Supercapattery and full-cell lithium-ion battery performances of a [Ni(Schiff base)]-derived Ni/NiO/nitrogen-doped carbon heterostructure

Abstract

In this work, a Ni/NiO/nitrogen-doped carbon (Ni/NiO/NC) nanocomposite was synthesized by a simple pyrolysis of a [Ni(Schiff base)] complex. The formation of the nanocomposite was confirmed by X-ray diffraction, Raman and Fourier transform infrared spectroscopy studies. X-ray photoelectron spectroscopy analysis revealed the chemical state of the elements present in the Ni/NiO/NC composite. Combining the merits of a supercapacitor and battery into a hybrid, a supercapattery device was fabricated in the form of a CR-2032 coin cell consisting of Ni/NiO/NC as the positive electrode and reduced graphene-oxide (rGO) as the negative electrode. The supercapattery device exhibited a high specific energy of 37 W h kg⁻¹ at a specific power of 560 W kg⁻¹ and high specific power of 2750 W kg⁻¹, while the energy density was as high as 18 W h kg⁻¹ with excellent cycling stability as well as coulombic efficiency. In addition, the lithium-ion storage performance of the Ni/NiO/NC nanocomposite was examined in half-cell and full-cell configurations. The full-cell exhibited a reversible capacity as high as 400 mA h g⁻¹ with an attractive cycling stability and coulombic efficiency. The excellent electrochemical performance was attributed to the large surface area and the conductive carbon network, which facilitates ion/electron transport with the shortened diffusion path.