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Molybdenum disulfide (MoS2)‐based electrode materials can exhibit a pseudocapacitive charge storage mechanism induced by nanosized dimension of the crystalline domains, which is why control over material structure via synthesis conditions is of significance. In this study, we investigate how the use of different sulfide precursors, specifically thiourea (TU), thioacetamide (TAA), and L‐cysteine (LC), during the hydrothermal synthesis of MoS2, affects its physicochemical, and consequently, electrochemical properties. The three materials obtained exhibit distinct morphologies, ranging from micron‐sized architectures (MoS2 TU), to nanosized flakes (MoS2 TAA and LC). While all three synthesized samples exhibit pseudocapacitive Li+ intercalation properties, the capacity retention of the latter two consisting of nanosized flakes is further improved at high cycling rates. The individual charge storage properties are analyzed by operando X‐ray diffraction, dilatometry, and 3D Bode analysis, revealing a correlation between the morphology, porosity, and the electrochemical intercalation behavior of the obtained electrode materials. The results demonstrate a facile strategy to control MoS2 structure and related functionality by choice of hydrothermal synthesis precursors. [ABSTRACT FROM AUTHOR]

The use of a pyrite‐like structure transition metal dichalcogenides (TMDs) such as NiS2 is not reported as frequently as layered structured TMDs in electrochemical capacitors. Our study shows a reduced graphene oxide (rGO) preparation and its further use as a substrate for the deposition of NiS2 during the hydrothermal reaction. The influence of pH for the GO solution on the structural and textural properties of the resultant rGO was explained in detail by using Raman spectroscopy, UV, X‐ray diffraction (XRD), scanning electron microscopy (SEM) and nitrogen sorption at 77 K. The electrochemical response of the rGO samples obtained from various pH solutions was studied and compared in symmetric two electrode Swagelok® cells. As a result, rGO pH 12 was chosen for further modification with NiS2. The average size of the crystallites, and electronic structure of the rGO/NiS2 composite have been determined. The effect of the NiS2 content in the composite on the electrochemical results was further investigated. It occurred that 5 wt % NiS2 in the composite was sufficient for a significant improvement of the capacitive response. Interestingly, an asymmetric cell with rGO/5 wt % NiS2 working as a positive electrode and rGO pH 12 as a negative electrode was able to reach a high capacitance of 165 F g−1 at 0.2 A g−1 with 92 % coulombic and 79 % energetic efficiency. [ABSTRACT FROM AUTHOR]