EFFECT OF POLYVINYLPYRROLIDONE COATED SULFUR/REDUCED GRAPHENE OXIDE (S/rGO) TO THE ELECTROCHEMICAL IMPEDANCE FOR LITHIUM SULFUR BATTERY

• Main Author: SETIAWAN (NIM : 20216040), BRAMIANTO
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/26144
• Institution: Institut Teknologi Bandung

Elemental sulfur is one of the most attractive cathode active material in lithium batteries because of its high theoretical specific capacity. However, its practical application has been limited by several problems such as cycle life and low efficiency. In this study, we produced the composite of polyvinylpyrrolidone-sulfur on reduced graphene oxide (S/rGO/PVP) for lithium-sulfur battery. Reduced graphene oxide was used to increase conductivity both ionic and electronic conductivity electrode because of poor conductivity of sulfur (5 x 10-30 S/cm). Graphene oxide (GO) was synthesized using the modified Marcano's and Hummer's method. Sulfur was fabricated using a dissolution-crystallization method. In addition, the microwave was used to reduce the graphene oxide and to impregnate sulfur into rGO. In this research was used two variations. The first variation is the addition of PVP mass to sample (0%, 50%, 67%, and 75%) and the second variation is the time of microwave in low mode (10 minutes, 20 minutes, and 30 minutes). XRD characterization showed that sulfur, rGO and PVP crystals were formed. It was supported by SEM images that showed the characteristic of rGO and FTIR graph that the functional group of rGO, PVP and sulfur have been obtained. From TEM image showed the sulfur particles that had particles size 12,79 nm. The effect of coating and microwave radiation in electrode performances were investigated using an Electrochemical Impedance Spectroscopy (EIS) and four-point probe. In this research, battery device was made. From measurement battery using manual measurement showed that battery has specific capacity in 2 hours (discharge) 20,985 mAh g^(-1) and specific energy 37,193 Wh 〖kg〗^(-1). In this measurement, specific capacity and energy are not the totals that battery had due to the limited of measurement media that can only 2 hours measurement.