Superior Capacitive Performance of Hydrochar-Based Porous Carbons in Aqueous Electrolytes

This is the accepted version of the following article: Fuertes, A. B. and Sevilla, M. (2015), Superior Capacitive Performance of Hydrochar-Based Porous Carbons in Aqueous Electrolytes. ChemSusChem, 8: 1049–1057. doi: 10.1002/cssc.201403267, which has been published in final form at http://dx.doi.org/10.1002/cssc.201403267. This article may be used for non-commercial purposes in accordance with the Wiley Self-Archiving PolicyBiomass-based highly porous carbons with excellent performances in aqueous electrolyte-based supercapacitors have been developed. The synthesis of these materials is based on the chemical activation of biomass-based hydrochar. The addition of melamine to the activation mixture leads to porous carbons with a porosity consisting of micropores/small mesopores. Furthermore, melamine promotes the introduction of nitrogen heteroatoms in the carbon framework, along with abundant oxygen functionalities, to improve the wettability. The materials produced in the presence or absence of melamine exhibit high specific capacitances in aqueous electrolytes (>270 F g−1 in H2SO4 and >190 F g−1 in Li2SO4). Additionally, the mesopores present in the melamine-based micro-/mesoporous carbons notably improve the ion-transport kinetics, especially in Li2SO4. Furthermore, in Li2SO4, they remain stable up to a cell voltage of 1.6 V; thus exhibiting superior energy and power characteristics than those in H2SO4.This research work was supported by the Spanish MINECO (MAT2012-31651). M. S. thanks the Spanish MINECO for her Ramón y Cajal contract.Peer reviewe