In Situ Growth of Ni–Zn–Fe Layered Double Hydroxide on Graphene Aerogel: An Advanced Two‐in‐One Material for Both the Anode and Cathode of Supercapacitors

Abstract

The push toward high‐performance supercapacitors calls for the development of efficient pseudocapacitive negative electrode materials that can better match the high capacitance of the typical positive electrodes. Herein, a facile and one‐pot hydrothermal approach for the in situ growth of the nickel–zinc–iron layered double hydroxide (LDH) onto the graphene aerogel (GA) substrate is introduced. Proper selection of the metal precursors with prominent pseudocapacitive behavior over a wide potential range coupled with the excellent double‐layer capacitive and charge transport properties of the GA network results in an LDH–GA nanocomposite that displays outstanding supercapacitive performances as both negative (387 F g−1, 101 mA h g−1, at 1.0 A g−1) and positive (1235 F g−1, 103 mA h g−1) electrodes. An aqueous LDH–GA//LDH–GA device with a wide voltage window (1.55 V) that demonstrates a significantly enhanced specific capacitance (304 F g−1 at 1.0 A g−1), outstanding specific energy (95 W h kg−1), appreciable specific power (81 kW kg−1), along with 88% retention of the initial capacitance after 10 000 cycles, is also fabricated. The superior supercapacitive performance of the Ni–Zn–Fe LDH–GA nanocomposite over both negative and positive voltage ranges opens a promising pathway toward manufacturing high‐energy supercapacitors for state‐of‐the‐art applications.