Alkali metal-sulfur secondary battery containing a pre-sulfurized cathode and production process

A rechargeable alkali metal-sulfur cell comprising:

• an anode active material layer,
• an optional anode current collector,
• a porous separator and/or an electrolyte,
• a pre-sulfurized active cathode layer produced by:
• (a) preparing an integral layer of a mesoporous structure of a carbon, graphite, metal, or conductive polymer, wherein said mesoporous structure comprises mesoscaled pores of 2-50 nm and a specific surface area greater than 100 m2/g and wherein said carbon, graphite, metal, or conductive polymer is selected from chemically etched or expanded soft carbon, chemically etched or expanded hard carbon, exfoliated activated carbon, chemically etched or expanded carbon black, chemically etched multi-walled carbon nanotube, nitrogen-doped carbon nanotube, boron-doped carbon nanotube, chemically doped carbon nanotube, ion-implanted carbon nanotube, chemically treated multi-walled carbon nanotube with an inter-planar separation no less than 0.4 nm, chemically expanded carbon nanofiber, chemically activated carbon nanotube, chemically activated graphite fiber, chemically activated carbonized polymer fiber, chemically treated coke, activated mesophase carbon, mesoporous carbon, electrospun conductive nanofiber, highly separated vapor-grown carbon or graphite nanofiber, highly separated carbon nanotube, carbon nanowire, metal nanowire, metal-coated nanowire or nanofiber, conductive polymer-coated nanowire or nanofiber, or a combination thereof, and wherein said mesoporous structure comprises 0-49% by weight of sulfur or sulfur-containing compound pre-loaded therein and an optional binder material of 0-10% by weight;
• (b) preparing an electrolyte comprising a non-aqueous solvent and a sulfur source dissolved or dispersed in said solvent;
• (c) preparing an anode;
• (d) bringing said integral layer of mesoporous structure and said anode in ionic contact with said electrolyte and imposing an electric current between said anode and said integral layer of mesoporous structure, serving as a cathode, with a sufficient current density for a sufficient period of time to electrochemically deposit nanoscaled sulfur particles or coating in said mesopores to form said pre-sulfurized active cathode layer, wherein said particles or coating have a thickness or diameter smaller than 3 nm and occupy a weight fraction of greater than 80% based on the total weights of said sulfur particles or coating and said integral layer combined, have a thickness or diameter smaller than 5 nm and occupy a weight fraction of greater than 90% based on the total weights of said sulfur particles or coating and said integral layer combined, or have a thickness or diameter smaller than 10 nm and occupy a weight fraction of greater than 95% based on the total weights of said sulfur particles or coating and said integral layer combined;
• and
• (e) depositing an element Z to said mesoporous structure and said Z element is selected from Sn, Sb, and/or Bi;
• and
• an optional cathode current collector,
• wherein said alkali metal-sulfur cell is selected from lithium-sulfur cell, sodium-sulfur cell, or potassium-sulfur cell.