High Sulfur Content of Mesoporous Activated Carbon Composite Derived from Water Hyacinth

Abstract

Cathode composites with high sulfur content have become a concern to develop because they can improve the performance of lithium-sulfur batteries. The high sulfur content in the composite can be obtained from the carbon matrix, which has a high surface area and high electrical conductivity. Activated carbon made from biomass waste can be used as a carbon matrix due to its high surface area and ease of synthesis. In this study, activated carbon was prepared from water hyacinth (ACWH-600), which was carbonized at a temperature of 600 °C with a ZnCl2 activator. Activated-carbon–sulfur composite (ACWH-600/S) was synthesized by mixing activated carbon and sulfur in a ratio of 1:3. The characterizations performed for ACWH-600 and ACWH-600/S were N2 desorption–adsorption to determine the surface area, SEM to determine surface morphology, XRD to determine graphite structure, thermogravimetric analysis test to determine the sulfur content in the composite, and four-line probe conductivity to measure electrical conductivity at room temperature. The surface area, total pore volume, and pore diameter of ACWH were 642.39 m2 g−1, 0.714 cm3 g−1, and 2.22 nm, respectively, while the surface area, total pore volume, and pore diameter of ACWH-600/S were 29.431 m2 g−1, 0.038 cm3 g−1, and 2.54 nm. The conductivity value of ACWH-600 was 3.93 × 10−2 S/cm, while for ACWH-600/S, the conductivity value was 2.24 × 10−4 S/cm. The decrease in conductivity value after activated carbon added sulfur indicated the success of synthesizing a carbon matrix from water hyacinth with high sulfur content. The high sulfur content of 58 wt%, together with the acceptable conductivity value of composite ACWH-600/S, provide an opportunity to apply these composites as cathodes in lithium-sulfur batteries.