Single-Atom Cobalt\nCatalyst with Boron and Nitrogen\nCodoped Graphene (Co-BN-G) Enables Adsorption and Catalytic Conversion\nof Polysulfides for High-Performance Lithium–Sulfur Batteries

In lithium–sulfur batteries, the shuttling effect\nand sluggish\nredox conversion of soluble polysulfides lead to unsatisfactory sulfur\nutilization and capacity retention. In this research, we used a one-pot\nhydrothermal method to prepare graphene with single-atom Co and B,\nN codoped as a sulfur host in Li–S batteries, thereby suppressing\nthe shuttling effect and facilitating the redox conversion of lithium\npolysulfides (LiPSs). A series of characterizations demonstrated that\ndual doping of B and N introduces more lattice defects and structural\ndeformations in graphene oxide, thus enhancing its adsorption of polysulfides.\nSimultaneously, single-atom cobalt can also polarize adsorption and\naccelerate the conversion reaction of LiPSs. The Li–S cell\nwith the as-prepared Co-BN-G sulfur host materials exhibited an excellent\ncapacity of 1034 mAh g<sup>–1</sup> at 0.5 C and satisfactory\ncycle performance (retention of 69% over 500 cycles). Even at a rate\nof 2 C, a discharge capacity of 851 mAh g<sup>–1</sup> is achieved.\nThe results show that the Co-BN-G configuration efficiently captures\nLiPSs and enhances their rate conversion kinetics in redox reactions,\ndemonstrating significant practical potential.