Flexible and High‐Performance MXene/MnO2 Film Electrodes Fabricated by Inkjet Printing: Toward a New Generation Supercapacitive Application

Abstract With the deepening of the commercialization of flexible electronic products, it is urgently needed to develop a handleable solution for the applications of printing high‐performance and wearable energy storage devices. Herein, flexible, low‐cost, and high‐performance MXene/manganese dioxide (MnO 2 ) composite film electrodes are reported to meet this urgent expectation. The MXene‐based composite film electrodes with different MnO 2 content are prepared by inkjet printing using MXene/MnO 2 ink. Characterization and test results show that there is a synergistic effect between MXene and MnO 2 , which can effectively achieve faster electron transfer and shorter diffusion path, thus improving the overall electrochemical performance of the composite. The inkjet‐printed MXene/10 wt% MnO 2 composite film electrode, with an excellent conductivity of 3400 S m −1 , exhibits an ultrahigh volumetric capacitance of 312 F cm −3 and retains 130.8% of the initial capacitance after 5000 charge/discharge cycles. Moreover, the fabricated flexible symmetrical supercapacitor shows a superior areal energy density of 0.51 μWh cm −2 at a power density of 12.5 μW cm −2 . Taken together, inkjet printing technology provides a low‐cost, large‐area manufacturing route for different MXene‐based composites, which are expected to promote the development of novel energy storage technologies that exploit the attractions of MXene.