Production process for alkali metal-sulfur batteries having high volumetric and gravimetric energy densities

Abstract

Process for producing an alkali metal-sulfur battery, comprising: (a) Preparing a first conductive porous structure; (b) Preparing a second conductive porous structure; (c) Injecting or impregnating a first suspension into pores of the first conductive porous structure to form an anode electrode, wherein the first suspension contains an anode active material, an optional conductive additive, and a first electrolyte; (d) Injecting or impregnating a second suspension into pores of the second conductive porous structure to form a cathode electrode, wherein the second suspension contains a cathode active material (selected from sulfur, lithium polysulfide, sodium polysulfide, sulfur-polymer composite, organo-sulfide, sulfur-carbon composite, sulfur-graphene composite, or a combination thereof), an optional conductive additive, and a second electrolyte; and (e) Assembling the anode electrode, a separator, and a cathode electrode into the battery.

1 . A process for producing an alkali metal-sulfur battery, wherein said alkali metal is selected from lithium (Li) and/or sodium (Na), said process comprising:
 (A) Assembling a porous cell framework composed of a first conductive porous structure as a cathode current collector, an anode current collector, and a porous separator disposed between said anode and cathode current collectors; wherein said first conductive porous structure has a thickness no less than 200 μm and at least 70% by volume of pores and said anode current collector has two opposed primary surfaces and at least one of the two primary surfaces contains a layer of sodium or lithium metal or alloy having at least 50% by weight of sodium or lithium element in said alloy;   (B) Preparing a first suspension of a cathode active material dispersed in a first liquid electrolyte, wherein said cathode active material is selected from sulfur, lithium polysulfide, sodium polysulfide, sulfur-polymer composite, organo-sulfide, sulfur-carbon composite, sulfur-graphene composite, or a combination thereof; and   (C) Injecting said first suspension into pores of said first conductive porous structure to form a cathode electrode to an extent that said cathode active material constitutes an electrode active material loading no less than 7 mg/cm 2 , and wherein said anode, said separator, and said cathode are assembled in a protective housing before or after said injecting step is conducted.   
     
     
         2 . The process of  claim 1 , wherein said cathode active material is selected from sulfur bonded to pore walls of said cathode current collector, sulfur bonded to or confined by a carbon or graphite material, sulfur bonded to or confined by a polymer, sulfur-carbon compound, metal sulfide M x S y , wherein x is an integer from 1 to 3 and y is an integer from 1 to 10, and M is a metal element selected from Li, Na, K, Mg, Ca, a transition metal, a metal from groups 13 to 17 of the periodic table, or a combination thereof. 
     
     
         3 . The process of  claim 1 , wherein said conductive porous structure comprises metal foam, metal web or screen, perforated metal sheet-based structure, metal fiber mat, metal nanowire mat, conductive polymer nano-fiber mat, conductive polymer foam, conductive polymer-coated fiber foam, carbon foam, graphite foam, carbon aerogel, carbon xerox gel, graphene foam, graphene oxide foam, reduced graphene oxide foam, carbon fiber foam, graphite fiber foam, exfoliated graphite foam, or a combination thereof. 
     
     
         4 . The process of  claim 1 , wherein a cathode thickness-to-cathode current collector thickness ratio is from 0.8/1 to 1/0.8, and/or said cathode active material constitutes an electrode active material loading greater than 15 mg/cm 2 , and said cathode current collector has a thickness no less than 300 μm. 
     
     
         5 . The process of  claim 1 , wherein said cathode active material is supported by a functional material or nano-structured material selected from the group consisting of:
 (A) A nano-structured or porous disordered carbon material selected from particles of a soft carbon, hard carbon, polymeric carbon or carbonized resin, meso-phase carbon, coke, carbonized pitch, carbon black, activated carbon, nano-cellular carbon foam or partially graphitized carbon;   (B) A nano graphene platelet selected from a single-layer graphene sheet or multi-layer graphene platelet;   (C) A carbon nanotube selected from a single-walled carbon nanotube or multi-walled carbon nanotube;   (D) A carbon nano-fiber, nano-wire, metal oxide nano-wire or fiber, conductive polymer nano-fiber, or a combination thereof;   (E) A carbonyl-containing organic or polymeric molecule;   (F) A functional material containing a carbonyl, carboxylic, or amine group to reversibly capture sulfur;   and combinations thereof.   
     
     
         6 . The process of  claim 1 , wherein said anode contains an alkali ion source selected from an alkali metal, an alkali metal alloy, a mixture of alkali metal or alkali metal alloy with an alkali intercalation compound, an alkali element-containing compound, or a combination thereof. 
     
     
         7 . The process of  claim 1 , wherein said anode contains an alkali intercalation compound selected from petroleum coke, carbon black, amorphous carbon, activated carbon, hard carbon, soft carbon, templated carbon, hollow carbon nanowires, hollow carbon sphere, natural graphite, artificial graphite, lithium or sodium titanate, NaTi 2 (PO 4 ) 3 , Na 2 Ti 3 O 7 , Na 2 C 8 H 4 O 4 , Na 2 TP, Na x TiO 2  (x=0.2 to 1.0), Na 2 C 8 H 4 O 4 , carboxylate based materials, C 8 H 4 Na 2 O 4 , C 8 H 6 O 4 , C 8 H 5 NaO 4 , C 8 Na 2 F 4 O 4 ,C 10 H 2 Na 4 O 8 , C 14 H 4 O 6 , C 14 H 4 Na 4 O 8 , or a combination thereof. 
     
     
         8 . The process of  claim 1 , wherein said first liquid electrolyte is selected from aqueous electrolyte, an organic electrolyte, ionic liquid electrolyte, mixture of an organic electrolyte and an ionic electrolyte, or a mixture thereof with a polymer. 
     
     
         9 . The process of  claim 8 , wherein said aqueous electrolyte contains a sodium salt or a lithium salt dissolved in water or a mixture of water and alcohol. 
     
     
         10 . The process of  claim 9 , wherein said sodium salt or lithium salt is selected from Na 2 SO 4 , Li 2 SO 4 , a mixture thereof, NaOH, LiOH, NaCl, LiCl, NaF, LiF, NaBr, LiBr, NaI, LiI, or a mixture thereof. 
     
     
         11 . The process of  claim 8 , wherein said organic electrolyte contains a liquid organic solvent selected from the group consisting of 1,3-dioxolane (DOL), 1,2-dimethoxyethane (DME), tetraethylene glycol dimethylether (TEGDME), poly(ethylene glycol) dimethyl ether (PEGDME), diethylene glycol dibutyl ether (DEGDBE), 2-ethoxyethyl ether (EEE), sulfone, sulfolane, ethylene carbonate (EC), dimethyl carbonate (DMC), methylethyl carbonate (MEC), diethyl carbonate (DEC), ethyl propionate, methyl propionate, propylene carbonate (PC), gamma-butyrolactone (γ-BL), acetonitrile (AN), ethyl acetate (EA), propyl formate (PF), methyl formate (MF), toluene, xylene, methyl acetate (MA), fluoroethylene carbonate (FEC), vinylene carbonate (VC), allyl ethyl carbonate (AEC), a hydrofloroether, and combinations thereof. 
     
     
         12 . The process of  claim 8 , wherein said organic electrolyte contains an alkali metal salt selected from lithium perchlorate (LiClO 4 ), lithium hexafluorophosphate (LiPF 6 ), lithium borofluoride (LiBF 4 ), lithium hexafluoroarsenide (LiAsF 6 ), lithium trifluoro-metasulfonate (LiCF 3 SO 3 ), bis-trifluoromethyl sulfonylimide lithium (LiN(CF 3 SO 2 ) 2 , Lithium bis(oxalato)borate (LiBOB), lithium oxalyldifluoroborate (LiBF 2 C 2 O 4 ), lithium oxalyldifluoroborate (LiBF 2 C 2 O 4 ), Lithium nitrate (LiNO 3 ), Li-Fluoroalkyl-Phosphates (LiPF3(CF 2 CF 3 ) 3 ), lithium bisperfluoroethysulfonylimide (LiBETI), sodium perchlorate (NaClO 4 ), potassium perchlorate (KClO 4 ), sodium hexafluorophosphate (NaPF 6 ), potassium hexafluorophosphate (KPF 6 ), sodium borofluoride (NaBF 4 ), potassium borofluoride (KBF 4 ), sodium hexafluoroarsenide, potassium hexafluoroarsenide, sodium trifluoro-metasulfonate (NaCF 3 SO 3 ), potassium trifluoro-metasulfonate (KCF 3 SO 3 ), bis-trifluoromethyl sulfonylimide sodium (NaN(CF 3 SO 2 ) 2 ), sodium trifluoromethanesulfonimide (NaTFSI), bis-trifluoromethyl sulfonylimide potassium (KN(CF 3 SO 2 ) 2 ), or a combination thereof. 
     
     
         13 . The process of  claim 8 , wherein said ionic liquid electrolyte contains an ionic liquid solvent selected from a room temperature ionic liquid having a cation selected from tetra-alkylammonium, di-, tri-, or tetra-alkylimidazolium, alkylpyridinium, dialkyl-pyrrolidinium, dialkylpiperidinium, tetraalkylphosphonium, trialkylsulfonium, or a combination thereof. 
     
     
         14 . The process of  claim 13 , wherein said ionic liquid solvent is selected from a room temperature ionic liquid having an anion selected from BF 4   − , B(CN) 4   − , CH 3 BF 3   − , CH 2 CHBF 3   − , CF 3 BF 3   − , C 2 F 5 BF 3   − , n-C 3 F 7 BF 3   − , n-C 4 F 9 BF 3   − , PF 6   − , CF 3 CO 2   − , CF 3 SO 3   − , N(SO 2 CF 3 ) 2   − , N(COCF 3 )(SO 2 CF 3 ) − , N(SO 2 F) 2   − , N(CN) 2   − , C(CN) 3   − , SCN − , SeCN − , CuCl 2   − , AlCl 4   − , F(HF) 2.3   − , or a combination thereof. 
     
     
         15 . A process for producing an alkali metal-sulfur battery, wherein said alkali metal is selected from lithium (Li) and/or sodium (Na), said process comprising:
 (A) Preparing at least one or a plurality of electrically conductive porous structures, and one or a plurality of wet cathode layers of a cathode active material with a liquid electrolyte, wherein said cathode active material is selected from sulfur, lithium polysulfide, sodium polysulfide, sulfur-polymer composite, organo-sulfide, sulfur-carbon composite, sulfur-graphene composite, or a combination thereof, and wherein said conductive porous layers contain interconnected conductive pathways and at least 80% by volume of pores;   (B) Preparing an anode electrode having an anode current collector that has two opposed primary surfaces wherein at least one of the two primary surfaces is deposited with a layer of alkali metal or alkali metal alloy having at least 50% by weight of Na and/or Li element in said alloy;   (C) Placing a porous separator layer in contact with said anode electrode;   (D) Stacking and consolidating a desired number of said porous layers and a desired number of said wet cathode layers in an alternating sequence to form a cathode electrode in contact with said porous separator, wherein said cathode electrode has a thickness no less than 200 μm; wherein said step (D) is conducted before or after step (B); and   (E) Assembling and sealing said anode electrode, porous separator, and cathode electrode in a housing to produce said alkali metal battery;   wherein said cathode active material has a material mass loading no less than 10 mg/cm 2  in said cathode electrode.   
     
     
         16 . The Process of  claim 15  wherein said wet cathode layers of a cathode active material mixed with a liquid electrolyte of step (A) are mixed with a conductive additive. 
     
     
         17 . The process of  claim 15 , wherein said cathode active material is selected from sulfur bonded to pore walls of said cathode current collector, sulfur bonded to or confined by a carbon or graphite material, sulfur bonded to or confined by a polymer, sulfur-carbon compound, metal sulfide M x S y , wherein x is an integer from 1 to 3 and y is an integer from 1 to 10, and M is a metal element selected from Li, Na, K, Mg, Ca, a transition metal, a metal from groups 13 to 17 of the periodic table, or a combination thereof. 
     
     
         18 . The process of  claim 15 , wherein said conductive porous layers are selected from metal foam, metal web or screen, perforated metal sheet-based structure, metal fiber mat, metal nanowire mat, conductive polymer nano-fiber mat, conductive polymer foam, conductive polymer-coated fiber foam, carbon foam, graphite foam, carbon aerogel, carbon xerox gel, graphene foam, graphene oxide foam, reduced graphene oxide foam, carbon fiber foam, graphite fiber foam, exfoliated graphite foam, or a combination thereof. 
     
     
         19 . The process of  claim 15 , wherein a cathode thickness-to-cathode current collector thickness ratio is from 0.8/1 to 1/0.8, and/or said cathode active material constitutes an electrode active material loading greater than 15 mg/cm 2 , and said cathode current collector has a thickness no less than 300 μm. 
     
     
         20 . The process of  claim 15 , wherein said conductive porous layers contain interconnected conductive pathways and at least 90% by volume of pores