Lithium metal-sulfur and lithium ion-sulfur secondary batteries containing a nano-structured cathode and processes for producing same

Abstract

An electrochemical cell comprising an anode, electrolyte or an electrolyte/separator combination, and a nano-structured cathode, wherein the cathode comprises: (a) an integrated nano-structure of electrically conductive nanometer-scaled filaments that are interconnected to form a porous network of electron-conducting paths comprising pores with a size smaller than 100 nm (preferably smaller than 10 nm), wherein the filaments have a transverse dimension less than 500 nm (preferably less than 100 nm); and (b) powder or salt of lithium-containing sulfide (lithium polysulfide) disposed in the pores, or a thin coating of lithium-containing sulfide deposited on a nano-scaled filament surface wherein the lithium-containing sulfide is in contact with, dispersed in, or dissolved in electrolyte liquid and the lithium-containing sulfide-to-filament weight ratio is between 1/10 and 10/1 which is measured when the cell is in a fully discharged state. The cell exhibits an exceptionally high specific energy and a long cycle life.