Construction of N-doped multichannel carbon nanofibers embedded with amorphous VS4 nanoparticles for potassium-ion batteries with ultralong-term cycling stability

Abstract

Due to the low cost of potassium and its low redox potential, potassium ion batteries (KIBs) have been touted as viable candidates for large-scale energy storage devices. However, practical application of KIBs remains challenging due to a lack of suitable electrode materials capable of effectively storing large-sized K ions. The present article describes the successful preparation of a highly stable one-dimensional VS4/carbon composite comprising VS4 nanoparticles confined within N-doped multichannel carbon nanofibers (VS@NMCNF), using an electrospinning method followed by in-situ pyrolysis sulfidation, for use in KIBs. The porous structure of the carbon nanofiber is critical in allowing vanadium sulfide to have an amorphous crystal structure. Benefiting from the fast ion/electron transport, the amorphous nature of vanadium sulfide, and the structural robustness of the carbon matrix, the VS@NMCNF electrode exhibits a high reversible capacity (∼404.6 mAhg−1 at 0.5 A g−1), superior cycling stability for 4000 cycles, and an excellent rate capability (284.8 mAhg−1 at 2.0 A g−1). Additionally, the K-ion full cell composed of VS@NMCNF//Prussian blue demonstrates stable reversible capacity (233.1 mAhg−1 at 0.1 A g−1) and a high-rate capability (187.9 mAhg−1 at 2.0 A g−1).