High-rate capability of supercapacitors based on tannin-derived ordered mesoporous carbons

Abstract

Ordered mesoporous carbons (OMCs) are produced by an easy, fast, and green surfactant-water-assisted mechanochemical mesostructuration (SWAMM) method, using only tannin, water, and Pluronic F127 as raw materials. OMCs are physically activated with CO2 to increase their surface area from ∼500 to ∼2000 m2 g–1 while maintaining the mesoporosity fairly unaltered, which allow studying the effect of the micropore size distribution on the performance of supercapacitors both in aqueous and organic electrolytes. Selected activated OMCs (AOMCs) reach maximum cell capacitance values of 37 and 27 F g–1, at 0.2 A g–1, in aqueous and organic electrolytes, respectively. High long-term stabilities over time and after continuous cycling are found for the tested AOMCs in both kinds of electrolytes. High-rate capabilities are achieved at high current densities with capacitance retentions up to 70% at 80 A g–1 and 44% at 40 A g–1 in aqueous and organic electrolytes, respectively, because of suitable pore size distribution that promotes ion diffusion into the electrodes, in particular for the material activated during 75 min.