Two-dimensional transition metal carbide nitrides (MXenes) have been extensively explored in diverse areas, such as electrochemical energy storage and flexible electronics. Although the solution-processed MXene-based device has made significant achievements, it is still a challenge to develop large-scale and high-resolution printing methods for flexible printed electronics. In this work, we reported a novel strategy of a porous interlocking structure to obtain flexible MXene/laser-induced graphene (LMX) composite electrodes with enhanced adhesion and high printing resolution. In comparison to traditional printed MXene electrodes, the LMX electrode with an interlocking interface possesses enhanced mechanical properties (adhesive strength of 2.17 MPa) and comparable electrical properties (0.68 S/mm). Furthermore, owing to the outstanding stability and flexibility, the LMX-based triboelectric nanogenerator (TENG) can be used as a self-powered sensor to monitor finger-bending movement. A support vector machine (SVM)-assisted self-powered motion sensor can distinguish the bending angle with high recognition accuracy and can effectively identify different angles. The successful experience of directly printing flexible electrodes with excellent mechanical and electrical properties can be promoted to other solution-processed two-dimensional materials. Our strategy opens up a promising perspective to develop flexible and printed electronics.
Keywords: MXene; interface engineering; laser-induced graphene; machine learning; triboelectric nanogenerator.