Harnessing Sargassum seaweed for the next generation of supercapacitors: a sustainable approach to advanced energy storage solutions

Abstract

Addressing the environmental, economic, and social challenges posed by Sargassum macroalgae invasions along the Mexican Caribbean coast; this study presents a low-cost, low-temperature procedure to obtain activated carbon (AC) capable of storing energy. The raw material, Sargassum natans and Sargassum fluitans, underwent a single chemical wash with HCl and deionized water prior to activation at temperatures of 200, 400, and 600 °C. Structural characterizations (Raman and FTIR) revelated modifications in the graphitic structure, achieving an ID/IG ratio of one and observing changes in C–O functional groups, which improved the material’s resistivity and conductivity. SEM analysis showed a porous network on the AC grains surfaces. Electrochemical studies CV, EIS, and GCD assessed the capacitive response in a two-electrode system, with findings indicating that higher activation temperatures reduce pseudocapacitive effects, yielding quasi-rectangular shapes indicative of electric double-layer capacitor (EDLC) behavior. A specific capacitance of approximately 12 mFg−1 was obtained for the 400 °C sample after only 60 cycles, making the carbonaceous material derived from sargassum highly suitable for energy storage applications.