Rational design of a C3N/C3B p–n heterostructure as a promising anode material in Li-ion batteries

It is urgent to develop high-performance anode materials for lithium-ion batteries. In this work, a C₃N/C₃B p-n heterostructure was systematically investigated by first-principles calculations. The bonding strength of Li in C₃N is relatively low (-0.53 eV), whereas the C₃N/C₃B heterostructure (-1.64 eV to -2.84 eV) can greatly improve the bonding strength without compromising the Li migration capability. The good bonding strength and Li mobility in the C₃N/C₃B heterostructure are mainly caused by the synergy effect and internal electric field of the p-n heterostructure. Moreover, the electronic structures indicate that the C₃N/C₃B heterostructure has good conductivity with a tiny bandgap of 0.09 eV. Compared to pristine C₃N, the stiffness of the C₃N/C₃B heterostructure improved significantly (549.35 N m^-1). Besides, the C₃N/C₃B heterostructure presents a high lithium-ion storage capacity (986.61 mA h g^-1). The ultrahigh stiffness, good conductivities of electrons and ions, high bonding strength of Li, and high capacity show that the C₃N/C₃B heterostructure is a prospective anode material for lithium-ion batteries.