Lithium Attachment to C60 and Nitrogen- and Boron-Doped C60: A Mechanistic Study

• Main Authors: Yingqian Chen, Chae-Ryong Cho, Sergei Manzhos
• Format: Article
• Language: English
• Published: MDPI AG 2019-07-01
• Series: Materials
• Subjects: Li ion battery; fullerene; doping; density functional theory
• Online Access: https://www.mdpi.com/1996-1944/12/13/2136

Fullerene-based materials including C₆₀ and doped C₆₀ 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 C₆₀, nitrogen-doped C₆₀ (<i>n</i>-type), and boron doped C₆₀ (<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&#8722;capacity curve beyond the initial stages of lithiation.