Conformal carbon nitride thin film inter-active interphase heterojunction with sustainable carbon enhancing sodium storage performance.

Sustainable, high-performance carbonaceous anode materials are highly required to bring sodium-ion batteries to a more competitive level. Here, we exploit our expertise to control the deposition of a nm-sized conformal coating of carbon nitride with tunable thickness to improve the electrochemical performance of anode material derived from sodium lignosulfonate. In this way, we significantly enhanced the electrochemical performances of the electrode, such as the first cycle efficiency, rate-capability, and specific capacity. In particular, with a 10 nm homogeneous carbon nitride coating, the specific capacity is extended by more than 30% with respect to the bare carbon material with an extended plateau capacity, which we attribute to a heterojunction effect at the materials' interface. Eventually, the design of (inter)active electrochemical interfaces will be a key step to improve the performance of carbonaceous anodes with a negligible increase in the material weight.