Achieving high area capacitance of Ti3C2Tx//MnO2 flexible aqueous zinc-ion hybrid microsupercapacitors with wide operating voltage window

Abstract

Aqueous zinc-ion hybrid supercapacitors (AZIHSs) are extensively studied as a new kind of electrochemical energy storage devices that combine advantages of capacitors and batteries. It is highly desirable to develop AZIHSs with flexibility and miniaturization with the fast development of portable and wearable electronic devices. Herein, flexible aqueous zinc-ion hybrid microsupercapacitors (FAZIHMs) based on Ti3C2Tx anode and MnO2 cathode are constructed, which can successfully operate under 2.0 V voltage window and deliver a high area capacitance up to 252.8 mF/cm2 at 1 mV/s. The Ti3C2Tx//MnO2 FAZIHMs still maintain above 70.8 % capacitance retention with 94.5 % coulombic efficiency after 5000 successive cycles at 11.5 mA/cm2. Furthermore, favorable electrochemical performances are achieved under a series of mechanical bending levels with bending angles ranging from 0° to 90° for the Ti3C2Tx//MnO2 FAZIHMs. A LED and an electronic thermometer can be switched on simultaneously by the two above Ti3C2Tx//MnO2 FAZIHMs in series connection after being fully charged. This study of the FAZIHMs built upon Ti3C2Tx anode and MnO2 cathode with a high area capacitance and a wide operating voltage window aims at opening up a new way to exploit next-generation flexible and miniature electrochemical energy storage devices.