Crystal Surface Engineering Induced Active Hexagonal Co2 P-V2 O3 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, Co2 P nanocrystals with high exposure of (211) lattice plane loaded at 2D hexagonal V2 O3 nanosheets (H-Co2 P-V2 O3 ) are designed via the control of morphology. After optimization, this H-Co2 P-V2 O3 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 Co2 P, and the high adsorption and catalysis characteristic of H-Co2 P-V2 O3 for the conversion of LiPSs into LSBs. In the case of modification separator by H-Co2 P-V2 O3 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 14.5mg 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.