Carbon coated 1 T/2H MoS2 nanosheets on carbon cloth for high-performance flexible supercapacitor with superior mechanical stability

Abstract

High-performance flexible energy storage devices with excellent mechanical stability are essential for flexible electronic devices. Molybdenum disulfide (MoS₂) is a promising candidate for flexible supercapacitor electrode materials owing to its relatively high theoretical specific capacitance and mechanical flexibility. However, poor structural stability during electrochemical reactions significantly hinders its practical application in flexible supercapacitors. Carbon coatings have been regarded as the effective ways to improve the structural stability. In this study, carbon-coated 1 T/2H MoS₂ nanosheets on carbon cloth have been prepared for flexible supercapacitor applications with high cycling performance and mechanical stability. Field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy measurement results reveal that a gentle carbon coating process avoids the transformation from 1 T to 2H MoS₂ phase. As expected, carbon coated 1 T/2H MoS₂ electrode exhibits the highest specific capacitance of 443 mF cm⁻² at 1 mA cm⁻² and excellent cycling stability with 109 % capacity retention after 10,000 cycles. The as-assembled flexible symmetric supercapacitor shows high specific capacitance of 108.3 mF cm⁻² and maintains about 85 % cycling stability after 10,000 cycles. More significantly, the device shows superior flexibility and mechanical stability with 113 % capacitance retention after 5000 bending cycles, suggesting its great potential application in flexible electronic devices.