NOVELTY - Electrochemical cell comprises an anode, a separator and/or electrolyte, and a nano-structured cathode, where 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, and (b) powder or salt of lithium-containing sulfide or lithium polysulfide disposed in the pores or a thin coating of lithium-containing sulfide deposited on a nano-scaled filament surface.    USE - The electrochemical cell is useful as power sources for electric vehicle (EV), hybrid electric vehicle (HEV), and portable electronic devices, such as lap-top computers and mobile phones.    ADVANTAGE - The electrochemical cell prevents lithium metal dendrite-induced internal short circuit and thermal runaway problems thus enabling long and stable cycling response, and can be prepared with high specific capacity and high specific energy in an economical manner.    DETAILED DESCRIPTION - Electrochemical cell comprises an anode, a separator and/or electrolyte, and a nano-structured cathode, where 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, in which the filaments have a transverse dimension less than 500 nm, and (b) powder or salt of lithium-containing sulfide or lithium polysulfide disposed in the pores or a thin coating of lithium-containing sulfide deposited on a nano-scaled filament surface, where the lithium-containing sulfide is in contact with the electrolyte, or dispersed or dissolved in a liquid electrolyte, and the lithium-containing sulfide-to-filament weight ratio is 1/10-10/1 which is measured when the cell is in a fully discharged state. INDEPENDENT CLAIMS are included for producing an electrochemical cell, comprising: either (i) preparing a structure of electrically conductive nanometer-scaled filaments that are interconnected to form a porous network of electron-conducting paths, (ii) depositing a nano-scaled coating of sulfur or sulfur compound onto a surface of the nano-scaled filaments to obtain a coated nano-structure having a coating thickness less than 500 nm, (iii) obtaining a cathode by chemically or electro-chemically converting the coating of sulfur or sulfur compound into a lithium polysulfide to obtain an integrated structure of nano-filaments comprising lithium polysulfide, and (iv) combining the cathode with an anode and electrolyte or an electrolyte-separator assembly to form the electrochemical cell; or the step (i) as above per se, (iia) immersing the nano-structure as a first electrode in a lithium polysulfide-containing electrolyte, immersing a lithium metal or lithium-containing conductor as a second electrode in the electrolyte, and imposing a current onto the first and second electrodes to electrochemically produce a lithium polysulfide-coated nano-structure for use as a cathode, and (iiia) combining the cathode with an anode and electrolyte or an electrolyte-separator assembly to form the electrochemical cell.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic representation of a lithium metal-sulfur cell with a nano-structured anode.