Synthesis method for sulfur-porous carbon composites with tunable crystallinity and morphology for lithium/sulfur batteries

A method of making a sulfur-carbon composite, the method comprising:

• providing an amorphous carbon powder comprising nanometer-sized pores disposed in a container;
• gaseously coupling a staging tube containing a sulfur source to the amorphous carbon powder;
• evacuating the container and the staging tube to remove ambient air and surface-adsorbed gaseous species;
• backfilling the container to about ⅔ atmosphere absolute (ATA) with a high purity inert gas;
• desorbing the amorphous carbon powder by:
• heating the container proximal to the amorphous carbon powder;
• evacuating the container to about ⅓ ATA to at least partially remove gaseous species and moisture;
• backfilling the container to about ⅔ ATA with the high purity inert gas;
• and
• repeating heating, evacuating, and backfilling until a predetermined desorption temperature is reached;
• cooling the container to room temperature under the high purity inert gas;
• transferring the sulfur source from the staging tube onto the desorbed amorphous carbon powder in the container;
• evacuating the container to a vacuum and sealing the desorbed amorphous carbon powder and the sulfur source in the container;
• applying a temperature gradient across the container, with a high temperature zone adjacent the desorbed amorphous carbon powder and the sulfur source at a sulfur infiltration temperature, and a low temperature zone distal to the desorbed amorphous carbon powder and the sulfur source;
• maintaining the temperature gradient for a duration sufficient to vaporize and infiltrate sulfur into the desorbed amorphous carbon powder to form a composite;
• and
• cooling the container to condense excess sulfur away from the composite.