A flexible Ni3S2/Ni@CC electrode for high-performance battery-like supercapacitor and efficient oxygen evolution reaction

Abstract

• A flexible Ni 3 S 2 /Ni@CC electrode is fabricated. • The all-solid-state ASC delivers 0.27 mWh cm −2 and superior mechanical flexibility. • The electrode demonstrates η 10 of 290.9–300.8 mV for OER at angles from 0 to 180°. • The good OER activity is supposed as the synergy effect of Ni 3 S 2 (OH) x and Ni 3 S 2 . The flexible electrodes with battery-like capacitive active materials or efficient electrocatalysts are highly desirable for flexible electronics and portable devices. Here we develop a highly flexible Ni 3 S 2 @Ni/CC electrode via a facile and scalable nickel electroplating and in-situ sulfuration route. When it acts as a supercapacitor electrode, the assembled all-solid-state hybrid supercapacitor delivers a high areal energy density of 0.27 mWh cm −2 at an areal power density of 4.90 mW cm −2 . Because of its superior mechanical flexibility, the assembled supercapacitor exhibits 88.1% retention of its initial capacitance after 2000 bending cycles from 0° to 90°. Furthermore, the Ni 3 S 2 @Ni/CC electrode exhibits high activity for oxygen evolution reaction (OER), achieving a benchmark of 10 mA cm −2 at a relatively low overpotential (η 10 ) of 290.9 mV with a Tafel slope of 101.26 mV dec −1 . Slight increments of 9.9 mV in η 10 and 6.55 mV dec −1 in Tafel slope are obtained even when the electrode is tested under a bending angle of 180°. Meanwhile what it delivers an excellent long-term durability for 30 h that is similar to the electrode without bending for OER. The flexible Ni 3 S 2 @Ni/CC electrode can be incorporated into wearable electronics and portable water-splitting cells.