Electrochemical and Pseudocapacitive Analysis of Rod-Like MoO2@MoSe2@NC Heterostructures for High-Performance Lithium Ion Batteries

Abstract

A micro-scale rod-like heterostructure derived from molybdenum-based metal organic framework (Mo-MOF) has been successfully prepared via subsequent annealing treatment, which assembled from N-doped carbon encapsulated MoSe 2 nanosheets grown on the surface of MoO 2 microrod (named as MoO 2 @MoSe 2 @NC). For this novel heterostructure, the MoO 2 nanoparticles assembled into rod core not only serve as supporting substrate for facilitating the fast kinetics of Li + cations inside the electrode but also protect the MoSe 2 structure from restacking in the charge/discharge process. Moreover, the outer-layered MoSe 2 nanosheets enable the fast lithium ion movement owing to its large interlayer spacing. Moreover, this unique rod-like core–shell structure composite could further effectively alleviate the structural strains caused by large volume expansion during charge/discharge process, thus leading to stable electrochemical performance when evaluated as anode material for lithium ion batteries. Electrochemical testing exhibits that the MoO 2 @MoSe 2 @NC heterostructure presents highly reversible capacity of 468 mAh g −1 at 0.5 A g −1 and superior rate capability (318 mAh g −1 even at 5.0 A g −1 ), which is attributed to the synergistic effect of N-doped carbon encapsulated MoSe 2 nanosheets and MoO 2 nanoparticles.