Flexible asymmetric supercapacitors based on NiCo2O4 in a neutral electrolyte achieving 2.4 V voltage window

摘要

Flexible and high energy density supercapacitors have been received extensive attention due to their suitability as the power supply for wearable and portable electrical devices. However, it is still a great challenge to fabricate devices with simultaneously flexibility, high energy density and voltage window in a neutral electrolyte. Herein, we demonstrated a high-efficiency supercapacitor with dense NiCo2O4 nanosheets in Na2SO4 neutral electrolyte, achieving 1.2 V voltage window based on a single electrode, and 2.4 V for an assembled asymmetric system. The device shows an impressive capacitance of 120 F g(-1) at current density of 1 A g(-1), as well as an excellent cycling performance of 79.4% capacitance retention after 10,000 cycles. Meanwhile, the flexible ASC shows highly mechanical flexibility and impressive energy density, suggesting the great potential of the applications in flexible energy storage devices. (C) 2020 Elsevier B.V. All rights reserved.