Electrochemical properties of lithium metal doped C₆₀ fullerene for battery applications

The development of anode materials with an optimum cell voltage and better stability is an important challenge for high-performance Li-ion batteries. In this study, we have investigated the electrochemical potential of pristine and Li-doped C₆₀ fullerene through density functional theory (DFT) simulations, with a focus on their potential applications in lithium-ion batteries. Our findings reveal that exohedral doping with a more electronegative counter anion can significantly increase the cell voltage. Particularly, when lithium cations are encapsulated within C₆₀ fullerene with antimony hexachloride (SbC l₆⁻) as the counter anion, the highest cell voltage of 2.06 V is achieved. Furthermore, we have explored the impact of substituting carbon atoms with boron, nitrogen, phosphorus, and silicon on the Gibbs free energy change and cell potential. These substitutions led to an acceptable cell voltage compared to pristine C₆₀ fullerenes where the most suitable cell voltage of 1.75 V is observed for SbCl₆/Li@C₅₉B. This enhancement occurs because boron increases the electron deficiency of C₆₀ fullerene, thereby promoting stronger interactions with electronegative counter anions. These systems with a cell voltage of 1.75 V are deemed ideal candidates in lithium-ion batteries.