Enhanced electron mobility and interfacial stability in Pt-doped graphene composite electrode for liquid metal applications

Gallium-based liquid metals are gaining significant attention due to their superior thermal and electrical conductivity, high surface tension, and excellent biocompatibility. However, the formation of interfacial compounds reduces electron mobility and destabilizes the interface, ultimately limiting their performance. This study addresses these issues by incorporating graphene (Gr) reinforcement to prevent interfacial compound formation and introducing atomic-level platinum (Pt) doping through an impregnation-reduction method, resulting in the development of a Cu-Gr@Pt composite electrode. The composite electrode was characterized using high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS). To assess electrical performance, atomic force microscopy (AFM) was employed to measure electrode conductivity and solid-liquid interface contact. Density functional theory (DFT) calculations demonstrate that Pt doping significantly enhances electron mobility in graphene-based materials and improves solid-liquid interfacial interactions through hybridization between Ga's p orbitals and Pt's d orbitals. Electrical measurements reveal that Pt doping lowers the bulk resistance of the electrode from 35.17 μΩ to 30.33 μΩ, while the solid-liquid contact resistance decreases from 85.50 μΩ to 50.50 μΩ in comparison to the Cu electrode. This work provides valuable insights into the design of advanced composite electrodes, offering a practical approach to enhancing the performance of gallium-based liquid metals for future electronic and energy storage applications.