2D porous Nb4N5@Nb2C heterojunctions for high-performance Li-ion batteries

Abstract

Constructing transition metal nitrides (TMNs) with a 2D porous structure is an effective strategy to alleviate their volume expansion and self-aggregation issues, eventually enhancing their electrochemical performance. However, very few studies have been reported up to now. Herein, 2D porous Nb4N5@Nb2C heterojunctions are successfully synthesized from Nb2C MXene precursor by employing a two-step nitridation method in NH3 atmosphere. Owing to the abundant active sites, fast Li-ions diffusion paths, and sufficient buffer space for releasing volume expansion, 2D porous Nb4N5@Nb2C heterojunctions achieve high rate performance and excellent cycling stability, maintaining 109.2 mAh g−1 at 2 A g−1 after 800 cycles. This work provides a facile strategy for building 2D porous TMNs and their heterojunctions with excellent electrochemical performances.