Ultrastable cathodes for lithium sulfur batteries

1. A cathode, comprising:

a current collector comprising copper; and

an active material layer comprising 70 wt % of an active material, a conductive material and a binder;

wherein the active material layer is disposed over the current collector, and the active material comprises 52 wt % Li 2 S, 15 wt % Cu 2 S and 33 wt % nitrogen-doped graphene nanosheets.

2. The cathode of claim 1 , wherein the current collector comprises a copper foil.

3. The cathode of claim 1 , wherein the binder comprises polyvinylidene fluoride or polyethylene oxide.

4. The cathode of claim 1 , wherein the conductive material comprises carbon black.

5. The cathode of claim 1 , wherein the Li 2 S comprises microsized lithium sulfide.

6. The cathode of claim 1 , wherein the active material layer has a thickness of 25 microns to 200 microns.

7. A lithium-sulfur battery comprising:

a cathode;

an anode; and

a lithium ion conducting electrolyte;

wherein the cathode comprises:

a current collector comprising copper; and

an active material layer comprising 70 wt % of an active material, a conductive material and a binder;

wherein the active material layer is disposed over the current collector, and the active material comprises 52 wt % Li 2 S, 15 wt % Cu 2 S and 33 wt % nitrogen-doped graphene nanosheets.

8. The lithium-sulfur battery of claim 7 , wherein the anode does not include lithium.

9. A method of producing a cathode, comprising:

forming a slurry containing 70 wt % of active material, a conductive material, a binder and a solvent; and

disposing the slurry over a current collector;

wherein the active material comprises 52 wt % Li 2 S, 15 wt % Cu 2 S and 33 wt % nitrogen-doped graphene nanosheets.

10. The method of claim 9 , further comprising drying the slurry disposed over the current collector in a furnace.