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

Otong Nurhilal,Risdiana Risdiana,Suci Winarsih,Dadan Sumiarsa,Sahrul Hidayat

doi:10.3390/su132212880

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.

Highlights

In the last few years, lithium-sulfur batteries (LSB) have received significant attention from researchers
The values of volume adsorbed of activated carbon from WH (ACWH)-400 were smaller than those of ACWH-600, indicating that the carbonization process at a temperature of 600 °C produces more carbon than the carboni
The values of volume adsorbed of ACWH-400 were smaller than those of ACWH-600, indicating that the carbonization process at a temperature of 600 ◦ C produces more carbon than the carbonization process at a temperature of 400 ◦ C

Summary

Introduction

In the last few years, lithium-sulfur batteries (LSB) have received significant attention from researchers. This is because the development of lithium-ion (Li-ion) batteries has experienced difficulties in increasing their capacity. It is difficult to achieve a specific capacity for lithium-ion batteries above 200 mA·h·g−1. Even in the case of lithium cobalt oxide (LiCoO2 ), which has a theoretical capacity of 274 mA·h·g−1 , only half of the Li-ions can be extracted because the other half is part of the matrix and total extraction of Li-ions results in lattice breakdown [1]. Lithium metal has a specific capacity of 3861 mA·h·g−1 , and sulfur has a specific capacity of 1675 mA·h·g−1.

Methods

Results

Conclusion