TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Cell: In the aqueous lithium sulfur electrochemical cell, the active sulfur species comprises active sulfur species dissolved in the aqueous electrolyte. The active sulfur concentration in the aqueous electrolyte prior to initially operating the cell is selected from a value that is greater than 0.5-11 molar sulfur, and 12 molar sulfur, or a value that is greater than 13-15 molar sulfur and 16 molar sulfur. The active sulfur concentration in the aqueous electrolyte prior to initially operating the cell is about 17 molar sulfur. Just prior to initially operating the cell: (i) the concentration of the dissolved active sulfur species in the electrolyte is greater than 1 molar sulfur; and (ii) the active stoichiometric ratio of active sulfur to lithium dissolved in the electrolyte, exclusive of any non-active lithium sulfur salts, is represented by the chemical formula selected from lithium sulfide (Li2S); Li2Sx (x not greater than 1); Li2Sx (1 not less than x less than or equal to 5); Li2Sx (4 not less than x not less than 5); Li2Sx (3 not less than x not less than 4); Li2Sx (2 not less than x not less than 3); Li2S2; Li2S3; Li2S4; Li2S5; and Li2Sx (x not greater than 5). Also, just prior to initially operating the cell: (i) the concentration of the dissolved active sulfur species in the electrolyte is greater than 3, 5, 10, 12 or 15 molar sulfur; and (ii) the stoichiometric ratio of active sulfur to lithium dissolved in the electrolyte, exclusive of any non-active lithium sulfur salts, is represented by the chemical formula selected from Li2Sx (2 less than or equal to x less than or equal to 5). Likewise, just prior to initially operating the cell: (i) the concentration of the dissolved active sulfur species in the electrolyte is greater than or equal to 12 or greater than or equal to 15 molar sulfur; and (ii) the stoichiometric ratio of active sulfur to lithium dissolved in the electrolyte, exclusive of any non-active lithium sulfur salts, is represented by the chemical formula selected from Li2Sx (4 less than or equal to x less than or equal to 5), or Li2S5. Just prior to initially operating the cell: (i) the concentration of the dissolved active sulfur species in the electrolyte is greater than 1 molar sulfur; and (ii) the stoichiometric ratio of active sulfur to lithium dissolved in the electrolyte, exclusive of any non-active lithium sulfur salts, is represented by the chemical formula Li2S. Moreover, just prior to initially operating the cell all of the active sulfur species dissolved in the electrolyte is fully reduced. The concentration of the fully reduced active sulfur species is greater than 1 molar sulfur. Just prior to initial cell operation the active sulfur species in contact with the aqueous electrolyte further comprises solid phase lithium sulfide, where the moles of active sulfur of solid phase lithium sulfide is greater than the moles of active sulfur dissolved in the electrolyte by a factor selected from at least 2, at least 3, at least 5 and at least 10. The weight ratio of water in the catholyte relative to the active solid phase lithium sulfide is selected from: a weight ratio less than or equal to 10, less than or equal to 6, less than or equal to 5, less than or equal to 4, less than or equal to 3, less than or equal to 2 and less than or equal to 1.5. The full charge capacity of the cell is derived from the dissolved active sulfur species and the solid phase lithium sulfide. Upon cell fabrication and prior to initial cell operation the anode electroactive material is substantially devoid of active lithium. The initial operation is to electrochemically charge the cell. The anode electroactive material is selected from intercalation materials capable of electrochemically intercalating lithium upon electro-reduction, alloying materials capable of electrochemically alloying with lithium upon electro-reduction, and materials capable of forming lithium inter-metallic phases upon electro-reduction. The anode electroactive material is an intercalation material capable of electrochemically intercalating lithium upon electro-reduction. The anode electroactive material is selected from intercalating carbon, silicon, and a composite of silicon combined with an intercalating carbon. The anode electroactive material is selected from lithium metal (preferred), lithium metal alloy, and lithium metal intermetallic comprising active lithium. Prior to initial cell operation the anode is devoid of active lithium, the anode comprising a current collector having a surface suitable for plating lithium metal during, and where the initial cell operation is an electrochemical charge where lithium metal is plated onto the current collector. The current collector surface comprises a metal, preferably copper. Water is the main and the only liquid solvent in the electrolyte. The volume percent of water in the electrolyte relative to the total liquid volume in the electrolyte is selected from greater than 5-80%, and greater than 90%. The aqueous electrolyte comprises dissolved lithium ions but is substantially devoid of other dissolved metal cations. The aqueous electrolyte is selected from neutral having a pH about 7, acidic having a pH less than 7, and alkaline having a pH greater than 7. The pH of the aqueous electrolyte is between 9 and 14. The electrolyte further comprises at least one non-aqueous solvent, where the non-aqueous solvent is protic, and where the protic solvent is organic. The protic non-aqueous solvent is selected from alcohols, diols, triols, and polyols. The protic solvent is methanol or ethylene glycol. The amount of non-aqueous solvent in the catholyte is sufficient to depress the melting temperature of the catholyte to a value below that selected from -5 degrees C, -10 degrees C, -20 degrees C, -30 degrees C and -40 degrees C. The active sulfur species comprises solid phase active sulfur, where the solid phase active sulfur is selected from solid phase elemental sulfur and solid phase organo-sulfur compound. Just prior to initial cell operation the cathode is devoid of elemental sulfur. The solid electron transfer medium comprises a core component selected from a porous core component and a planar core component. The porous core component is a porous matrix structure, where the porous matrix structure is selected from a fibrous matrix structure, a foam matrix structure, and a mesh matrix structure. The porous matrix structure is selected from a metal porous matrix structure, a carbonaceous porous matrix structure, an inorganic glassy porous matrix structure, an inorganic ceramic porous matrix structure and a polymeric porous matrix structure. The core component is composed of a material that is electronically insulating, and the core component itself is an insulator; and/or a material that is electronically conductive, and the core component itself is conductive. The electron transfer medium further comprises an exterior surface layer component covering the core component, the exterior surface layer defining an exterior surface in contact with the catholyte, where at least a portion of the exterior surface in contact with the catholyte is defined by a material having a high overpotential for H2 evolution that is greater than 100 mV. The high overpotential material is selected from metals, metal alloys and metal sulfides, where the high overpotential material is a metal selected from cobalt, copper, manganese, zinc, lead, cadmium, tellurium, indium, gallium, nickel and zinc. The high overpotential material is a metal sulfide selected from cobalt sulfide, copper sulfide, manganese sulfide, zinc sulfide, lead sulfide, cadmium sulfide, indium sulfide, tellurium sulfide, gallium sulfide, nickel sulfide and zinc sulfide. The anode electroactive material is lithium metal or a lithium metal alloy. The anode structure further comprises a substantially impervious lithium ion conductive protective membrane architecture having a first and second major surface where the first surface is in direct contact with the aqueous catholyte, and the membrane architecture is configured in the cell to protect the electroactive material from contacting the aqueous electrolyte. The second major surface of the membrane architecture directly contacts the anode electroactive material. The aqueous electrolyte is substantially devoid of molecular oxygen and has a molecular oxygen concentration that is less than a value selected from 1000 ppm, 500 ppm, 100 ppm, 50 ppm, and 10 ppm. Preferred Method: In making the aqueous lithium sulfur cell, the active sulfur species are fully reduced. The electrolyte comprises dissolved lithium sulfide. The electrolyte has an active stoichiometric ratio of lithium sulfide (Li2S). The cell further comprises solid phase lithium sulfide in contact with the electrolyte. The cathode is devoid of elemental sulfur. The method further comprises charging the cell, where the charging step is the initial electrochemical operation, and where the charging reaction involves electro-reductive lithiation of the anode electroactive material and electro-oxidation of dissolved active sulfur species at the surface of the electron transfer medium. The anode electroactive material is devoid of electroactive lithium prior to the start of the initial charging step. The amount of active sulfur species and lithium ions in the as-fabricated cell is sufficient for providing the necessary ampere-hour capacity to fully charge the cell during the initial charging step. The method of making the aqueous electrolyte comprises the steps of: providing water; deoxygenating the water; adding one or more sulfur precursor materials and reacting the precursor materials with each other and/or with the water to form dissolved electroactive sulfur species. The first precursor material is lithium sulfide and the second precursor material is elemental sulfur. The only sulfur precursor material is lithium sulfide. The method of making the electron transfer medium comprises the steps of: providing a core component comprising a porous matrix material; and applying an exterior surface layer to cover the core component, where the surface layer component material facilitates electrochemical redox of electroactive sulfur species present in the catholyte and has an overpotential for H2 evolution that is at least 100 mV. The method of applying the exterior surface layer is selected from electroless deposition, physical vapor deposition, and electroplating. The method of making the electron transfer medium further comprises the step of sulfidizing the exterior surface layer. The electrolyte comprises dissolved active sulfur species and the sulfidization step is performed in-situ in the cell via contact with the electrolyte, where the sulfidization step is performed ex-situ in a sulfur containing environment outside of the cell. The ex-situ sulfidizing step comprises the steps of: (i) providing the electron transfer medium; (ii) placing the electron transfer medium in a sulfur containing environment outside of the cell; (iii) maintaining the electron transfer medium in the sulfur containing environment for a sufficient time to effect sulfidization; and (iv) removing the electron transfer medium from the sulfur containing environment, for eventual configuration in the cell. Alternatively, operating the aqueous lithium sulfur cell comprises: (i) providing a lithium sulfur cell, comprising: an anode structure comprising an electroactive material; a cathode comprising a solid electron transfer medium having surface that facilitates electrochemical reduction of the active sulfur species and has a high overpotential for hydrogen evolution; an aqueous electrolyte in contact with the electron transfer medium; and active sulfur species in contact with the aqueous electrolyte; where the anode electroactive material is isolated from direct contact with the aqueous electrolyte and in particular the anode electroactive material does not contact water of the aqueous electrolyte or the active sulfur species; and (ii) electrochemically cycling the cell including discharging the cell to a cell voltage below 2.3 volts vs. lithium. In a second alternative case, operating the aqueous lithium sulfur cell comprises: (i) providing an aqueous lithium sulfur cell, comprising: an anode structure comprising an electroactive material; a cathode comprising a solid electron transfer medium having surface that facilitates electrochemical reduction of the active sulfur species and has a high overpotential for hydrogen evolution; an aqueous electrolyte in contact with the electron transfer medium; and active sulfur species in contact with the aqueous electrolyte; where the anode electroactive material is isolated from direct contact with the aqueous electrolyte and in particular the anode electroactive material does not contact water of the aqueous electrolyte or the active sulfur species; and (ii) electrochemically cycling the cell including discharging the cell to a cell voltage below 2.2 volts. In a third alternative case, operating the aqueous lithium sulfur cell comprises: (i) providing an aqueous lithium sulfur cell, comprising: an anode structure comprising an electroactive material; a cathode comprising a solid electron transfer medium having surface that facilitates electrochemical reduction of the active sulfur species and has a high overpotential for hydrogen evolution; an aqueous electrolyte in contact with the electron transfer medium; and active sulfur species in contact with the aqueous electrolyte; where the anode electroactive material is isolated from direct contact with the aqueous electrolyte and in particular the anode electroactive material does not contact water of the aqueous electrolyte or the active sulfur species; and (ii) electrochemically cycling the cell including discharging the cell to a cell voltage below 2.1 volts. In a fourth alternative case, operating the aqueous lithium sulfur cell comprises: (i) providing a lithium sulfur cell, comprising: an anode structure comprising an electroactive material; a cathode comprising a solid electron transfer medium having surface that facilitates electrochemical reduction of the active sulfur species and has a high overpotential for hydrogen evolution; an aqueous electrolyte in contact with the electron transfer medium; and active sulfur species in contact with the aqueous electrolyte; where the anode electroactive material is isolated from direct contact with the aqueous electrolyte and in particular the anode electroactive material does not contact water of the aqueous electrolyte or the active sulfur species; and (ii) electrochemically cycling the cell including discharging the cell to a cell voltage below 2.0 volts. The anode electroactive material is devoid of active lithium, and the method further comprises the step of performing an initial electrochemical charging of the cell. Preferred System: In thelithium sulfur flow cell system, the anode electroactive material is selected from intercalation materials, insertion materials, alloying materials and intermetallic materials. The anode electroactive material is intercalating carbon. EXAMPLE - No suitable example given.