Structures and properties of carbon-doped silicon as anode material for lithium ions battery: A first-principles study

Anode materials for lithium ions battery have been much less investigated than the cathode materials. Recently, silicon-based anode materials have attracted attentions for its high theoretical capacity. In the present work, the structures and properties of carbon doped silicon as the anode materials of lithium ions battery were investigated by first-principles method. In the doping concentration range from 1.56% to 15.6%, the results show that the stronger Si-C covalent bond leads to a higher bulk modulus of the carbon-doped silicon structures. The band gap of the doped structure decreases with increased doping concentration. The volume expansion can be suppressed by the doping of the carbon atom, and the structures with higher carbon concentrations had a better suppression effect. Meanwhile, the lithium diffusion energy barrier increases with the carbon doping concentration.