Engineering ultra-enlarged interlayer carbon-containing vanadium disulfide composite for high-performance sodium and potassium ion storage

Abstract

Two-dimension (2D) transition metal disulfides with large interlayer have attracted more and more attention in electrochemical energy-storage systems owing to their excellent electrochemical properties, especially in lithium and sodium ion batteries. Herein, a facile solvothermal method is used to prepare carbon-containing vanadium disulfide, resulting in the ultra-enlarged interlayer spacing of (001) crystal plane from 5.79 Å to 10.2 Å (76.16% expansion), which can provide a wide 2D channel for ions insertion/extraction and a buffer space to alleviate volume change, and shorten ions diffusion distance, thus guaranteeing the rapid electrons transferring. Therefore, when served as an anode in Na+ storage, the ultra-enlarged interlayer carbon-containing vanadium disulfide composite deliverers a high initial discharge specific capacity (570.5 mA h g−1), and still maintains at 477.5 mA h g−1 over 100 cycles at 100 mA g−1. More importantly, it retains a capacity of 286.0 mA h g−1 after 800 cycles at 1000 mA g−1. Besides, for K+ storage, it shows a high initial discharge specific capacity of 543.6 mA h g−1, and 205.2 mA h g−1 is still obtained after cycling 200 cycles at 100 mA g−1. This work opens up one direction to develop smart materials with interlayer-expanded for superior properties batteries anode.