Bacterial Nanocellulose from Komagataeibacter Medellinensis in Fique Juice for Activated Carbons Production and Its Application for Supercapacitor Electrodes

This paper presents the results obtained from the chemical activation of bacterial nanocellulose (BCN) using fique juice as a culture medium. BNC activation (BNCA) was carried out with H3PO4 and KOH at activation temperatures between 500 °C to 800 °C. The materials obtained were characterized morphologically, physicochemically, superficially, and electrochemically, using scanning electron microscopy, X-ray photoelectron spectroscopy (XPS), the physisorption of gases N2 and CO2 at 77 K and 273 K, respectively, cyclic voltammetry, chronopotentiometry, and electrochemical impedance spectroscopy (EIS). The samples activated with H3PO4 presented specific surface areas (SBET) around 780 m2 g−1, while those activated with KOH values presented specific surface areas between 680 and 893 m2 g−1. The XPS analysis showed that the PXPS percentage on the surface after H3PO4 activation was 11 wt%. The energy storage capacitance values ranged between 97.5 F g−1 and 220 F g−1 by EIS in 1 M H2SO4. The samples with the best electrochemical performance were activated with KOH at 700 °C and 800 °C, mainly due to the high SBET available and the accessibility of the microporosity. The capacitance of BNCAs was mainly improved by electrostatic effects due to the SBET rather than that of pseudocapacitive ones due to the presence of phosphorus heteroatoms.