Unlocking High‐Performance Supercapacitor Behavior and Sustained Chemical Stability of 2D Metallic CrSe₂ by Optimal Electrolyte Selection

Abstract

Supercapacitors are energy storage devices with the ability to rapidly charge and discharge, making them a valuable complement to battery systems. To maximize their fast‐charging capabilities, identifying materials and methods to enhance their energy density is crucial. In this work, we carried out a comprehensive study of an emerging 2D dichalcogenide, CrSe2, as a supercapacitor material. We demonstrate that CrSe2 can be obtained at ambient temperature through deintercalation of a relevant KCrSe2 precursor using a 0.5 M solution of I2 in acetonitrile. Although CrSe2 decomposed in 1 M KOH, it was found to be chemically stable in common electrolytes such as H2SO4, Li2SO4, and Na2SO4. Despite low surface area CrSe2 reached a specific capacitance of 27 F g−1 in 1 M H2SO4 and, thus consistently outperformed high surface carbon black. Computational studies suggested that the metallic conductivity of CrSe2 was likely the primary factor contributing to the superior performance of this 2D chalcogenide over high surface carbon analogues.

Assessing Challenges of 2D-Molybdenum Ditelluride for Efficient Hydrogen Generation in a Full-Scale Proton Exchange Membrane (PEM) Water Electrolyzer

“…The peaks associated with the 1T′-monoclinic phase were still present (Figure S21a) and consistent with the XRD pattern of the sample before the electrolyzer testing. This confirmed that the bulk of the sample did not degrade or convert to other polymorphs, consistent with the behavior of related TMDCs in acidic conditions . However, Raman spectroscopy collected on 1T′-MoTe 2 /CC after galvanostatic electrolysis provided additional information.…”

“…This confirmed that the bulk of the sample did not degrade or convert to other polymorphs, consistent with the behavior of related TMDCs in acidic conditions. 46 However, Raman spectroscopy collected on 1T′-MoTe 2 /CC after galvanostatic electrolysis provided additional information. The band corresponding to the A g mode of 1T′-MoTe 2 was still observed at ∼160.2 cm –1 , consistent with the results of XRD.…”