Centrifugal-Gravity-Enforced Deposition of MXene Electrodes for High-Performance and Ultrastable Microsupercapacitors.

ABSTRACT

Two-dimensional (2D) transition metal carbides, known as MXenes, have captured much attention for their excellent electrical conductivity and electrochemical capability. However, the susceptibility of MXenes to oxidation, particularly Ti3C2Tx transforming into titanium dioxide upon exposure to ambient air, hinders their utilization for extended operational life cycles. This work introduces a simple and straightforward method for producing ultrathin MXene electrode films tailored for energy storage applications, employing centrifugal-gravity force. Our approach significantly suppresses the oxidation phenomenon that arises in MXene materials and also effectively prevents the recrystallization of potentially residual LiF during the film formation. Additionally, the utilization of this MXene electrode in an all-solid-state microsupercapacitor (MSC) with an interdigitated pattern demonstrates an exceptionally improved and stable electrochemical performance. This includes a high volumetric capacitance of approximately 467 F cm-3, an energy density of around 65 mWh cm-3, and impressive long-term cycle stability, retaining about 94% capacity after 10 000 cycles. Moreover, a downsized MSC device exhibits remarkable mechanical durability, retaining over 98% capacity even when folded and sustaining stability over extended periods. Therefore, we believe that this study provides valuable insights for advancing highly integrated energy storage devices, ensuring exceptional electrochemical efficiency and prolonged functionality in diverse environments, whether ambient or humid.