The catalytic role of surface Co(PO3)2 on CoP for high-performance lithium-sulfur batteries

Abstract

Electrocatalysts is maturely explored to strengthen the conversion kinetics for lithium polysulfides (LiPSs) and avoid the shuttle effect. However, the perspicuous role of surface oxidation species electrocatalysts on LiPSs conversion kinetics is still confused and needs to be uncovered. Here, we prepared progressively surface oxidized CoP/CNT (OCoP/CNT) and confirmed the formation of surface amorphous Co(PO3)2. The generation of surface Co(PO3)2 induces the phosphorous vacancy synergistically improving the catalytic conversion kinetics of OCoP/CNT functionalized separator towards LiPSs. Furthermore, the In-situ Raman spectra is adopted to disclose the key catalytic role of Co(PO3) on OCoP/CNT. With an E/S ratio of 15 µL mg−1, the lithium sulfur (Li-S) battery with OCoP/CNT functionalized separator showcases amazing and satisfying high-rate performance, especially at 2C and 3C. This study would get across the full comprehension of the catalytic role of the surface oxidation species and guide the new approach for the metal-based electrocatalyst of Li-S battery.