Decoration of carbon encapsulated nitrogen-rich MoxN with few-layered MoSe2 nanosheets for high-performance sodium-ion storage

Abstract

Transition metal nitrides have become the focus of research in sodium ion batteries (SIBs) due to their unique metal properties and high theoretical capacity. However, the low actual capacity is still the main bottleneck for their application. Herein, using Mo-aniline frameworks as precursors, the carbon encapsulated nitrogen-rich MoxN is decorated by few-layered MoSe2 nanosheets (MoSe2@MoxN/C-I) after the facile calcinating, selenizing, and nitriding. The carbon encapsulation can effectively strengthen the structural stability of MoxN. The nitrogen-rich MoxN and decoration of few-layered MoSe2 can create rich heterointerfaces and extra active sites for rapid sodium-ion storage, thus promoting reaction kinetics and improving actual capacity. The MoSe2@MoxN/C-I as an anode achieves a large reversible capacity of 522.8 mAh g−1 at 0.1 A g−1, and 254.3 mAh g−1 capacity is obtained after 6000 cycles at 5.0 A g−1, showing signally improved sodium-ion storage properties. The storage mechanisms and kinetic behaviors are described systematically via the advanced testing techniques and density functional theory (DFT) calculations. It is found that the nitrogen-rich MoxN as the substrate is the basis of long cycling stability, and the few-layered MoSe2 are the key to improving actual capacity. This work indicates that the decoration of few-layered selenides has a broad application prospect in high-performance metal-ion batteries.