Dissociation mechanism of a C-60-Li+ complex by microscopic hydration: density functional theory study

The hydration structure and electronic state of Li+ doped complexes on the surface of C-60 were investigated by density functional theory calculations. This system is a simple model for the solvation of Li+ at the anode of a lithium-ion battery. C-60 and Li+ bind at approximately 35 kcal mol(-1). The new band of C-60 formed the lowest excited state, 0.1 eV smaller after interaction with Li+. The water molecule preferentially interacted with the Li portion of the C-60-Li+ complex, and a micro-hydration structure was formed around Li+. When four or more water molecules were added to the system, Li+ was removed from the C-60 surface by the water molecules, and a hydration shell was formed around both Li+ and C-60 (separate hydration). The electronic interaction between C-60 and Li+ was completely disrupted by the formation of a microscopic-hydrated shell. Herein, the mechanism is discussed based on the theoretical results.