Implanting Single Zn Atoms Coupled with Metallic Co Nanoparticles into Porous Carbon Nanosheets Grafted with Carbon Nanotubes for High-Performance Lithium-Sulfur Batteries

The electrochemical performance of lithium-sulfur (Li-S) batteries is severely hindered by the sluggish sulfur redox kinetics and the shuttle effect of lithium polysulfides (LiPSs). Herein, an integrated composite catalyst consisting of Co nanoparticles and single-atom (SA) Zn co-implanted in nitrogen-doped porous carbon nanosheets grafted with carbon nanotubes (Co/SA-Zn@N-C/CNTs) is rationally developed toward this challenge. Experimental and theoretical investigations indicate that the synergistically dual active sites of Co and atomic Zn-N-4 moieties with an optimal charge redistribution not only strongly confine the LiPSs but also effectively catalyze its conversion reactions by lowering the energy barrier from Li2S2 to Li2S while the N-doped porous carbon-grafted CNTs enables a large surface area for more active site exposure and provides a fast electron/ion pathway. Benefiting from synergies, Li-S batteries equipped with the Co/SA-Zn@N-C/CNTs-based sulfur cathode exhibit a high reversible capacity of 1302 mAh g(-1) at 0.2 C and a low capacity fading rate of 0.033% per cycle over 800 cycles at 1 C. Moreover, a high areal capacity of 4.5 mAh cm(-2) at 0.2 C with the sulfur loading of 5.1 mg cm(-2) can be achieved. The present work may provide new insight into the design of high-performance sulfur-based cathodes for Li-S batteries.