Amorphous MoS ₃ as the sulfur-equivalent cathode material for room-temperature Li–S and Na–S batteries

Significance We propose a concept of “sulfur-equivalent cathode materials,” and reason that instead of using problematic elemental sulfur, one can use sulfur-containing compounds as the alternatives with a comparable electrochemical property but free of any polysulfide generation. We demonstrate here the great potential of amorphous MoS 3 as such a sulfur-equivalent cathode material for room-temperature Li–S and Na–S batteries. More remarkably, we find that MoS 3 is fully cyclable in the carbonate electrolyte (which is known to kill conventional sulfur cathodes) under a relatively high temperature of 55 °C. MoS 3 can also be used as the cathode material of even more challenging Na–S batteries to enable an impressive performance.