WS2/Mesoporous Carbon Nanostructures as a Bifunctional Electrode for All Quasi-Solid-State Supercapacitor and Oxygen Evolution Reaction

Abstract

2D transition-metal sulfides have developed as favorable electroactive materials for electrochemical energy storage and conversion applications. In this work, WS2/mesoporous carbon (MC) is developed by a one-step hydrothermal technique for supercapacitor and oxygen evaluation reaction (OER) application. However, the metal sulfides have poor rate and cyclic performance due to the aggregations between two layers of structures restricting their performance. The interaction between WS2 nanosheets and MC produces a synergistic effect, resulting in a decent electrochemical energy storage and conversion application. The synthesized materials used to prepare quasi-solid-state symmetric (QSSS) and asymmetric (QSSA) supercapacitor configuration enable the highest specific capacitance (CSP) of 305.45 F g−1 and 204.21 F g−1@ 10 mV s−1, respectively. Moreover, the specific energy and power density of QSSS and QSSA devices are 31.1 Wh kg−1 @824.95 W kg−1 and 24.74 Wh kg−1 @549.84 W kg−1, respectively. Additionally, the multifunctionality of the synthesized binary nanocomposite is also tested for OER. The composite shows a desirable over potential of 307 mV in 6 m KOH electrolyte, with a 69 mV dec−1 Tafel slope. The dual role of WS2/MC for energy storage and oxygen evaluation reaction conversion reveals the potential of metal sulfides.