Low-cost coin-cell supercapacitors based on waste graphite from spent dry-cell batteries

• Main Author: Vitto, Remuel Isaac M.
• Format: text
• Language: English
• Published: Animo Repository 2023
• Subjects: Graphene; Physics
• Online Access: https://animorepository.dlsu.edu.ph/etdm_physics/9
• Institution: De La Salle University

In this study, graphite rods were extracted from dry-cell batteries and processed for chemical activation using potassium hydroxide. Prior to activation, the filtered graphite powder displayed a surface morphology of highly graphitic small stratified particles with a diameter of around 5 µm to 30 µm. While the surface morphology of the activated carbon surprisingly had no visible pore formation, it appears to have developed into thin flakes. The elemental composition and chemical composition of the activated carbon have been observed to be similar to graphene oxide, in agreement with its surface morphology. Partial oxidation and alkali metal intercalation in the interplanar spacings with exfoliation into thin layers have resulted in the chemical activation of graphite into exfoliated oxidized graphite layers. The chemically activated carbon was then utilized for the fabrication of supercapacitor electrodes and coin-cell supercapacitors modified with nickel oxide and reduced graphene oxide composite. Increased potential window and higher overall current readings were observed on a 2:1 ratio due to the redox reaction capability of nickel oxide and fast ion transport of reduced graphene oxide. The electrochemical performance of both the supercapacitor electrode and the coin-cell supercapacitor displayed excellent electric-double layer capacitance behavior and fast ion transfer kinetics between the electrode and electrolyte surface. The specific capacitance for both the supercapacitor electrode and the coin-cell supercapacitor was calculated to be 27.8 F g-1 and 20.10 F g-1 at a current density of 0.1 A g-1, respectively. The highest energy density was calculated to be 40.20 Wh/kg at a power density of 1,440 W/kg.