Coordination of Mg2+ with Chitosan for Enhanced Triboelectric Performance

In this work, Mg²⁺ modified chitosan (Mg²⁺/CS) is proposed and successfully designed. By investigating the effects of the Mg²⁺ and CS interaction on hydrogen bonding, dipoles, charge density, surface potential, and roughness, the coordination between Mg²⁺ and CS is verified and the mechanism of coordination improving tribological properties is elucidated. The Mg²⁺/CS coordination structure enhances intermolecular interactions, promoting the formation of new hydrogen bonds and increasing the dipoles. Compared to CS, the relative dielectric constant of Mg²⁺/CS increased by 76%, the surface potential increased by 70 mV, and the root mean square roughness increased by 39.4 nm. The open-circuit voltage, short-circuit current, and charge density of the triboelectric nanogenerator (TENG) fabricated from Mg²⁺/CS were increased by 100%, 94%, and 75%, respectively, compared to the CS-TENG fabricated from pure CS. The coordination of Mg²⁺ increased the charge density of the Mg²⁺/CS-TENG, significantly enhancing its charge transfer capability. The Mg²⁺/CS-TENG successfully provided power for photodetectors and LEDs. Mg²⁺/CS exhibited excellent flexibility and skin adhesion, and the Mg²⁺/CS-TENG successfully converted the mechanical energy generated by human joint motion into electrical signals. The coordination structure of Mg²⁺ with CS enhances the triboelectric performance of Mg²⁺/CS-TENG, providing new light for the research of chitosan-based TENGs.