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

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.

Automated summary

Purposefully controlling the exposure of crystal planes can improve the catalytic activity of nanocrystals. In this study, Co2P nanocrystals with high exposure of the (211) lattice plane were designed and loaded onto 2D hexagonal V2O3 nanosheets. This material showed enhanced redox kinetics and superior performance in lithium-sulfur batteries.