Low-cost disordered carbons for Li/S batteries: A high-performance carbon with dual porosity derived from cherry pits

A micro- and mesoporous carbon obtained from cherry pit waste and activated with H3PO4 acid has been studied as the sulfur host for Li/S batteries. The carbon has a high specific surface area of 1,662 m2·g–1 (SBET) and micropore and mesopore volumes of 0.57 and 0.40 cm3·g–1, respectively. The S/C composite, with a sulfur content of 57% deposited by the disproportionate reaction of a S2O3 2− solution in an acid medium without an additional heating step above the S melting point, delivers an initial specific capacity of 1,148 mAh·g–1 at a current of C/16. It also has a high capacity retention of 915 mAh·g–1 after 100 cycles and a Coulombic efficiency close to 100%. The good performance of the composite was also observed under higher current rates and long-term cycling tests. The capacities delivered by the cell after 200 cycles were 707 and 410 mAh·g–1 at C/2 and 1C (1C = 1,675 mA·g–1), respectively, maintaining the high Coulombic efficiency. The overall electrochemical response of this carbon as the sulfur matrix is among the best reported so far among the other biomass-derived carbons, probably because of the micro- and mesopore system formed upon activation.