A flexible carbon nanotube//zinc based aqueous zinc ion hybrid micro-supercapacitor with wide voltage window

Abstract

Recently, in order to satisfy the fast development of micro-supercapacitors that require both with excellent energy density and power density, zinc ion hybrid capacitors have garnered significant attention. Herein, a novel configuration of zinc-ion hybrid micro-supercapacitor with good mechanical flexibility has been assembled via carboxylated carbon nanotube (CNT) capacitor-type cathode and electrodeposited zinc (Zn) battery-type anode. The device demonstrates satisfying electrochemical characteristics, featuring an extensive operating voltage window of 1.8 V, and achieving a large areal capacity of 73 mF/cm² under 0.34 mA/cm². Additionally, it also displays excellent flexibility, good electrochemical stability with 85% capacitance retention rate and approximately 100% coulombic efficiency even under 5000 charging-discharging cycles. This work sheds light on the device design for Zn²⁺ storage, enabling the improvement of promising portable energy storage electronics.