Application of T-4,T-4,T-4-graphyne for anode of Na-ion battery: first principle theoretical study

The sodium (Na) storage behaviour of T-4,T-4,T-4-graphyne of two-dimensional porous carbon sheet is explored using the density functional theory (DFT). The energy of adsorption and barrier, storage capacity, and open-circuit voltage are calculated. The calculations predict that Na atom is extraordinary mobile on T-4,T-4,T-4-graphyne monolayer as a result of the relatively slight energy barrier. The Na storage capacity is as high as Na8C9, which exceeds the values reported for graphite and some other two-dimensional carbon-based materials. The high Na mobility and theoretical capacity make T-4,T-4,T-4-graphyne monolayer suitable for implementation in rechargeable ion batteries. The electronic properties are also studied to ensure that T-4,T-4,T-4-graphyne is suitable for Na-ion batteries as an anode material, and they revealed that semiconductor-metal transition is induced by Na adsorption. The favourable electronic conduction is another demand for promising Na-ion batteries. These results predict that the application of T-4,T-4,T-4-graphyne sheet will increase efficiency of the Na-ion batteries.