Rational design of a C 3 N/C 3 B 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 C 3 N/C 3 B p-n heterostructure was systematically investigated by first-principles calculations. The bonding strength of Li in C 3 N is relatively low (-0.53 eV), whereas the C 3 N/C 3 B 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 C 3 N/C 3 B heterostructure are mainly caused by the synergy effect and internal electric field of the p-n heterostructure. Moreover, the electronic structures indicate that the C 3 N/C 3 B heterostructure has good conductivity with a tiny bandgap of 0.09 eV. Compared to pristine C 3 N, the stiffness of the C 3 N/C 3 B heterostructure improved significantly (549.35 N m -1 ). Besides, the C 3 N/C 3 B 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 C 3 N/C 3 B heterostructure is a prospective anode material for lithium-ion batteries.