Atomic-level design rules of metal-cation-doped catalysts: manipulating electron affinity/ionic radius of doped cations for accelerating sulfur redox kinetics in Li–S batteries

A general affinity/ionic radius ( E A / r ) rule as the selection criteria of cation dopants for designing efficient cation doped Li–S catalysts is proposed, and a low E A / r value of doped cations greatly promotes sulfur redox in Li–S batteries.