Triboelectric Series of Two-dimensional Metal Carbide MXenes

The ever-increasing prevalence of intelligent electronics underscores an escalating demand for sustainable power sources. Among the emerging energy harvesting technologies, triboelectric nanogenerators (TENGs) stand out as a promising solution for such pressing needs. To date, ongoing efforts have primarily focused on enhancing TENG output, particularly through the development of novel triboelectric materials. Among the potential candidates is the thriving class of two-dimensional transition-metal carbides, MXenes, which have predominantly been incorporated into triboelectric layers as nanofillers to enhance their triboelectric properties. Yet, the specific triboelectric characteristics of distinct MXenes remain marginally explored. Herein, the triboelectric properties of various metal carbide MXenes, i.e., V₂CT_x, Ti₃C₂T_x, and Nb₂CT_x, are investigated by assessing the performance of various MXene-based TENGs combined with different polymers and analyzing their surface potential. According to the attained triboelectric polarities, a triboelectric series of the studied MXenes is determined, demonstrating their remarkable positive triboelectric properties. Further investigations preliminarily reveal the influence of the synthesis method, etchants, intercalating compounds, and postsynthesis procedures on the triboelectric properties of MXenes. Hence, beyond extending the conventional triboelectric series to different metal carbide MXenes, the findings present innovative perspectives on leveraging MXenes to develop high-performance TENGs for flexible and wearable electronics.