Apparatus and method for production of sulfur-host composite materials

A method for forming quasi-spherical particles of a sulfur-host composite material comprising the steps:

• (i) providing a particulate host material and elemental sulfur to a screw extruder;
• (ii) mixing the particulate host material and elemental sulfur in the screw extruder at a temperature of from 115 to 450° C. to create a stream comprising molten sulfur and a solid particulate host material;
• (iii) passing the stream comprising molten sulfur and solid particulate host material through an atomiser to form an atomised stream comprising a plurality of particles formed from solid particulate host material surrounded by molten sulfur;
• and
• (iv) cooling the atomised stream to form solid particles comprising a particulate host material core and a shell formed from elemental sulfur, which particles have a quasi-spherical shape.

A core-shell microparticle or nanoparticle comprising:

• a core formed from a host material;
• and
• a shell formed from elemental sulfur,
• wherein the microparticle or nanoparticle has a quasi-spherical shape.

A method for forming an electrode comprising the steps:

• (i) providing a particulate host material and elemental sulfur to a screw extruder;
• (ii) mixing the particulate host material and elemental sulfur in the screw extruder at a temperature of from 115 to 450° C. to create a stream comprising molten sulfur and solid particulate host material;
• (iii) cooling the stream comprising molten sulfur and solid particulate host material to a temperature of from 115 to 135° C.;
• and
• (iv) extruding the cooled stream from step (iii) to form a self-standing electrode.