| Summary: | Fullerene-based materials including C<sub>60</sub> and doped C<sub>60</sub> have previously been proposed as anodes for lithium ion batteries. It was also shown earlier that <i>n</i>- and <i>p</i>-doping of small molecules can substantially increase voltages and specific capacities. Here, we study ab initio the attachment of multiple lithium atoms to C<sub>60</sub>, nitrogen-doped C<sub>60</sub> (<i>n</i>-type), and boron doped C<sub>60</sub> (<i>p</i>-type). We relate the observed attachment energies (which determine the voltage) to changes in the electronic structure induced by Li attachment and by doping. We compare results with a GGA (generalized gradient approximation) functional and a hybrid functional and show that while they agree semi-quantitatively with respect to the expected voltages, there are qualitative differences in the electronic structure. We show that, contrary to small molecules, single atom <i>n</i>- and <i>p</i>-doping will not lead to practically useful modulation of the voltage−capacity curve beyond the initial stages of lithiation.
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