Lubricant-impregnated surfaces for electrochemical applications, and devices and systems using the same

Abstract

In certain embodiments, the invention relates to an electrochemical device having a liquid lubricant impregnated surface. At least a portion of the interior surface of the electrochemical device includes a portion that includes a plurality of solid features disposed therein. The plurality of solid features define a plurality of regions therebetween. A lubricant is disposed in the plurality of regions which retain the liquid lubricant in the plurality of regions during operation of the device. An electroactive phase comes in contact with at least the portion of the interior surface. The liquid lubricant impregnated surface introduces a slip at the surface when the electroactive phase flows along the surface. The electroactive phase may be a yield stress fluid.

What is claimed is: 
     
         1 . An electrochemical device comprising:
 an interior surface, at least a first portion of which comprises a plurality of solid features disposed thereon, the plurality of solid features defining a plurality of regions therebetween, and a liquid lubricant disposed in the plurality of regions, the plurality of solid features retaining the liquid lubricant in the plurality of regions during operation of the device, thereby providing a liquid lubricant impregnated surface; and   an electroactive phase in contact with at least the first portion of the interior surface, wherein the liquid lubricant impregnated surface introduces a slip at the surface (e.g., where a ratio of slip velocity against mean velocity (u w /ū) is greater than 0.9) when the electroactive phase flows along the surface (e.g., thereby providing low shear rate and high slip ratio (u w /ū) at the surface and promoting plug flow of the electroactive phase within the device).   
     
     
         2 . The electrochemical device of  claim 1 , wherein the electroactive phase is a non-Newtonian fluid. 
     
     
         3 . The electrochemical device of  claim 2 , wherein the electroactive phase is a yield-stress fluid. 
     
     
         4 . The electrochemical device of  claim 3 , wherein the electroactive phase has a yield-stress between 1 Pa to 2 kPa. 
     
     
         5 . The electrochemical device of any one of the preceding claims, wherein the electroactive phase flows along the first portion of the interior surface such that the first portion is substantially free from residue left by the electroactive phase along its path of flow (e.g., less than 10%, less than 5%, less than 1%, less than 0.5%, less than 0.1% of residue of electroactive phase remaining). 
     
     
         6 . The electrochemical device of any one of the preceding claims, wherein the first portion enables flowing of the electroactive phase solely due to gravity. 
     
     
         7 . The electrochemical device of any one of the preceding claims, wherein the electroactive phase comprises at least one solvent and at least one electrolyte. 
     
     
         8 . The electrochemical device of  claim 7 , wherein the electrolyte is a lithium-containing salt (e.g., LiPF 6 , LiBF 4 , LiTFSI, LiFSI, LiClO 4 , LiAlCl 4 , LiGaCl 4 ) in an organic solvent or combination of solvents or in an aqueous-based solvent or combination of solvents; or wherein the electrolyte is selected from the group consisting of iron/chromium, bromine/polysulfide, vanadium, zinc/bromine, lithium polysulfide, vanadium, tris(bipyridine)nickel(II)tetrafluoroborate/tris(bipyridine)iron(II)tetrafluoroborate (Ni(Bpy) 3 (BF 4 ) 2 /Fe(BPy) 3 (BF 4 ) 2 ), tris(bipyridine)ruthenium(II) ((Ru(bpy) 3 ] 2+ ), and zinc/cerium. 
     
     
         9 . The electrochemical device of  claim 7 , wherein the solvent is selected from the list consisting of water, alkyl carbonates (e.g., ethylene carbonate, diethyl carbonate, dimethyl carbonate, propylene carbonate), alkyl phosphonates, phosphites, acetonitrile, propylene carbonate, glyme, diglyme, triglyme, tetraglyme, polyglyme, dioxolane (1,3-dioxolane), dimethyl sulfoxide (DMSO), dichloromethane, ethylene carbonate, tetrahydrafuran (THF), methane sulfonic acid, dimethyl ether (DEM), tetraethylene glycol dimethyl ether (TEG-DME) and dimethoxyethane, and any combination or derivative thereof. 
     
     
         10 . The electrochemical device of any one of the preceding claims, wherein the electroactive phase further comprises at least one flame-retardant additives (e.g., trimethlyphosphate (TMP)) and/or at least one ion transport enhancer. 
     
     
         11 . The electrochemical device of any one of the preceding claims, wherein the electroactive phase includes at least one conductive additive selected from the group consisting of: metal carbides, metal nitrides, carbon black, graphitic carbon powder, carbon fibers, carbon microfibers, vapor-grown carbon fibers (VGCF), fullerenes, carbon nanotubes (CNTs), multiwall carbon nanotubes (MWNTs), single wall carbon nanotubes (SWNTs), graphene sheets, and materials comprising fullerenic fragments that are not predominantly a closed shell or tube of the graphene sheet, and any combination or mixture thereof. 
     
     
         12 . The electrochemical device  claim 11 , wherein the conductive additive is carbon black. 
     
     
         13 . The electrochemical device of  claim 12 , wherein the carbon black is present in the electroactive phase in an amount from between 0.25 vol % to 3 vol %. 
     
     
         14 . The electrochemical device of any one of the preceding claims, wherein the liquid lubricant impregnated surface promotes plug flow, wherein a ratio of slip velocity against mean velocity (u w /ū) is greater than 0.9. 
     
     
         15 . The electrochemical device of any one of the preceding claims, wherein at least one of the conditions or any combination of conditions (a) through (e) is satisfied:
 (a) wherein the solid features have an average dimension in a range of up to 200 microns;   (b) wherein the solid features comprise particles;   (c) wherein a ratio of an exposed surface area of the plurality of solid features to an exposed surface area of the liquid lubricant contained in the plurality of regions is less than 0.5;   (d) wherein the solid features comprise particles and wherein an average spacing between adjacent particles or clusters of particles is in a range of up to 200 microns; and   (e) wherein the interior surface (without the plurality of solid features and the liquid lubricant) has a first roll-off angle and wherein the plurality of solid features and the liquid lubricant collectively define a liquid-impregnated surface, the liquid-impregnated surface having a second roll-off angle, the second roll-off angle being less than the first roll-off angle;   
     
     
         16 . The electrochemical device of  claim 15 , wherein the ratio of the exposed surface area of the plurality of solid features to the exposed surface area of the liquid contained in the plurality of regions is less than 0.3. 
     
     
         17 . The electrochemical device of  claim 15 , wherein the ratio of the exposed surface area of the plurality of solid features to the exposed surface area of the liquid contained in the plurality of regions greater than 0 and less than 0.2. 
     
     
         18 . The electrochemical device of  claim 15 , wherein the second roll-off angle is less than 2°. 
     
     
         19 . The electrochemical device of any one of the preceding claims, wherein the electrochemical device is a member selected from the group consisting of: a battery (e.g., flow battery, aqueous battery, non-aqueous battery, metal-air battery), a fuel cell (e.g., gravity-induced flow cell), and a capacitor (e.g., electrolytic capacitor, flow capacitor). 
     
     
         20 . The electrochemical device of any one of  claims 1 - 19 , wherein the first portion passively promotes at least one effect selected from the list consisting of: (i) increases nucleation of insoluble materials (e.g., of reacting material, e.g., insoluble lithium sulfide species) formed during operation of the electrochemical device, (ii) increases growth of insoluble materials (e.g., of reacting material, e.g., insoluble lithium sulfide species) formed during operation of the electrochemical device, (iii) increases precipitation of insoluble materials (e.g., of reacting material, e.g., insoluble lithium sulfide species) formed during operation of the electrochemical device, (iv) increases segregation of insoluble materials (e.g., of reacting material, e.g., insoluble lithium sulfide species) formed during operation of the electrochemical device at desired locations on the internal surface of the electrochemical device. 
     
     
         21 . The electrochemical device of any one of  claims 1 - 19 , wherein the first portion passively promotes at least one effect selected from the list consisting of: (i) inhibits nucleation (e.g., of scale or of reacting material, e.g., insoluble lithium sulfide species), (ii) decreases growth (e.g., of scale or reacting material, e.g., insoluble lithium sulfide species), (iii) inhibits precipitation (e.g., of reacting material, e.g., insoluble lithium sulfide species), (iv) decreases segregation (e.g., of scale or of reacting material, e.g., insoluble lithium sulfide species) at undesired locations (e.g., surfaces that are not electrically connected to the terminals of the battery or are otherwise electrochemically inactive) on the internal surface of the electrochemical device of insoluble materials formed during operation of the electrochemical device. 
     
     
         22 . The electrochemical device of any one of the preceding claims, wherein the first portion passively extends an operating temperature range of the electrochemical device (e.g., the electrochemical device may be operated at lower temperatures, e.g., wherein the liquid-lubricant impregnated surface inhibits crystallization of electroactive phase components). 
     
     
         23 . The electrochemical device of any one of the preceding claims, wherein a second portion (e.g., other than the first portion) of the internal surface does not comprise the plurality of solid features disposed thereon. 
     
     
         24 . The electrochemical device of  claim 23 , wherein the internal surface includes one or more first portions comprising the plurality of solid features disposed thereon and one or more second portions not comprising the plurality of solid features disposed thereon. 
     
     
         25 . The electrochemical device of any one of the preceding claims, wherein the first portion is electronically conductive. 
     
     
         26 . The electrochemical device of any one of the preceding claims, wherein the plurality of solid features comprise an electronically conductive material (e.g., nanoparticles suspended in a percolating network of carbon black in TEG-DME) and/or wherein the liquid lubricant comprises an electronically conductive suspension or polymer solution (e.g., a percolating network of carbon black in a vacuum pump oil (e.g., KRYTOX® 1506)). 
     
     
         27 . The electrochemical device of any one of  claims 1 - 24 , wherein the first portion is ionically conductive. 
     
     
         28 . The electrochemical device of  claim 27 , wherein the plurality of solid features comprise an ion-conducting glass or polymer and wherein the liquid lubricant comprises an ionically conductive liquid (e.g., an electrolyte). 
     
     
         29 . The electrochemical device of any one of the preceding claims, wherein the liquid lubricant is electrochemically stable (e.g., where an amount of side reactions due to the liquid lubricant is less than 5%, less than 3%, or less than 1% of total electrochemical reactions). 
     
     
         30 . The electrochemical device of any one of the preceding claims, wherein the liquid lubricant is thermodynamically stable (e.g., wherein when surface tension of the liquid lubricant is subtracted from surface tension of an electrolyte solvent, the resulting value is greater than zero). 
     
     
         31 . The electrochemical device of any one of the preceding claims, wherein the liquid lubricant is immiscible or partially miscible (e.g., less than 5%, less than 3%, less than 1% miscibility) with the electroactive phase. 
     
     
         32 . The electrochemical device of any one of the preceding claims, wherein the plurality of solid features comprise at least one material selected from the group consisting of: hydrocarbons, (e.g., alkanes, and fluoropolymers (e.g., polytetrafluoroethylene, trichloro(1H,1H,2H,2H-perfluorooctyl)silane (TCS), octadecyltrichlorosilane (OTS), heptadecafluoro-1,1,2,2-tetrahydrodecyltrichlorosilane, fluoroPOSS)), ceramics (e.g., titanium carbide, titanium nitride, chromium nitride, boron nitride, chromium carbide, molybdenum carbide, titanium carbonitride, electroless nickel, zirconium nitride, fluorinated silicon dioxide, titanium dioxide, tantalum oxide, tantalum nitride, diamond-like carbon, fluorinated diamond-like carbon, and/or combinations thereof. Intermetallic compounds may include, for example, nickel aluminide, titanium aluminide, and/or combinations thereof), polymeric materials (e.g., polytetrafluoroethylene, fluoroacrylate, fluorourethane, fluorosilicone, fluorosilane, modified carbonate, chlorosilanes, silicone, polydimethylsiloxane (PDMS), and/or combinations thereof), fluorinated materials, intermetallic compounds, composite materials. 
     
     
         33 . The electrochemical device of any one of the preceding claims, wherein the liquid lubricant is selected from the list consisting of oil-based lubricants (e.g., silicone oils, e.g., 10 cSt silicone oil, 1000 cSt silicone oil); ionic liquids (e.g., BMI-IM, e.g., having ionic conductivity between 1 mS/cm to 10 mS/cm); hexadecane, vacuum pump oils (e.g., perfluorinated vacuum oils), fluorocarbons (e.g., perfluoro-tripentylamine), shear-thinning fluids, shear-thickening fluids, liquid polymers, dissolved polymers, viscoelastic fluids, liquid fluoroPOSS, hydrocarbon liquids, fluorocarbon liquids, and/or electronically conducting liquids (e.g., lubricant suspended with electronically-conducting particles). 
     
     
         34 . The electroactive device of any one of the preceding claims, comprising:
 a first volume comprising the electroactive phase (e.g., flow electrode, e.g., lithium polysulfide suspension);   a second volume separated from the first volume by a separator (e.g., membrane, e.g. ion-permeable membrane), wherein the separator spatially separates a positive current collector and a negative current collector, wherein the electroactive phase flows from the first volume to the second volume during operation of the electroactive device.   
     
     
         35 . The electroactive device of  claim 34 , wherein the separator is coated with or comprises a liquid-lubricant impregnated surface. 
     
     
         36 . The electroactive phase of  claim 34  or  35 , wherein the first portion is disposed at an interior surface of the first volume (e.g., the liquid lubricant impregnated surface is disposed at the interior surface of the first volume). 
     
     
         37 . An electroactive device, comprising:
 a positive electrode current collector;   a negative electrode current collector; and   an ion-permeable membrane separating the positive current collector and the negative current collector;   a positive electrode disposed between the positive electrode current collector and the ion-permeable membrane, the positive electrode current collector and the ion-permeable membrane defining a positive electroactive zone accommodating the positive electrode; and   a negative electrode disposed between the negative electrode current collector and the ion-permeable membrane; the negative electrode current collector and the ion-permeable membrane defining a negative electroactive zone accommodating the negative electrode,   wherein at least a portion of the positive electrode current collector surface that comes into contact with the positive electrode and/or at least a portion of the negative electrode current collector surface that comes into contact with the negative electrode comprises a plurality of solid features disposed thereon, the plurality of solid features defining a plurality of regions therebetween, and a liquid lubricant disposed in the plurality of regions, the plurality of solid features retaining the liquid lubricant in the plurality of regions during operation of the device, thereby providing a liquid lubricant impregnated surface,   wherein the liquid lubricant impregnated surface introduces a slip at the surface (e.g., where a ratio of slip velocity against mean velocity (u w /ū) is greater than 0.9) when the positive electrode or the negative electrode flows along the surface and promotes plug flow of the positive electrode or the negative electrode along the surface.   
     
     
         38 . The electroactive device of  claim 37 , further comprising a positive electrode storage tank and a negative electrode storage tank, wherein at least a portion of an internal surface of the positive electrode storage tank and/or the negative electrode storage tank comprises or is coated with a liquid lubricant impregnated surface. 
     
     
         39 . The electroactive device of  claim 37 , further comprising a positive electrode storage tank and a negative electrode storage tank, wherein the positive electrode storage tank and the negative electrode storage tank are connected to the electroactive zone via piping, wherein at least a portion of an internal surface of the piping comprises or is coated with a liquid lubricant impregnated surface. 
     
     
         40 . The electroactive device of any one of  claims 37 - 39 , wherein the ion-permeable membrane comprises or is coated with a liquid-lubricant impregnated surface.