A synthetic protocol for endohedral fullerene containing lithium (Li@C-60), as well as the synthesis, characterization, and properties of its chemically oxidized derivative [Li+@C-60][PF6-] are reported in full. Simultaneous deposition of Li plasma and C-60 produces a mixture containing Li@C-60 and C-60. Strong intermolecular attraction between Li@C-60 and C-60 has prevented their separation, but this obstacle was surmounted by selective chemical oxidation of Li@C-60, which led to the isolation of a substantial amount of pure [Li+@C-60][PF6-]. For this purpose, an HPLC technique using an electrolyte in the mobile phase was effective in purifying the ionic metallofullerene. [Li+@C-60][PF6-] was stable in air and, compared with [Li+@C-60][SbCl6-], was more stable to moisture and various chemicals. [Li+@C-60][PF6-] holds promise for practical applications. The spectroscopic data (MS, Li-7 and C-13 NMR, UV-vis, and IR) and electrochemical data for [Li+@C-60][PF6-] are disclosed. In addition, the high electron affinity of [Li+@C-60][PF6-] is discussed.