Hierarchical NiCo layered double hydroxide on reduced graphene oxide-coated commercial conductive textile for flexible high-performance asymmetric supercapacitors

Abstract

In this paper, commercial polyester conductive fiber coated with nickel and copper is used as flexible current collector. Graphene oxide is coated on the surface of polyester conductive fiber via simple physical deposition and reduced by two-step reduction method: thermal reduction and ascorbic acid-assisted reduction. Then, NiCo layered double hydroxide is electrodeposited on the surface of reduced graphene oxide. Polyester conductive fiber@reduced graphene/NiCo layered double hydroxide composite electrode exhibits excellent electrochemical performance with specific capacitance of 1220.5 F g−1 at a current density of 1 A g−1 and cycling stability of 84.1% capacitance retention after 5000 cycles at 8 A g−1. In addition, all-solid-state flexible supercapacitors are assembled with polyester conductive fiber@reduced graphene/NiCo layered double hydroxide composite and improved Fe2O3/N-doped graphene (282 F g−1 at 1 A g−1) as positive and negative electrodes, respectively. The asymmetric supercapacitors deliver very high energy density of 61.1 Wh kg−1 at a power density of 856.1 W kg−1 and remarkable cycling stability with 90.6% initial capacitance retained after 5000 cycles. In order to examine their bending life, a new swing device mainly composed of a shakable head and a fixed end is designed. After 3000 dynamic cycles, the capacitance retention can reach about 78%.