A rechargeable lithium-sulfur cell comprising an anode, a separator and/or electrolyte, and a sulfur cathode, wherein the cathode comprises (a) exfoliated graphite worms that are interconnected to form a porous, conductive graphite flake network comprising pores having a size smaller than 100 nm; and (b) nano-scaled powder or coating of sulfur, sulfur compound, or lithium polysulfide disposed in the pores or coated on graphite flake surfaces wherein the powder or coating has a dimension less than 100 nm. The exfoliated graphite worm amount is in the range of 1% to 90% by weight and the amount of powder or coating is in the range of 99% to 10% by weight based on the total weight of exfoliated graphite worms and sulfur (sulfur compound or lithium polysulfide) combined. The cell exhibits an exceptionally high specific energy and a long cycle life.