Synthesis of ZnCo₂O₄/ZnO/CoO-modified bamboo fiber-derived activated carbon composites for enhancing supercapacitor...

To optimize the overall functionality of biomass-derived carbon materials in electrochemical applications, particularly with regard to specific capacitance, electrical conductivity, and cycling stability, this study proposes a composite design approach. Utilizing bamboo fiber-based activated carbon (BFAC) as the substrate allows for the precise tuning of the material's microstructure through hydrothermal calcination, thereby enabling the controlled deposition of ZnCo₂O₄/ZnO/CoO metal oxide nanoparticles. Meanwhile, the impact of hydrothermal treatment duration on the electrochemical characteristics of ZnCo₂O₄/ZnO/CoO@BFAC was investigated. It was found that the composite electrode material via a 9-hour hydrothermal process, demonstrated remarkable electrochemical properties. At a current density of 1 A g^-1, the material achieved a peak specific capacitance of 687 F g^-1. The synthesis of ZnCo₂O₄/ZnO/CoO@BFAC was verified by using characterization methods including XRD, XPS, SEM and TEM. Furthermore, the constructed asymmetric supercapacitor exhibits an energy density of 19.91 Wh·kg^-1 under a power density of 790 W·kg^-1. Concurrently, the material's capacitance retention was found to be 83 % effective after it underwent 5000 charge-discharge cycles at an electric current of up to 10 A g^-1. The aforementioned results demonstrate that the integration of nanostructured metal oxides with bio-derived activated carbon emerges as a potent and hopeful method for fabricating high-performance supercapacitors.