A sulfur electrode exhibiting strong polysulfide chemisorption using a porous N, S dual-doped carbon is reported. The synergistic functionalization from the N and S heteroatoms dramatically modifies the electron density distribution and leads to much stronger polysulfide binding. X-ray photoelectron spectroscopy studies combined with ab initio calculations reveal strong Li+-N and S-n(2-)-S interactions. The sulfur electrodes exhibit an ultralow capacity fading of 0.052% per cycle over 1100 cycles.