Catalytic FeP decorated carbon black as a multifunctional conducting additive for high-performance lithium-sulfur batteries

Sulfur hosts with high sulfur affinities and catalytic activities are widely studied for lithium-sulfur batteries to tackle polysulfide shuttling and the sluggish sulfur redox kinetics. Although conducting additives (typically carbon black) are essential components in slurry-coated cathodes, their modification received much less attentions as an alternative solution to the above-mentioned issues. Herein, we demonstrate that introducing catalytic materials to the conventional conducting additive of carbon black acts as a feasible strategy to improve battery performance. Super P carbon black decorated with FeP nanoparticles (SP/FeP) is synthesized using a scalable method and served as the conducting additive in sulfur cathodes constructed from common carbon hosts, namely carbon nanotubes and nanofibers. At a low addition of SP/FeP of 10 wt% (the conventional 8:1:1 recipe), SP/FeP exhibits strong sulfur immobilizations and effective electrocatalysis for the liquid-liquid and liquid-solid transitions. High specific capacities (1518 mAh g(-1) at 0.2 C), excellent rating performance (728 mAh g(-1) at 5 C) and stable longterm cycling are achieved. Pouch cells with a 7.0 mg cm(-2) sulfur loading are also demonstrated to present high areal capacities and charge/discharge stabilities. Electrochemical measurements and density functional theory calculations were performed to reveal the working mechanism of the SP/FeP conducting additive. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

This study demonstrates that introducing catalytic materials to the conventional conducting additive carbon black can improve battery performance. The use of FeP nanoparticles decorated Super P carbon black (SP/FeP) as the conducting additive in sulfur cathodes resulted in high specific capacities, excellent rating performance, and stable longterm cycling.