The porous ZnCo2O4 nanosheets arrays as a binder-free electrode for high performance flexible supercapacitor materials

Abstract In this paper, the porous ZnCo2O4 nanosheets arrays (NAs)/carbon cloth (CC) were prepared for the first time as a binder-free anode by hydrothermal method. The anode electrode material shows multistage pore distribution and thus can provide numerous ways for the transport of ions and electrons. As a supercapacitor electrode, the flexible ZnCo2O4/CC electrode indicates a high specific capacitance (1790 F/g at the current density of 1 A/g), good rate performance, and excellent cycle properties (99.4% capacitance retention after 10000 cycles). Besides, the flexible electrode also displays good mechanical flexibility. The solid-state asymmetric flexible supercapacitor device was assembled taking the ZnCo2O4/CC electrode as the positive electrode and carbon nanotube (CNTs)/CC as the negative electrode. The asymmetric device delivers high energy density 47.1 Wh/Kg (power density 800 W/Kg) and power density 12000 W/Kg (energy density 28.3 Wh/Kg) with the potential window 0 V ~ 1.6 V. These results indicate the ZnCo2O4/CC flexible electrode with high electrochemical performance adjust for environmentally friendly and low-cost energy storage devices in the future.