Strong lithium-polysulfide anchoring effect of amorphous carbon for lithium–sulfur batteries

Solving the shuttle effect caused by lithium polysulfide (LPS) dissolution is important in lithium−sulfur batteries. The anchoring of LPSs to carbon combined with sulfur is a method of suppressing the shuttle effect. This first-principles study is the first to report that amorphous carbon offers the best ability to anchor LPSs. The adsorption energies of LPSs on amorphous carbon are at least six times higher than those on graphene and at least two times higher than those on pyridinic-N doped graphene. The LPSs adsorbed on amorphous carbon undergo significant molecular distortion and/or partial dissociation due to the S-to-C electron transfer of 1.2–1.8 e per molecule, as well as the formation of strong bonds between both the Li and S atoms and the sp- and sp2-site C atoms. We propose an amorphous carbon−graphite hybrid anchoring material, because amorphous carbon can strongly capture LPSs and graphite can act as an electron channel.