Ω, and long capacity retention rate of 83% after 8000 cycles. Meanwhile, the combined Ni–Co(OH)(BA)//AC asymmetric supercapacitor device provides a high energy density of 47.5 Wh/kg at a power density of 850 W/kg with a long capacity retention of 91% after 8000 cycles. [Display omitted] •Ni–Co(OH)(BA) nanobelt was prepared by a one-step hydrothermal method.•Co(OH)(BA) intercalated with benzoate anion nanobelt provides a larger interlayer distance.•Co(OH)(BA) doped with highly active Ni species greatly improves the electrochemical activity of the material.•Ni–Co(OH)(BA)//AC device delivers high energy and power densities.