Sulfur-infused carbon for secondary battery materials

Abstract

In one aspect, a method of producing a sulfur-infused carbonaceous material as a cathode material for use in a Li—S battery is described, including providing a carbonaceous material; mixing elemental sulfur with the carbonaceous material; and heating the mixed sulfur and the carbonaceous material at a temperature from about 445° C. to about 1000° C. for a period of time and under a pressure greater than 1 atm to generate a sulfur vapor to infuse the carbonaceous material to result in a sulfur-infused carbonaceous material. In another aspect, a reactor for producing a sulfur-infused carbonaceous material as a cathode material for use in a Li—S battery is described, including a reactor body capable of withstanding a pressure from about 1 atm to about 150 atm; and an inner sulfur-resistant layer at the inner surface of the reactor, wherein the inner layer is inert to sulfur vapor at a temperature from about 450° C. to about 1000° C.

What is claimed is: 
     
         1 . A method of producing a sulfur-infused carbonaceous material as a cathode material for use in a Li—S battery, comprising:
 providing a carbonaceous material; 
 mixing elemental sulfur with the carbonaceous material; and 
 heating the mixed sulfur and the carbonaceous material at a temperature from about 445° C. to about 1000° C. for a period of time and under a pressure greater than 1 atm to generate a sulfur vapor to infuse the carbonaceous material with sulfur to result in a sulfur-infused carbonaceous material. 
 
     
     
         2 . The method of  claim 1 , wherein the sulfur-infused carbonaceous material comprises from about 10 wt % to about 99 wt % of sulfur after a single heating operation. 
     
     
         3 . The method of  claim 1 , wherein the sulfur-infused carbonaceous material comprises more than 50 wt % of sulfur after a single heating operation. 
     
     
         4 . The method of  claim 1 , wherein the sulfur-infused carbon comprises more than 60 wt % sulfur after a single heating operation. 
     
     
         5 . The method of  claim 1 , wherein the method further comprises cooling the heated mixed sulfur and the carbonaceous material. 
     
     
         6 . The method of  claim 1 , wherein the period is about 1 minute to about 4 hours. 
     
     
         7 . The method of  claim 1 , wherein the carbonaceous material is selected from the group consisting of coal, polyacrylonitrile, resorcinol-formaldehyde resins, KetJen, aerogel, coconut, bamboo, plant derived carbon, CNT, graphene, acetylene black, Super P and a combination thereof. 
     
     
         8 . The method of  claim 1 , wherein providing a carbonaceous material further comprises activating the carbonaceous material. 
     
     
         9 . The method of  claim 8 , wherein activating the carbonaceous material comprises using a base selected from the group consisting of KOH, NaOH, LiOH, and combinations thereof. 
     
     
         10 . The method of  claim 9 , wherein the activated carbonaceous material has a surface area greater than about 1000 m 2 /g. 
     
     
         11 . The method of  claim 1 , wherein the temperature is from 500° C. to about 800° C. 
     
     
         12 . The method of  claim 1 , wherein the temperature is from 500° C. to about 600° C. 
     
     
         13 . The method of  claim 1 , wherein the pressure is between about 2 atm to about 150 atm. 
     
     
         14 . The method of  claim 1 , wherein the temperature is about 500° C. to about 600° C. and the pressure is about 2 atm to 3 atm. 
     
     
         15 . The method of  claim 1 , wherein the temperature is about 700° C. to about 800° C. and the pressure is about 20 atm to 30 atm. 
     
     
         16 . The method of  claim 1 , wherein the temperature is about 1000° C. and the pressure is about 140 atm to 150 atm. 
     
     
         17 . The method  claim 1 , wherein providing a carbonaceous material comprises providing an activated coal. 
     
     
         18 . The method of  claim 17 , wherein the activated coal has a heavy metal ion impurity of less than 100 ppm and a surface area greater than 1000 m 2 /g; 
     
     
         19 . The method of  claim 18 , wherein providing an activated coal comprises:
 purifying coal to contain less than 100 ppm of heavy ion impurities;   activating coal by heating a mixture of the purified coal and a base; and   sintering the activated coal at a temperature in the range of 900° C.-1300° C. to provide an activated coal having a surface area greater than 1000 m 2 /g.   
     
     
         20 . The method of  claim 19  wherein purification comprises:
 treating coal with leaching solution containing acids, oxidizers, and water; and 
 washing the coal with water to remove impurities. 
 
     
     
         21 . The method of  claim 17 , wherein the activation step comprises heating to temperatures between 500 and 900° C. 
     
     
         22 . The method of  claim 17 , further comprising pulverizing the coal. 
     
     
         23 . The method of  claim 22  further comprising heating to a temperature of 900° C. for 8 to 10 hours prior to pulverizing. 
     
     
         24 . The method of  claim 19 , wherein purifying coal comprises using an acid selected from the group consisting of HCl, H 2 SO 4 , HNO 3 , and combinations thereof. 
     
     
         25 . The method of  claim 19 , wherein activating coal comprises using a base selected from the group consisting of KOH, NaOH, LiOH, and combinations thereof. 
     
     
         26 . The method of  claim 19 , wherein sintering comprises using a gas environment selected from the group consisting of N 2 , CO 2 , Ar, He, H 2 , CO, NO x , and combinations thereof. 
     
     
         27 . The method of  claim 19 , comprising providing activated coal having a surface area between 1000 and 2000 m 2 /g. 
     
     
         28 . The method of  claim 1 , wherein providing a carbonaceous material comprises providing activated carbonaceous material having graphitic content between 1 and 20 mass %. 
     
     
         29 . The method of  claim 1 , wherein providing a carbonaceous material comprises providing activated carbonaceous material having graphitic content between 5 and 10 mass %. 
     
     
         30 . The method of  claim 1 , wherein the sulfur-infused carbon comprises between 60 wt % and 95 wt % sulfur after in a single heating operation. 
     
     
         31 . A Li—S battery, comprising:
 a cathode comprising a coal-sulfur composite, the composite comprising activated coal having a heavy metal ion impurity of less than 100 ppm, a surface area greater than 1000 m 2 /g and at least 60 wt % sulfur; 
 an electrolyte; and 
 a lithium anode. 
 
     
     
         32 . The battery of  claim 31 , wherein the electrolyte comprises a thermally stable ionic liquid, lithium salt, and aprotic solvent. 
     
     
         33 . The battery of  claim 31  comprising activated coal having a surface area between 1000 and 2000 m 2 /g. 
     
     
         34 . The battery of any of  claims 31 , comprising activated coal having graphitic content between 1 and 20 mass %. 
     
     
         35 . The battery of any of  claims 34  comprising activated coal having graphitic content between 5 and 10 mass %. 
     
     
         36 . The battery of any one of  claims 31 , wherein initial battery capacity is between 400 and 1200 mAh/g. 
     
     
         37 . The battery of any one of  claims 36 , wherein initial battery capacity is between 700 and 1000 mAh/g. 
     
     
         38 . A reactor for producing a sulfur-infused carbonaceous material as a cathode material for use in a Li—S battery, comprising:
 a reactor body configured to withstand a pressure from about 1 atm to about 150 atm; and 
 an inner sulfur-resistant layer at the inner surface of the reactor body, wherein the inner layer is inert to sulfur vapor at a temperature from about 450° C. to about 1000° C. 
 
     
     
         39 . The reactor of  claim 38 , wherein the reactor body and the inner layer are made of the same material. 
     
     
         40 . The reactor of  claim 39 , wherein the material withstands a pressure from about 1 atm to about 150 atm and is layer is inert to sulfur vapor at a temperature from about 450° C. to about 1000° C. 
     
     
         41 . The reactor of  claim 39 , wherein the material is selected from the group consisting of titanium, molybdenum, Tungsten and a combination thereof. 
     
     
         42 . The reactor of  claim 38 , wherein the reactor body and the inner layer are made of different materials. 
     
     
         43 . The reactor of  claim 42 , wherein the reactor body is made of a material selected from the groups consisting of titanium, molybdenum, Tungsten, stainless steel, and a combination thereof. 
     
     
         44 . The reactor of  claim 42 , wherein the inner layer is made of a material selected from the group consisting of titanium, molybdenum, Tungsten, quartz, alumina, silicon carbide, Nucerite 7040 (Pfaudler), Nitraglass 6510 (Pfaudler), SiO 2 , and a combination thereof. 
     
     
         45 . The reactor of  claim 42 , wherein the inner layer is a sheath or liner configured to slide in and out of the reactor body. 
     
     
         46 . The reactor of  claim 42 , wherein the inner layer is a coating coated on the inner surface of the reactor body.