Co4N-Decorated 3D Wood-Derived Carbon Host Enables Enhanced Cathodic Electrocatalysis and Homogeneous Lithium Deposition for Lithium-Sulfur Full Cells

The sluggish kinetics of sulfur conversion in the cathode and the nonuniform deposition of lithium metal at the anode result in severe capacity decay and poor cycle life for lithium-sulfur (Li-S) batteries. Resolving these deficiencies is the most direct route toward achieving practical cells of this chemistry. Herein, a vertically aligned wood-derived carbon plate decorated with Co4N nanoparticles host (Co4N/WCP) is proposed that can serve as a host for both the sulfur cathode and the metallic lithium anode. This Co4N/WCP electrode host drastically enhances the reaction kinetics in the sulfur cathode and homogenizes the electric field at the anode for the uniform lithium plating. Density functional theory calculations confirm the experimental observations that Co4N/WCP provides a lower energy barrier for the polysulfide redox reaction in the cathode and a low adsorption energy for lithium deposition at the anode. Employing the Co4N/WCP host at both electrodes in a S@Co4N/WCP||Li@Co4N/WCP full cell delivers a specific capacity of 807.9 mAh g(-1) after 500 cycles at a 1 C rate. Additional experiments are performed with high areal sulfur loading of 4 mg cm(-2) to demonstrate the viability of this strategy for producing practical Li-S cells.

Automated summary

The study proposes a vertically aligned wood-derived carbon plate decorated with Co4N nanoparticles host as a host for both the sulfur cathode and metallic lithium anode, significantly enhancing reaction kinetics in the sulfur cathode and homogenizing the electric field at the anode for uniform lithium plating; experimental results confirm that Co4N/WCP on both electrodes can greatly improve the cycling performance and capacity of the battery.