Electrochemical Capacitor Performance of Nanotextured Carbon/Transition Metal Dichalcogenides Composites

Transition metal dichalcogenides (TMDs) are emerging low-dimensional materials with potential applications for electrochemical capacitors (EC). Here, physicochemical and electrochemical characterizations of carbon composites with two sulfides ReS2 and FeS2 are reported. To enhance conductivity, multiwalled carbon nanotubes (NTs) serve as a support for ReS2 while 3D graphene-like network (3DG) is utilized for FeS2 deposition. Unique structure of carbon/TMDs composites allows a faradaic contribution of sulfides to be exploited. Capacitance values, charge/discharge efficiency, capacitance retention, charge propagation, cyclabilty, and voltage limits of EC with carbon/sulfide composites in aqueous neutral solutions (Li2SO4, Na2SO4) are analyzed. Special attention is devoted to energetic efficiency of capacitive charge/discharge processes. Structure-to-capacitance correlation for the composites with various TMDs loading is thoroughly emphasized. The more defected structure of layered NTs/ReS2 composite is responsible for the lower capacitor voltage (0.8 V) owing to quicker electrolyte decomposition. Additionally, the catalytic effect of Re for hydrogen evolution reaction plays a crucial role in EC voltage restriction. Contrary, the operating voltage of capacitor based on 3DG/FeS2 is able to be extended until 1.5 V in sodium sulfate electrolytic solution.

Automated summary

The physicochemical and electrochemical properties of carbon composites with two sulfides ReS2 and FeS2 are studied, showing potential applications for electrochemical capacitors. The structure-to-capacitance correlation for composites with various TMDs loading is emphasized, with ReS2 composite having lower capacitor voltage due to quicker electrolyte decomposition, while FeS2 composite can operate at extended voltage limits.