An Ultrahigh Energy Density Flexible Asymmetric Microsupercapacitor Based on Ti3C2Tx and PPy/MnO2 with Wide Voltage Window

Ti3C2Tx MXene, as a new 2D material, with unique physical and chemical properties, is ideal for building high performance miniaturized electrochemical energy storage devices. However, the operating voltage window of Ti3C2Tx based microsupercapacitor (MSC) in symmetric structure is very narrow (≤0.6 V), which affects its practical application. Herein, a flexible asymmetric microsupercapacitor (AMSC) based on Ti3C2Tx//polypyrrole (PPy)/MnO2 is reported, where Ti3C2Tx is deposited on graphite paper (GP) by electrophoresis method as negative electrodes, MnO2 and PPy are electrochemically deposited on GP successively as positive electrodes, and polyvinyl alcohol/sulfuric acid (PVA/H2SO4) as the quasi‐solid electrolyte. This AMSC based on Ti3C2Tx//PPy/MnO2 operates at 1.2 V voltage window, which is two times wider than symmetric Ti3C2Tx based MSC. And its maximum areal capacitance and areal energy density can reach up to 61.5 mF cm−2 and 6.73 µWh cm−2 respectively. Moreover, three above AMSCs in series connection can turn on three lights after being charged. And the AMSC also shows high flexibility under mechanical bending level (bending angle with 0°–180°). The flexible AMSC based on Ti3C2Tx//PPy/MnO2 with ultrahigh energy density is a promising candidate for exploiting and fabricating next‐generation miniature integrated energy storage devices. A flexible asymmetric microsupercapacitor (AMSC) based on Ti3C2Tx and PPy/MnO2 is reported by electrodeposition methods onto graphite paper substrates. The AMSC can operate in an extended 1.2 V voltage window, which is twice than that of Ti3C2Tx based symmetric microsupercapacitor. In addition, it also exhibits remarkable flexibility, high area capacitance of 61.5 mF cm−2, well energy density and excellent stability.