Cathode and cathode materials for lithium sulfur batteries
Provided are electrode active materials with a porous structure and including a metal, that when loaded with sulfur serve as electrochemically superior cathode active materials. The metal structures are optionally used on their own, are coated with another material, or coats another porous structure such as a porous carbon structure that allows for excellent retention of both sulfur and polysulfides, are conductive themselves, and show long term stability and excellent cycle life.
1. An electrode comprising:
an electrically conductive porous particle forming an electrochemically active material, said electrically conductive porous particle comprising a metal nitride or metal oxynitride, said structure infiltrated with sulfur such that the sulfur is encapsulated into pores of the electrically conductive porous particle, wherein said metal nitride or metal oxynitride comprises Cr, Fe, B, Mo, W, Co, Nb, Ni, or combinations thereof, wherein said metal nitride or metal oxynitride is electrically conductive.
2. The electrode of claim 1 further comprising a binder wherein said binder comprises polytetrafluoroethylene, polyvinylidene difluoride, latex binder, carboxymethylcellulose, poly(acrylic acid), polyvinyl alcohol, or combinations thereof.
3. The electrode of claim 1 further comprising one or more electrically conductive fillers.
4. The electrode of claim 3 , wherein said electrically conductive filler comprises carbon.
5. The electrode of claim 4 , wherein said carbon is carbon black, carbon nanotube, carbon nanofiber, synthetic graphite including expanded graphite, graphite nanosheet, graphite nanoplatelet, graphene sheet, non-synthetic graphite (including natural graphite and coke), graphitized carbon nano-fiber, or combinations thereof.
6. The electrode of claim 1 , wherein said metal nitride or metal oxynitride mixes with porous carbon.
7. The electrode of claim 6 , wherein said metal nitride or metal oxynitride coats a surface of said porous carbon.
8. The electrode of claim 1 , wherein said metal nitride or metal oxynitride comprises Cr, Fe, B, Mo, W, Co, Ni, or combinations thereof.
9. An electrochemically active material comprising:
an electrically conductive porous particle comprising a metal, said porous particle is electrically conductive, said porous particle infiltrated with sulfur such that the sulfur is encapsulated into pores of the of the porous particle, wherein said porous particle further comprises an additive coating at least a portion of the surface of said metal.
10. The material of claim 9 , wherein said additive is a nitriding agent.
11. The material of claim 9 , wherein said additive is an organic molecule.
12. The material of claim 11 , wherein said additive is capable of forming a carbon nitride structure.
13. The material of claim 9 , wherein said additive is cyanamide.
14. The material of claim 9 , wherein said metal is coated onto a surface of a porous scaffold material.
15. The material of claim 14 , wherein said porous scaffold material comprises carbon.
16. The material of claim 14 , wherein said porous scaffold material is in the form of a microporous sphere, mesoporous nanoparticle, porous hollow carbon, graphene oxide sheet, porous carbon nanofiber, hollow carbon fiber, metal foam, metal mesh, or combinations thereof.
17. The material of claim 9 , wherein said metal is a metal nitride or metal oxynitride.
18. The material of claim 17 , wherein said metal comprises Si, Cr, Fe, B, V, Mo, W, Zr, Co, Ni, or combinations thereof.