WP Nanocrystals on N,P Dual-Doped Carbon Nanosheets with Deeply Analyzed Catalytic Mechanisms for Lithium-Sulfur Batteries

The use of transition-metal phosphides (TMPs) as catalytic materials to accelerate kinetics of lithium polysulfide (LiPS) conversion has unique advan-tages. Nevertheless, simple and low-cost prepara-tion strategies are still required for the synthesis of novel TMPs with satisfactory performance. Impor-tantly, the in-depth understanding of the effect of intrinsic interaction between catalytic materials and LiPSs on the promoted kinetics remains limited. Herein, a novel structure of tungsten phosphide (WP) nanocrystals decorated on N,P codoped car-bon sheets (WP/NPC) with uniform dispersion is designed by a structure-oriented strategy to pro-mote LiPS redox kinetics. The electrochemical kinet-ics measurements coupled with density functional theory computations and in situ/ex situ character-izations demonstrate that the strong interaction through W-S bonding and the favorable interfacial charge state of WP-LiPSs promote the nucleation and dissociation of Li2S. Benefiting from this supe-riority, the WP/NPG-based lithium-sulfur batteries indicate significantly improved electrochemical performance with good cycling life and excellent rate capability. This work provides a methodology for the design of TMP-involved electrode materials and a fundamental understanding of the intrinsic mechanism of catalysis.