A novel study on chronoamperometry electrodeposition of hexagonal boron nitride with Eucalyptus grandis-derived activated carbon for supercapacitor applications

Hellen Ngunya Mutua, University of Pretoria, South Africa
Delvina Japhet Tarimo, University of Pretoria, South Africa
Gift Rutavi, University of Pretoria, South Africa
Vusani Maphiri, University of Pretoria, South Africa
Julius Mwabora, University of Nairobi, Kenya
Robinson Musembi, University of Nairobi, Kenya
Ncholu Manyala, University of Pretoria, South Africa

Abstract

Activated carbon (AC) and hexagonal boron nitride (hBN) electrodes were successfully synthesized from Eucalyptus grandis tree bark and a mixture of boric acid and urea in the ratio of 2:3, respectively. The optimal composite hBN/AC-1:0.05 electrode was prepared by chronoamperometry electrodeposition at an optimal potential of 0.45 V for 60 min. The prepared electrodes were analyzed using Raman spectroscopy, Fourier Transform Infrared (FTIR), X-ray diffraction (XRD), Scanning Electron Microscope (SEM), and Energy Dispersive X-ray spectroscopy (EDS). Half- and full-cell setups were used to investigate the as-prepared AC, hBN, and hBN/ AC composite electrodes in 3 M KOH for electrochemical characterization. A supercapacitor was assembled using hBN/AC-1:0.05//AC. The device displayed a specific energy of 24.1 Wh/kg and a corresponding specific power of 1025 W/kg at 1 A/g in a potential window of 1.6 V. Furthermore, the developed device demonstrated a coulombic efficiency of 99.4 % and a capacity retention of 76.3 % after 10,000 GCD cycles at 5 A/g. The results of hBN/AC-1:0.05//AC contribute to the scientific community by highlighting the importance of biomass recycling (Eucalyptus grandis tree bark) and providing a simple approach to producing a composite material for energy storage.