Superior pseudocapacitive performance and mechanism of self-assembled MnO2/MXene films as positive electrodes for flexible supercapacitors

•A MnO2/Ti3C2Tx hybrid cathode with a 1D–2D staggered structure is prepared.•Hybrid cathode exhibits prominent electrochemical stability for anodic oxidation.•The fabricated quasi-solid-state supercapacitor delivers a high-voltage window of 1.9 V.•The supercapacitor shows high energy and power densities with flexibility.