Supercapacitors for storing energy from coffee bean waste

Abstract

Activated carbon (AC) was made from coffee bean waste, which was prepared by chemical activation, using potassium hydroxide (KOH) at 2 M as activating agent, with impregnation times of 24 and 48 h, temperatures carbonization of 600 and 700 ° C, once the activated carbon samples were obtained, they were doped with nickel oxide (NiO), in order to modify the electrical properties of CA, later they were characterized (physical adsorption of N2, FT-IR, XRD). The CA / NiO composites were prepared by the chemical method and electrodes were compacted into forms of self-consistent tablets, which were placed in a two-electrode cell using sulfuric acid (H2SO4) as electrolyte at 2 M. The electrochemical part was evaluated by means of Cyclic voltammetry and galvanostatic chronopotentiometry, obtaining the electrical behavior of the electrodes for their application in supercapacitors (SCS). Finally, the specific capacitance of the SCS was determined from CA / NiO, as a result it was obtained that the CA / NiO-48-700 ° C-KOH samples showed a maximum capacitance of: 405.405 F / g respectively. This proves that nickel oxide improved the properties of AC for use as electrodes in supercapacitors.