Ab initio calculations of polycyclic aromatic hydrocarbons adsorbed on graphite edge for molecular-scale surface coatings of lithium-ion battery anodes

作者：Kawai Takazumi^*

来源：Japanese Journal of Applied Physics, 2014, 53(4): 04EN05.

DOI：10.7567/JJAP.53.04EN05

We have investigated the atomic configurations and electronic structures of graphite edges adsorbed by polycyclic aromatic hydrocarbons, aiming for application to lithium-ion-battery anodes, where thin and robust coating layers are required for fast charge/discharge processes and long lifetime. In particular, we examined the adsorption of a perylene molecule on an edge of graphite. We considered that the edge of perylene connects two layers of graphite with sigma-bonds. We found that the optimized atomic structures are stable and the planar surface of perylene is parallel to the insertion direction of lithium ions similar to the original graphite edges. Therefore, the coating does not disturb the diffusion of lithium ions during charge/discharge processes. Furthermore, there is no hybridization between the graphite edge and the perylene molecule near the Fermi level, even though they have chemical bonds between them. Thus, the electronic states of the chemisorbed perylene molecule are insensitive to the change in the electric potential of the graphite. Consequently, we expect them to suppress the electrochemical decomposition of electrolytes and solvents on the anode surface. Hence, polycyclic aromatic hydrocarbons are one of the best candidates for the coating materials of graphite anodes for realizing a higher charge/discharge rate and longer lifetime.

• 出版日期2014-4