Strongly coupled C@MoSe2@OMWCNT heterostructure as an anode for sodium-ion batteries

Abstract

MoSe2, with its extraordinary theoretical capacity, has emerged as a profoundly auspicious anode material for Sodium-ion Batteries (SIBs). However, the actual realization of SIBs encounters hurdles arising from insufficient electron and ion transportation capabilities, along with the irreversible transformation of Mo/Na2Se into MoSe2, eventually substituted by Mo/Se. In this investigation, By employing Mo-based complexes, we have achieved a triumphant synthesis of C@MoSe2@OMWCNT (oxidized multiwall carbon nanotubes) materials, wherein OMWCNTs serve as the fundamental substrate. Theoretical analysis has revealed that the utilization of OMWCNTs not only enhances the structural stability of the anode materials but also improves the electrical conductivity and Na+ ion mobility (the Na+ diffusion barrier: (MoSe2) 0.91 eV vs (C@MoSe2@OMWCNT) 0.41 eV) of the C@MoSe2@OMWCNT. These properties make C@MoSe2@OMWCNT a promising candidate for the development of high-performance SIBs. Furthermore, the Ex-situ Transmission Electron Microscopy (TEM) examination, unveils the emergence of Se and MoSe2 within the C@MoSe2@OMWCNT. The findings indicate that the outer carbon coating layer efficiently prevents contact between Se and the electrolyte, thereby impeding the formation of polyselenides. When C@MoSe2@OMWCNT is employed as the anode for the SIB, it exhibits exceptional cycle stability, with a capacity of 303 mA h g−1 and 189 mA h g−1 after 500 and 3000 cycles, respectively, under a current density of 5 A g−1. Overall, this investigation provides valuable insights into the design and synthesis of advanced anode materials for SIBs, which could have significant implications for the development of next-generation energy storage devices.