Synthesis and characterization of biodegradable starch/reduced graphene oxide-molybdenum disulfide ternary nanocomposite for energy storage applications

Abstract

A ternary nanocomposite of plasticized starch (PS), reduced graphene oxide (rGO), and molybdenum disulfide (MoS2) was prepared via an aqueous casting process, with MoS2 concentrations ranging from 0.25 wt.% to 1.00 wt.%. FTIR analysis confirmed the formation of new chemical bonds between PS, rGO, and MoS2, indicating strong interactions among them. XRD analysis revealed the reduction in crystallinity and defects in the nanocomposite. Cross-section FESEM images showed a layered structure. UV-vis spectroscopy demonstrated a reduction of optical bandgap from 4.71 eV to 2.90 eV, resulting from enhanced charge transfer between the layers and defect states. DC electrical analysis indicated a ten-fold decrease in resistivity. The contact angle of the nanocomposites decreased from 48.32˚ to 22.80˚, and then specific capacitance increased from 2.78 Fg-1 to 124.98 Fg-1 at a current density of 0.10 mAg-1. EIS revealed a significant reduction in charge transfer resistance from 4574 Ω to 0 Ω, facilitating ion transportation between the layers. The incorporation of MoS2 in the nanocomposite exhibited excellent stability, retaining about 80% of its capacitance up to 10,000 charging-discharging cycles. These findings make the nanocomposite promising for eco-friendly energy storage applications.