Alpaca manure–derived carbon functionalized with nickel and vanadium oxides for supercapacitors

Chapia-Calderón L.; Alarcón-Arroyo M.I.; Hurtado Butrón F.J.; Araujo M.E.; Mello A.; Arias-Pinedo O.M.; Alviar Suarez M.I.; Gualdron-Plata A.P.; Martins V.L.; Baena-Moncada A.M. · New Journal of Chemistry (2026) · DOI: 10.1039/d6nj01261b

Resumen

Metal oxide–carbon composites were synthesized using activated carbon derived from alpaca manure as a sustainable precursor, functionalized with vanadium and nickel oxides (VNiO) for supercapacitor applications. VNiO nanocomposites were synthesized by a hydrothermal route using nickel glycerolate and ammonium metavanadate with controlled Ni : V ratios (1 : 1, 1 : 2, 2 : 1), while polymer-assisted methods employing urea–formaldehyde and urea–glycerol produced VNiO-NC and VNiO-UG variants. These oxides were subsequently supported on activated carbon to obtain AC/VNiO composites. TEM revealed nanoscale features ranging from sub-nanometer clusters (0.37 nm) to nanoparticles of 3.32 nm, whereas XPS confirmed the presence of C, V, Ni, O, and trace P species, together with mixed V3+/V4+/V5+ oxidation states. Raman analysis further showed that increasing oxide content promotes higher sp2-graphitic ordering within the carbon matrix. Electrochemical tests (cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) in 1.0 mol L−1 KOH) performed in symmetric two-electrode coin cells yielded device-level specific capacitances of 9.2–12.9 F g−1 at 5 mV s−1. EIS analysis using Brug's formula reveals that the micropore capacitance is the dominant contributor to total capacitance and is strongly influenced by the synthesis route, whereas the mesopore capacitance is independent of oxide composition. AC/VNiO-UG exhibited the highest specific capacitance and the lowest internal resistance, retaining ∼90% of its charge after 50 000 charge–discharge cycles. These results underscore an efficient, low-cost, and scalable approach for producing biomass-derived carbon–metal oxide nanocomposites, offering promising potential for durable and sustainable energy storage technologies. This journal is © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique, 2026.

Instituciones: Universidad Nacional de Trujillo; Universidad Nacional de Ingeniería