Defect-Induced 1T-MoS₂–PPy Composite for Supercapacitor Applications

Abstract

The development of highly conductive and electrochemically active electrode materials is crucial for advanced energy storage technologies. In this work, a defect-induced metallic 1T-MoS₂–polypyrrole (PPy) composite is developed as an efficient electrode material for supercapacitor applications. Controlled defect engineering introduces sulfur vacancies and lattice distortions within 1T-MoS₂, enhancing electronic conductivity, electrochemical active sites, and ion-accessible surface regions. The integration of PPy creates a conductive polymer network that suppresses MoS₂ nanosheet restacking, improves structural stability, and provides additional pseudocapacitive charge storage through reversible doping/de-doping processes. The synergistic interaction between defect-rich 1T-MoS₂ and PPy facilitates rapid electron transport, enhanced electrolyte ion diffusion, and accelerated Faradaic reactions, resulting in improved electrochemical performance. The optimized 1T-MoS₂–PPy composite delivers a specific capacitance of 1208 F g⁻¹, demonstrating enhanced charge storage capability due to the combined contribution of electric double-layer capacitance and Faradaic pseudocapacitance. Electrochemical impedance analysis confirms improved charge-transfer kinetics and efficient ion transport within the composite electrode. Furthermore, AFM-based surface analysis reveals increased nanoscale surface complexity after defect engineering and PPy incorporation, providing more electrochemically accessible active sites. The enhanced fractal characteristics are associated with improved electrolyte interaction and synergistic charge-storage mechanisms. These findings highlight defect-induced 1T-MoS₂–PPy composites as promising electrode architectures for high-performance supercapacitor applications.

Keywords: 1T-MoS₂; Polypyrrole; Supercapacitor