Abstract: New dual temperature electrochemical methods and systems for the production of sodium metal from sodium polysulfides have been discovered. The technology provides high conductivity for sodium ions and extended service life for the electrochemical cell.

Abstract: New dual temperature electrochemical methods and systems for the production of sodium metal from sodium polysulfides have been discovered. The technology provides high conductivity for sodium ions and extended service life for the electrochemical cell.

Abstract: Lithium-ion-conducting ceramic materials are disclosed having characteristics of high lithium-ion conductivity at low temperatures, good current efficiency, and stability in water and corrosive media under static and electrochemical conditions. Some general formulas for the lithium-ion-conducting materials include MI1+x+z??MIIIxMIVayMIVb2?x?yMVzP3?zO12 and MI1+x+4z??MIIIxMIVayMIVb2?x?y?zP3O12, wherein MI comprises Li, Na, or mixtures thereof; 0.05<x<0.5, 0.05<y<2, 0?z<3, and 0??<0.5; MIII comprises Al, Hf, Sc, Y, La, or mixtures thereof; MIVa comprises Zr, Ge, Sn, or mixtures thereof; MIVb comprises Ti; and MV comprises Si, Ge, Sn, or mixtures thereof. In some cases, the lithium-ion conducting materials are formed through a process in which the materials' powdered precursors are milled after being calcined and before being sintered. The milling process may include using milling media of multiple sizes.

Abstract: Pressureless sintering of silicon carbide with fracture toughness in excess of about 4 MPa-m1/2 as measured by the single-edge precracked beam (SEPB) technique while maintaining a density greater than 3.1 g/cc for compositions with SiC greater than about 94 wt. % is made possible through the use of metallic Al to promote sintering and grain growth. Boron and carbon may be used as traditional sintering aids, with nitrogen to suppress grain growth, and additions of yttrium and/or lanthanide elements to promote intergranular fracture.

Abstract: Pressureless sintering of silicon carbide with fracture toughness in excess of about 4 MPa-m1/2 as measured by the single-edge precracked beam (SEPB) technique while maintaining a density greater than 3.1 g/cc for compositions with SiC greater than about 94 wt. % is made possible through the use of metallic Al to promote sintering and grain growth. Boron and carbon may be used as traditional sintering aids, with nitrogen to suppress grain growth, and additions of yttrium and/or lanthanide elements to promote intergranular fracture.