High-performance cathode materials for lithium sulfur batteries from lignosulfonate
Methods of making cathodes for lithium-sulfur batteries are disclosed, in addition to cathodes and batteries containing the cathodes. A method of making a cathode is disclosed which includes extracting lignosulfonate from brown liquor, pyrolyzing the lignosulfonate, carbonizing the pyrolyzed lignosulfonate to form a carbon-sulfur compound, and forming the carbon-sulfur compound into a cathode. A cathode for a lithium-sulfur battery is disclosed which includes pyrolized lignosulfonate recovered from brown liquor, and carbon. The pyrolized lignosulfonate and carbon are suspended in a matrix having a substantially homogenous distribution of sulfur. A battery is disclosed in which an anode including an electrolye, lithium, is provided along with a membrane separate and a carbon comprising a carbon-sulfur compound derived from lignosulfonates.
1. A method of making a cathode, comprising:
extracting lignosulfonate from brown liquor;
pyrolyzing the lignosulfonate;
carbonizing the pyrolyzed lignosulfonate to form a carbon-sulfur material; and
forming the carbon-sulfur material into a cathode.
2. The method of claim 1 , further comprising: annealing the carbon-sulfur material.
3. The method of claim 1 , wherein the pyrolizing comprises dehydrating the lignosulfonate at 80° C.
4. The method of claim 1 , wherein the carbon-sulfur material has a substantially homogeneous distribution of sulfur within a carbon matrix.
5. The method of claim 1 , wherein the carbonizing comprises heating the pyrolyzed lignosulfonate to 300° C. at 20° C./min prior to maintaining an isothermal state for one hour.
6. The method of claim 2 , wherein the carbonizing comprises heating the pyrolyzed lignosulfonate to 300° C. at 20° C./min prior to maintaining an isothermal state for one hour.
7. The method of claim 6 , wherein the annealing comprises increasing the temperature from 300° C. to 800° C. at 20° C/min prior to maintaining an isothermal state for up to 8 hours.
8. The method of claim 1 , wherein the carbonizing comprises:
heating the pyrolyzed lignosulfonate to 300° C.,
maintaining an isothermal state for one hour,
heating the pyrolized lignosulfonate to 800° C.,
maintaining an isothermal state for three hours,
cooling the pyrolized lignosulfonate to 100° C.,
ramping the temperature up to 155° C. at 1° C./min, and
holding the temperature at 155° C. for sixteen hours.
9. The method of claim 1 , wherein the carbonizing yields a sulfuric powder.
10. The method of claim 1 , further comprising forming a lithium sulfur battery comprising the formed cathode.