MoS2 decorated carbon fiber yarn hybrids for the development of freestanding flexible supercapacitors

Abstract Academic and industrial efforts have focused on developing energy storage devices for wearable and portable electronics using low-cost, scalable, and sustainable materials and approaches. In this work, commercially available stretch-broken carbon fiber yarns (SBCFYs) were hybridized with mixed phases of 1 T and 2H MoS₂ nanosheets via conventional and microwave-assisted heating (CAH, MAH) without the use of binders to fabricate symmetric freestanding 1D fiber-shaped supercapacitors (FSCs). Electrochemical characterization performed in a three-electrode configuration showed promising results with specific capacitance values of 184.41 and 180.02 F·g⁻¹, at 1 mV·s⁻¹ for CAH and MAH, respectively. Furthermore, after performing 3000 CV cycles at 100 mV·s⁻¹, the capacitance retention was 79.5% and 95.7%, respectively. Using these results as a reference, symmetric 1D FSCs were fabricated by pairing hybridized SBCFYs with MoS₂ by MAH. The devices exhibited specific capacitances of approximately 58.60 ± 3.06 F·g⁻¹ at 1 mV·s⁻¹ and 54.81 ± 7.34 F·g⁻¹ at 0.2 A·g⁻¹ with the highest power density achieved being 15.17 W·g⁻¹ and energy density of 5.06×10^–4 Wh·g⁻¹. In addition, five 1D FSCs were hand-stitched and connected in series onto a cotton fabric. These supercapacitors could power a temperature and humidity sensor for up to six minutes, demonstrating the practicality and versatility of the prepared 1D FSCs for powering future electronic systems.