Modulating Sulfur Release Kinetics through Precursor Engineering for the Controlled Formation of 1 T /2H MoS2 Hybrids with Enhanced Charge Storage Properties

Abstract Molybdenum disulfide (MoS2) is a promising electrode material for electrochemical energy storage; however, its practical application is limited by the poor electrical conductivity of the thermodynamically stable 2H phase and the difficulty of achieving conductive 1T-rich structures through simple and scalable synthesis routes. In this work, a dual sulfur precursor strategy employing thioacetamide and thiourea was developed to regulate sulfur-release kinetics during hydrothermal synthesis, thereby controlling the phase evolution, microstructure, and electrochemical properties of MoS2. Structural characterization using X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy confirmed the formation of a mixed 1T/2H MoS2 hybrid containing approximately 39% metallic 1T phase at optimized precursor ratios. The dual precursor approach promoted enlarged interlayer spacing, hierarchical nanosheet assembly, and increased surface area (81 m2 g–1), resulting in a substantial enhancement in electrical conductivity from 4.5 × 10–5 to 1.3 × 10–1 S cm–1. The optimized 1T/2H hybrid delivered a specific capacitance of 353.8 F g–1 in 1 M H2SO4 and 89.4 F g–1 in 1 M KOH at a current density of 1 A g–1. Furthermore, an asymmetric supercapacitor assembled using the optimized material exhibited a capacitance of 309 F g–1, an energy density of 51.9 Wh kg–1, and a power density of 550 W kg–1, while retaining 94% of its initial capacitance after 10,000 charge–discharge cycles. These findings demonstrate that dual-sulfur precursor engineering provides a simple and effective route to tailoring phase composition, conductivity, and porous architecture in hydrothermally synthesized MoS2, for high-performance supercapacitor electrodes.