Sodium 5-sulfosalicylate-assisted hydrothermal synthesis of a self-supported Co3S4−Ni3S2@nickel foam electrode for all-solid-state asymmetric supercapacitors

Abstract

Rational design and construction of self-supporting electrodes with high energy exporting densities promise a future of wearable and portable devices. Herein, we demonstrate that, for the first time, a one-pot hydrothermal method for the in-site growth of Co3S4 −Ni3S2 on nickel foam (NF) with the assistance of a chelating agent sodium 5-sulfosalicylate (SSS) (labeled as CS4−Ni3S2@F-SSS) for high-performance supercapacitors. Served directly as a self-supporting supercapacitor electrode, CS4−Ni3S2@F-SSS owns a specific capacitance of up to 2825.5 mF cm−2 at a corresponding 2 mA cm−2 current density and a commendable rate capability of 82% conducted within a current density domain of 2 − 40 mA cm−2 accompanied by good cyclability. More strikingly, the assembled tow-electrode (CS4−Ni3S2@F-SSS vs. active carbon (AC)@NF) all-solid-state asymmetric supercapacitor (ASC) is capable of reaching an energy density of 40.9 Wh kg−1 at a high power density of 1566.4 W kg−1 with excellent durability (92.8% retention after 2000 charge−discharge cycles at 8 mA cm−2), which are amongst the top of analogous ASCs in peer reports. Additionally, the possible factors that are accountable for the extraordinary supercapacitive performance of CS4−Ni3S2@F-SSS are discussed and analyzed.