Crystal Surface Engineering Induced Active Hexagonal Co₂P‐V₂O₃ for Highly Stable Lithium–Sulfur Batteries

Abstract

Purposeful control of the highly active crystal planes is an effective strategy to improve the nanocrystalline catalytic activity. Therefore, Co2P nanocrystals with high exposure of (211) lattice plane loaded at 2D hexagonal V2O3 nanosheets (H‐Co2P‐V2O3) are designed via the control of morphology. After optimization, this H‐Co2P‐V2O3 boosts the redox kinetics of lithium polysulfides (LiPSs) in lithium–sulfur batteries (LSBs), which is due to the increase of the Co‐active sites by exposing more (211) lattice planes of Co2P, and the high adsorption and catalysis characteristic of H‐Co2P‐V2O3 for the conversion of LiPSs into LSBs. In the case of modification separator by H‐Co2P‐V2O3 composite, the battery achieves an outstanding reversibility of 876.9 mAh g−1 over 500 cycles at 1 C, a superior rate property of 611.5 mAh g−1 at 8 C, and a long‐term cycling performance with a low attenuation of 0.04% per cycle over 1000 cycles at 4 C for LSBs. Impressively, a remarkable areal capacity of 12.38 mAh cm−2 is retained under the high sulfur loading of 14.5 mg cm−2 after 100 cycles. It is believed that the crystal surface engineering provides guidance to further improve the electrochemical performance of the LSB field.

In Situ Non‐Topotactic Reconstruction‐Induced Synergistic Active Centers for Polysulfide Cascade Catalysis

“…[17] According to the molecular orbital theory, electron transfer from the d orbital of SCTMC to the LUMO of polysulfides is essential for triggering polysulfide reduction. [18,19] However, the diverse LUMO positions of different polysulfides signify discrepant energy-level differences with the specific dband center of SCTMC. In this scenario, the smaller the energy-level difference (∆), the more favorable the interfacial electron transfer, and thus the easier the corresponding polysulfide reduction.…”

Field‐assisted electrocatalysts spark sulfur redox kinetics: From fundamentals to applications

“…If the VB of the electrocatalysts is lower than the LUMO of LiPSs, the driving force stemming from the external circuit stimulates nonspontaneous electron transport from electrocatalysts to LiPSs, which directly correlates with the polarization potential. [ 132 ] Specifically, the smaller energy‐level difference between the LUMO of LiPSs and the VB of electrocatalysts determines the lower polarization potential that needs to be overcome, thus correlating the smaller Gibbs free energy. According to the Bulter‐Volmer equation, enhanced charge transfer kinetics are acquired.…”