Phase evolution of VC-VO heterogeneous particles to facilitate sulfur species conversion in Li-S batteries

Lithium-sulfur (Li-S) batteries with ultrahigh theoretical energy densities have thus far attracted significant attention as the next-generation energy storage systems. However, the presence of the polysulfide shuttle effect and sluggish reaction kinetics have critically hindered their research progress. Herein, the fabrication of novel VC-VO heterogeneous particles supported on a hierarchical porous carbon matrix (VC-VO/HPC) is reported that regulate the disordered motion of lithium polysulfides (LiPSs); these particles can simultaneously achieve powerful anchoring, fast diffusion, and high-efficiency conversion of LiPSs. Moreover, the in situ characterization of VC-VO/HPC@S provides a rational inference for their phase evolution in the galvanostatic charge/discharge process. The formation of the V${}_5$S${}_8$ phase during electrochemical cycling primarily facilitates the interconversion of liquid-phase polysulfides. Consequently, the VC-VO/HPC@S cathodes exhibit excellent capacity performance (1484 mAh g${}^{-1}$ at 0.1 C) and ultrahigh cycle stability (0.045% decay rate per cycle at 5 C). The pouch cell exhibits a high energy density of 358 Wh kg${}^{-1}$. This approach explores the phase evolution of VC-VO particles in an electrochemical environment and is valuable for the development of Li-S batteries with high area capacity and long cycle life. (© 2022 Wiley‐VCH GmbH)