Reversible lithium storage capacity on carbon nitride by electric field.

Graphitic carbon nitride (g-C 3 N 4) has attracted enormous interest because of its prominent photocatalytic performance. Due to the planar π conjugation structure which should provide good binding energy for adsorption of metal atoms including lithium (Li) and sodium (Na), g-C 3 N 4 also possesses great application potential in ion batteries. Here, first-principles calculations are performed to investigate its application in lithium ion batteries (LIBs), focusing on the electric field effect on the Li storage. Our results revealed that Li adsorbed C 3 N 4 (Li–C 3 N 4) exhibits good modulation of its Li binding energy by applying external vertical electric field. The Bader charge analysis and charge density difference calculations provide a deep insight into the tunable Li adsorption to C 3 N 4 sheets. Our theoretical results suggest that C 3 N 4 is a suitable anode material for LIBs. • The physical mechanism concerning the good Li storage is unraveled.. • Strong ionic bonding between Li and C3N4 layer is demonstrated by charge density difference and Bader charge analysis. • Both the average charge and binding energies of Li exhibit good modulation by external electric field. • Non-monotonous variation of the binding energy of Li with electric field is revealed. [ABSTRACT FROM AUTHOR]