Ultrahigh‐Content CoP Cluster as a Dual‐Atom‐Site Electrocatalyst for Accelerating Polysulfides Conversion in Li–S Batteries

Abstract

AbstractSingle‐atom catalysts (SACs) show high catalytic efficiency in accelerating conversion of lithium polysulfides (LiPS), and are thus promising for suppressing the shuttle effect observed in lithium−sulfur batteries (LSBs); however, single‐atom catalytic sites with low content of catalysts largely restrict their catalytic effect. Herein, a CoP cluster supported by a N‐doped carbon matrix (CoP cluster/NC) with atomic‐level dispersion and an ultrahigh content (25.5 wt.%) of Co atoms is fabricated via an in situ low‐temperature phosphorization strategy and employed as a dual‐atom‐site catalyst for catalyzing LiPS conversion. The CoP cluster/NC with abundant unsaturated CoP coordination provides dual‐atom sites of Co and P to dynamically adsorb/desorb sulfur species and Li+ ions, respectively, synergistically promoting the conversion of LiPS. The dual‐atom‐site catalytic mechanism is evidenced by substantial characterizations including X‐ray absorption fine structure measurements and density functional theory calculations. Consequently, the S@CoP cluster/NC cathode shows superior cycling and rate performance. Even at a high sulfur loading of 6.2 mg cm−2, a high areal capacity of 6.5 mAh cm−2 that surpasses most commercial lithium–ion batteries can be achieved. This study opens a new avenue in the development of advanced catalysts with new catalytic mechanisms for high‐performance LSBs.