Synthesis and Characterization of Lithiated C60 Systems: Applications in Electrochemical Energy Storage

Abstract

Mixed ionic and electronic conduction makes alkali-metal intercalated fullerides a material of interest for solid-state battery applications. Alkali-metal intercalation introduces an electron into the fulleride lattice, allowing alkali-metal ions to occupy the respective octahedral or tetrahedral sites within a monoclinic polymerized structure. The presence of the alkali metal ions within the lattice allows for easy activation of these carbon-based nanomaterial by creating continuous channels for facile ionic conduction, while the presence of the mobile electrons, donated by the alkali metal atoms, also promotes electronic conductivity. A comparison was made between literature analysis of Li4C60 and experimentally synthesized Li3C60. Raman spectroscopy, X-ray diffraction, and Li-NMR were used to characterize the Li3C60 polymeric structure. XRD was used to confirm the crystal structure as a monoclinic polymerized crystal structure. Raman spectroscopy revealed a 6 cm-1 shift in the Ag(2) pentagonal-pinch mode between Li3C60 and pristine C60, compared to a shift of around 25 cm-1 for Li4C60. Li-NMR verified occupation of the octahedral and tetrahedral sites of the C60 lattice. Analysis of lithium intercalated fulleride systems was done to fully characterize and understand materials that have the potential to be safer, and more efficient alternative to current electrolyte technologies.