The optimal initial configuration of silicon-functionalized graphene for lithium-ion battery anode

Abstract

Silicon-functionalized graphene in its initial configuration, as anode materials for lithium-ion battery, will directly affect the battery’s reversible capacity, charge and discharge rate and service life. To present its optimal initial configuration, the relaxation and stretching properties of silicon-functionalized graphene were studied using molecular dynamics simulation with the Tersoff potential, the Lennard–Jones potential and the velocity Verlet time-stepping algorithm. In this study, many models of silicon-functionalized graphene with different arrangement of silicon atoms, different Si/C ratios, different vacancy defect ratios, different tension rates and different temperatures were primarily developed respectively to simulate the influence of different configurations on the volume, potential energy, elastic modulus, tensile strain, strength and other properties of the model, and we found that (1) the model with random arrangement of silicon atoms possessed biggest system potential energy, biggest volume and highest mechanics property among all models. (2) With the increasing amount of silicon atoms, the wavy corrugations and the peak became clearer, the potential energy decreased and volume increased. The model with Si/C ratio of 3.28% possessed highest mechanics property. (3) With the increasing vacancy, the system’s potential energy increased and volume decreased. The model with a vacancy defect ratio of 1% possessed highest mechanics property parameters. (4) Mechanics properties were the highest at the temperature of 300 K.