Fabrication of single-hole hollow MoSe2@NC/CNT microsphere via a salt-assisted spray drying for high-performance potassium-ion batteries

초록

This study proposes a facile salt-templated approach for fabricating single-hole hollow microspheres (MoSe2@NC/CNT) comprising MoSe2, an N-doped carbon (NC) matrix, and a carbon nanotube (CNT) backbone as anode materials in potassium-ion batteries (KIBs). These microspheres feature a well-defined hollow structure with a single aperture and comprise uniform few-layered MoSe2 nanocrystals embedded within a carbonaceous matrix consisting of CNT and NC. The synthesis involves one-pot spray drying using NaCl as a recyclable hard template, which is novel in that it allows for easy formation of porous structures without the use of expensive and difficult to fabricate nano-sized hard templates such as SiO2 and latex beads for making pores. The carbon matrices effectively not only preserve the microsphere architecture during NaCl removal but also prevent MoSe2 restacking and overgrowth. This well-engineered composite offers multiple conductive pathways, facilitating ion and electron transport while minimizing K+ diffusion distances. Furthermore, the porous CNT/carbon matrix mitigates significant volume changes during cycling, reinforcing the structural integrity. Thus, the MoSe2@NC/CNT microsphere demonstrates outstanding electrochemical performance, exhibiting a high specific capacity and enduring cycling stability (277/207 mA h g−1 after 1000 cycles at 0.5 and 2.0 A∙g−1), along with remarkable rate capability. Hence, it is a promising anode material for KIBs.

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