Phase Evolution of VC‐VO Heterogeneous Particles to Facilitate Sulfur Species Conversion in Li−S Batteries

• Published in: Advanced functional materials 2023-01, Vol.33 (3), p.n/a
• Main Authors: Dong, Xinji, Liu, Xiaozhang, Shen, Pei Kang, Zhu, Jinliang
• Format: Article
• Language: English
• Subjects: Conversion; Decay rate; Diffusion rate; Energy storage; Evolution; heterostructures; in situ characterization; Lithium; Lithium sulfur batteries; Materials science; phase evolution; polysulfide regulation; Polysulfides; Porous media; Reaction kinetics; Storage systems
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202210987

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 V5S8 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. A unique VC‐VO heterogeneous particles based on a hierarchical porous carbon matrix are successfully prepared to facilitate sulfur‐related species conversion in Li−S batteries. The electrochemical phase evolution of VC‐VO during the cycling is revealed in polysulfide‐rich conditions. Additionally, it is explored how the formation phase (V5S8) defines the polysulfide.