Surface-modified electrodes, preparation methods and electrochemical uses

Abstract

The present technology concerns modifying the surface of an electrode film with a succession of thin layers, each with a thickness for example of 15 microns or less, with the first thin layer comprising an inorganic compound (such as a ceramic) in a solvating polymer, the inorganic compound being present in the first thin layer at a ratio by mass of inorganic compound to solvating polymer in the range from about 1:20 to about 20:1. Electrochemical cells comprising the modified electrodes are also described, as are secondary batteries comprising them.

Description

[0001] SURFACE-MODIFIED ELECTRODES, PREPARATION METHODS, AND ELECTROCHEMICAL USES

[0002] RELATED REQUEST

[0003] This application claims priority under applicable law from Canadian patent application number 3,128,220 filed on August 13, 2021, the contents of which are incorporated herein by reference in their entirety and for all purposes.

[0004] TECHNICAL FIELD

[0005] The present application relates to electrodes comprising a film of electrode material having at least one modified surface, to methods of manufacturing them and to electrochemical cells comprising them.

[0006] STATE OF THE ART

[0007] Liquid electrolytes used in lithium-ion batteries are flammable and slowly degrade to form a passivation layer on the surface of the lithium film or solid electrolyte interface (SEI), irreversibly consuming lithium, which decreases the Coulombic efficiency of the battery. In addition, lithium anodes undergo significant morphological changes during battery cycling and lithium dendrites are formed. Since these typically migrate through the electrolyte, they can eventually cause short circuits.Safety concerns and the requirement for higher energy density have stimulated research into the development of an all-solid-state rechargeable lithium battery with a polymer or ceramic electrolyte, both of which are more stable toward metallic lithium and reduce lithium dendrite growth. However, the loss of reactivity and poor contact between solid-state interfaces in these all-solid-state batteries remain problematic.

[0008] A simple and more industrially transposable method for protecting the lithium surface is to cover its surface with a polymer or a polymer / lithium salt mixture by spray coating, immersion coating, spin coating or even using the so-called doctor blade method (N. Delaporte, et al., Front. Mater., 2019, 6, 267). The chosen polymer must then be stable against lithium and ionically conductive at low temperatures. In a way, the polymer layer deposited on the lithium surface should be comparable to the solid polymer electrolytes (SPE) generally reported in the literature, which have a glass transition (T v) low in order to remain rubbery at room temperature and to maintain lithium conductivity similar to that of a liquid electrolyte. To accommodate the deformation of lithium during cycling and especially to avoid the formation of lithium dendrites, the polymer must have good flexibility and must be characterized by a high Young's modulus.

[0009] Some examples of polymers used in this type of protective layer include polyacrylic acid (PAA) (N.-W. Li, et al., Angew. Chem. Int. Ed., 2018, 57, 1505-1509), vinylidene-co-acrylonitrile polycarbonate (S.M. Choi et al., J. Power Sources, 2013, 244, 363-368), poly(ethylene glycol) dimethacrylate (Y.M. Lee, et al., J. Power Sources, 2003, 119-121, 964-972), PEDOT-co-PEG copolymer (G. Ma, et al., J. Mater. Chem. A, 2014, 2, 19355-19359 and I.S. Kang, et al., J. Electrochem. Soc., 2014, 161 (1), A53-A57), the polymer from the direct polymerization of acetylene on lithium (DG Belov, et al., Synth. Met., 2006, 156, 745-751), in situ polymerized ethyl a-cyanoacrylate (Z. Hu, et al., Chem. Mater, 2017, 29, 4682-4689), and a polymer formed from the copolymer Kynar™ 2801 and the curable monomer 1,6-hexanediol diacrylate (N. -S. Choi, et al., Solid State Ion., 2004, 172, 19-24).The latter group also studied the incorporation of an ionic receptor into the polymer blend (N. -S. Choi, et al., Electrochem. Commun., 2004, 6, 1238-1242).

[0010] Some studies have been carried out on the incorporation of solid fillers, typically ceramics, into a polymer for the modification of lithium surfaces. For example, inorganic fillers (e.g., AI2O3, TiO2, BaTiOs) were mixed with a polymer to give an organic-inorganic hybrid composite electrolyte.

[0011] A mixture of freshly synthesized spherical CU3N particles of less than 100 nm and a styrene butadiene rubber (SBR) copolymer was doctor-coated onto the lithium surface (Y. Liu, et al., Adv. Mater, 2017, 29, 1605531). Upon contact with lithium, CU3N is converted into highly lithium-conducting U3N. Li4TisOi2 / Li (LTO / Li) cells were assembled with a liquid electrolyte, and improved electrochemical performance was achieved using lithium protected by a mixture of CU3N and SBR. A 20 pm protective layer composed of ALCh particles (1.7 pm average diameter) and polyvinylidene hexafluoropropylene fluoride (PVDF-HFP) deposited on the surface of lithium has been proposed to improve the lifetime of lithium-oxygen batteries (DJ Lee, et al., Electrochem. Commun., 2014, 40, 45-48). CO3O4-Super P / Li batteries with this protective layer and a liquid electrolyte.The effect of similarly modified lithium was also studied by Gao and colleagues (HK Jing et al., J. Mater. Chem. A, 2015, 3, 12213-12219), although the focus was on improving lithium-sulfur batteries. In this example, 100 nm ALCh spheres were used with PVDF as a binder, and the mixture prepared in DM F solvent was spin-coated onto a lithium foil. Battery assembly was then carried out with a liquid electrolyte.

[0012] A 25 pm porous polyimide layer with AhOs as filler (particle size of about 10 nm) to limit lithium growth has also been proposed (see Z. Peng et al., J. Mater. Chem. A, 2016, 4, 2427-2432). This method involves the formation of a film called a "skin layer" by contacting lithium with an additive present in the liquid electrolyte (such as fluoroethylene carbonate (FEC), vinylene carbonate (VC) or hexamethylene diisocyanate (HDI)). Cu / LiFePCL electrochemical cells comprising this liquid electrolyte were tested to demonstrate the usefulness of the polyimide / AhCh layer to inhibit dendrite formation and electrolyte degradation.

[0013] The protective layers described in the three preceding paragraphs are porous and suitable for use with a liquid electrolyte, which can penetrate into them. This type of layer is therefore not suitable for use with a solid electrolyte, which must be able to be in intimate contact with the surface of the electrode (or its protective layer) and allow the conduction of ions from the electrolyte to the active electrode material.

[0014] SUMMARY

[0015] According to a first aspect, the present technology relates to an electrode comprising an electrode film modified by a first thin layer and a second thin layer, wherein: the electrode film comprises a first and a second surface, the first surface being optionally pretreated; the first thin layer comprises an inorganic compound in a solvating polymer and optionally an ionic salt and / or a plasticizer, the first thin layer being disposed on the first surface of the electrode film and having an average thickness of about 15 μm or less, the mass ratio of "inorganic compound:solvating polymer" in the first thin layer is in the range of about 1:20 to about 20:1; and the second thin layer comprises a solvating polymer, an ionic salt and optionally a plasticizer, the second thin layer being disposed on the first thin layer and having an average thickness of about 15 μm or less;wherein the solvating polymer of the first layer is the same as or different from the solvating polymer of the second layer.;

[0016] In one embodiment, the solvating polymer of the first thin layer is crosslinked, and / or the solvating polymer of the second thin layer is crosslinked. In another embodiment, the solvating polymer of the first thin layer is uncrosslinked, and / or the solvating polymer of the second thin layer is uncrosslinked.

[0017] According to one embodiment, the electrode film is a current collector, for example comprising an electron-conducting solid support, such as a metal foil or grid (such as copper, nickel, etc.), a carbon or carbon-comprising film (such as carbon paper, self-supporting graphene, etc.), or other solid support (polymer, glass, etc.) comprising an electron-conducting layer (such as a current collector print).

[0018] According to another embodiment, the electrode film comprises a metal film, for example comprising lithium (for example comprising less than 1000 ppm (or less than 0.1% by mass) of impurities), or an alloy comprising lithium. In one embodiment, the metal film comprises an alloy of lithium and an element selected from alkali metals other than lithium (such as Na, K, Rb, and Cs), alkaline earth metals (such as Mg, Ca, Sr, and Ba), rare earth metals (such as Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu), zirconium, copper, silver, bismuth, cobalt, manganese, zinc, aluminum, silicon, tin, antimony, cadmium, mercury, lead, molybdenum, iron, boron, indium, thallium, nickel, and germanium (e.g., Zr, Cu, Ag, Bi, Co, Zn, Al, Si, Sn, Sb, Cd, Hg, Pb, Mn, B, In, Tl, Ni, or Ge). According to one embodiment, the alloy comprises at least 75% by mass of lithium, or between 85% and 99.9% by mass of lithium.

[0019] According to another embodiment, the electrode film further comprises a pretreatment layer on the first surface, the latter being in contact with the first thin layer. In one embodiment, the pretreatment layer comprises a compound selected from a silane, a phosphonate, a borate, an organic salt or compound, a carbon (such as graphite, graphene, etc.), an inorganic salt or compound (such as LiF, LisN, U3P, UNO3, U3PO4, etc.), or a thin layer of an element different from a metal of the electrode film or forming an alloy therewith at the surface (such as an element defined above with reference to alloys), said pretreatment layer having an average thickness of less than 5 μm, or less than 3 μm, or less than 1 μm, or less than 500 nm, or less than 200 nm, or less than 100 nm, or even less than 50 nm. According to one embodiment, the first surface of the electrode film is pretreated by stamping.

[0020] According to one embodiment, the inorganic compound is in the form of particles (e.g., spherical, rod-shaped, needle-shaped, etc.). For example, the average particle size may be less than 1 pm, or less than 500nm, or less than 300nm, or less than 200nm, or between 1nm and 500nm, or between 10nm and 500nm, or between 50nm and 500nm, or between 100nm and 500nm, or between 1 nm and 300nm, or between 10nm and 300nm, or between 50nm and 300nm, or between 100nm and 300nm, or between 1 nm and 200nm, or between 10nm and 200nm, or between 50nm and 200nm, or between 100nm and 200nm, or between 1nm and 100nm, or between 10nm and 100nm, or between 25nm and 100nm, or between 50nm and 100nm.

[0021] In another embodiment, the inorganic compound comprises a ceramic. In one embodiment, the inorganic compound is selected from AI2O3, Mg2B20s, Na2O-2B2O3, xMgO yB2O3-zH2O, TiO2, ZrO2, ZnO, Ti20s, SiO2, Cr20s, CeO2, B2O3, B2O, SrBi4Ti40i5, LLTO, LLZO, LAGP, l_ATP, Fe2O3, BaTiOs, Y-UAIO2, a metal / carbon mixture (such as Sn+C, Zn+C, Ni2P+C), molecular sieves and zeolites (e.g., aluminosilicate, mesoporous silica), sulfide ceramics (such as U7P3S11), glass-ceramics (such as LIPON, etc.), and other ceramics, as well as combinations thereof.

[0022] According to an additional embodiment, the particles of the inorganic compound further comprise organic groups covalently grafted to their surface, for example, said groups being chosen from crosslinkable groups (such as organic groups comprising acrylate, methacrylate, vinyl, glycidyl, mercapto, etc. functions), aryl groups, alkylene oxide or poly(alkylene oxide) groups, and other organic groups, or one of their combinations, optionally comprising a spacer group between the organic groups and the particles of the inorganic compound. In one embodiment, the grafted organic groups comprise poly(alkylene oxide) chains attached to the particles of the inorganic compound by a spacer group.In another embodiment, the spacer group is selected from silane or halogenated silane, phosphonate, carboxylate, catechol, (meth)acrylate or poly(meth)acrylate, alkylene or polyalkylene groups, and combinations thereof.

[0023] According to one embodiment, the particles of the inorganic compound have a small specific surface area (e.g., less than 80 m 2 / g, or less than 40 m 2 / g). According to another embodiment, the mass ratio "inorganic compound:solvating polymer" in the first thin layer is in the range of about 2:5 to about 4:1, or about 2:5 to about 2:1, or about 1:2 to about 2:1, or about 4:5 to about 2:1, or about 1:1 to about 2:1, or about 4:5 to about 3:2. According to yet another embodiment, the particles of the inorganic compound have a large specific surface area (e.g., 80 m 2 / g and more, or 120 m 2 / g and more). In yet another embodiment, the mass ratio of "inorganic compound: solvating polymer" in the first thin layer is in the range of about 1:20 to about 2:1, or about 2:5 to about 2:1, about 2:5 to about 6:5, or about 1:20 to about 6:5, or about 2:5 to about 1:1, or about 1:20 to about 1:1, or about 2:5 to about 4:5, or about 1:20 to about 4:5.

[0024] According to an additional embodiment, the average thickness of the first thin layer is between about 0.5 pm and about 15 pm, or between about 1 pm and about 15 pm, or between about 1 pm and about 12 pm, or between about 0.5 pm and about 10 pm, or between about 1 pm and about 10 pm, or between about 2 pm and about 8 pm, or between about 2 pm and about 7 pm, or between 2 pm and about 5 pm. According to another embodiment, the average thickness of the second thin layer is between about 50nm and about 15pm, or between about 0.1pm and about 15pm, or between about 0.5pm and about 15pm, or between about 1pm and about 15pm, or between about 1pm and about 12pm, or between about 0.5pm and about 10pm, or between about 1pm and about 10pm, or between about 2pm and about 8pm, or between about 2pm and about 7pm, or between 2pm and about 5pm, or between 50nm and about 5pm, or between about 0.1pm and about 2pm.According to yet another embodiment, the total average thickness of the first and second thin layers is in the range of about 1 pm to about 30 pm, or about 1 pm to about 25 pm, or about 5 pm to about 25 pm, or about 1 pm to about 20 pm, or about 1 pm to about 16 pm, or about 2 pm to about 12 pm, or about 3 pm to about 15 pm, or about 3 pm to about 12 pm, or about 4 pm to about 15 pm, or about 4 pm to about 12 pm.

[0025] According to another embodiment, the solvating polymer is independently selected from linear or branched polyether polymers (e.g., PEO, PPO, or EO / PO copolymer), poly(dimethylsiloxanes), poly(alkylene carbonates), poly(alkylene sulfones), poly(alkylene sulfamides), polyurethanes, poly(vinyl alcohols), polyacrylonitriles, polymethyl methacrylates, and copolymers thereof, optionally comprising crosslinked units originating from crosslinkable functions (such as acrylate, methacrylate, vinyl, glycidyl, mercapto functions, etc.).

[0026] According to a preferred embodiment, at least one of the first and second thin layers further comprises a plasticizer, for example, the first thin layer and the second thin layer further comprise a plasticizer. In one embodiment, the plasticizer is selected from glycol diether liquids (such as tetraethylene glycol dimethyl ether (TEGDME)), carbonate esters (such as propylene carbonate, ethylene carbonate, fluoroethylene carbonate), lactones (such as γ-butyrolactone), adiponitrile, ionic liquids and the like.

[0027] According to another embodiment, at least one of the first and second thin layers further comprises a lithium salt. In one embodiment, the first thin layer and the second thin layer further comprise a lithium salt.In another embodiment, the lithium salt is selected from lithium hexafluorophosphate (LiPFe), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium 2-trifluoromethyl-4,5-dicyanoimidazolate (LiTDI), lithium 4,5-dicyano-1,2,3-triazolate (LiDCTA), lithium bis(pentafluoroethylsulfonyl)imide (LiBETI), lithium tetrafluoroborate (UBF4), lithium bis(oxalato)borate (LiBOB), lithium nitrate (UNO3), lithium chloride (LiCl), lithium bromide (LiBr), lithium fluoride (LiF), lithium perchlorate (LiCl>4), lithium hexafluoroarsenate (LiAsFe), lithium trifluoromethanesulfonate (LiBr ... lithium (USO3CF3) (LiTf), lithium fluoroalkylphosphate Li[PF3(CF2CF3)3] (LiFAP), lithium tetrakis(trifluoroacetoxy)borate Li[B(OCOCF3)4] (LiTFAB), lithium bis(1,2-benzenediolato(2-)-O,O')borate Li[B(CeO2)2] (LBBB), and a combination thereof.

[0028] According to another embodiment of the first aspect, the electrode further comprises a current collector in contact with the second surface of the electrode film.

[0029] According to a second aspect, the present technology relates to an electrochemical cell comprising a negative electrode and a positive electrode, wherein at least one of the negative electrode and the positive electrode is as defined above. In one embodiment, the negative electrode is as defined above and the positive electrode comprises a film of positive electrode material comprising a positive electrode electrochemically active material, optionally a binder, and optionally an electronically conductive material.

[0030] In one embodiment, the positive electrode electrochemically active material is selected from metal phosphates, lithiated metal phosphates, metal oxides, and lithiated metal oxides. In another embodiment, the positive electrode electrochemically active material is LiM'PC t where M' is Fe, Ni, Mn, Co, or a combination thereof, UV3O8, V2O5F, UV2O5, LiMn2O4, LiM”C>2, where M” is Mn, Co, Ni, or a combination thereof (such as NMC, LiMn x Co y Neither zO2 with x+y+z = 1), Li(NiM'”)O2 (where M'” is Mn, Co, Al, Fe, Cr, Ti, Zr, or a combination thereof), elemental sulfur, elemental selenium, elemental iodine, iron(lll) fluoride, copper(lll) fluoride, lithium iodide, carbon-based active materials, organic cathode active materials (such as polyimide, poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate) (PTMA), tetralithium perylene-3,4,9,10-tetracarboxylate (PTCIJ4), naphthalene-1,4,5,8-tetracarboxylic dianhydride (NTCDA), perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA), TT-conjugated dicarboxylates, and anthraquinone), or a combination of two or more of these materials if compatible with each other.

[0031] In another embodiment, the positive electrode electrochemically active material is in the form of optionally coated particles (e.g., polymer, ceramic, carbon, or a combination of two or more thereof).

[0032] In another embodiment, the positive electrode material film comprises a first and a second surface, the first surface facing the negative electrode and carrying a third thin layer comprising a solvating polymer and an ionic salt, the third thin layer having an average thickness of about 50 μm or less, about 40 μm or less, or about 30 μm or less, or about 15 μm or less, or is between about 0.5 μm and about 50 μm, or between about 5 μm and about 50 μm, or between about 5 μm and about 40 μm, or between about 0.5 μm and about 15 μm, or between about 1 μm and about 15 μm, or between about 1 μm and about 12 μm, or between about 0.5 μm and about 10 μm, or between about 1 μm and about 10 μm, or between about 2 μm and about 8 μm, or between about 2 μm and about 7pm, or between 2pm and about 5pm. In one embodiment, the solvating polymer is as defined above.In another embodiment, the salt is a lithium salt, for example as defined above. According to another embodiment, the third thin layer further comprises a plasticizer, for example as defined above.

[0033] According to an embodiment of the second aspect, the electrochemical cell excludes the presence of a solid polymer electrolyte layer.

[0034] According to an alternative embodiment of the second aspect, the electrochemical cell further comprises a solid electrolyte layer comprising a polymer and a lithium salt. In one embodiment, the polymer of the electrolyte is selected from linear or branched polyether polymers (e.g., PEO, PPO, or EO / PO copolymer), and optionally comprising crosslinkable units), poly(dimethylsiloxanes), poly(alkylene carbonates), poly(alkylenesulfones), poly(alkylenesulfones), polyurethanes, poly(vinyl alcohols), polyacrylonitriles, polymethyl methacrylates, and copolymers thereof, the solvating polymer being optionally crosslinked. In another embodiment, the lithium salt of the solid electrolyte layer is selected from lithium hexafluorophosphate (LiPFe), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), 2-trifluoromethyl-4,Lithium 5-dicyanoimidazolate (LiTDI), lithium 4,5-dicyano-1,2,3-triazolate (LiDCTA), lithium bis(pentafluoroethylsulfonyl)imide (LiBETI), lithium tetrafluoroborate (UBF4), lithium bis(oxalato)borate (LiBOB), lithium nitrate (UNO3), lithium chloride (LiCl), lithium bromide (LiBr), lithium fluoride (LiF), lithium perchlorate (UCIO4), lithium hexafluoroarsenate (LiAsFe), lithium trifluoromethanesulfonate (USO3CF3) (LiTf), lithium fluoroalkylphosphate Li[PF3(CF2CF3)3] (LiFAP), lithium tetrakis(trifluoroacetoxy)borate Li[B(OCOCF3)4] (LiTFAB), lithium bis(1,2- lithium benzenediolato(2-)-O,O')borate Li[B(CeO2)2] (LBBB), and a combination thereof.,

[0035] According to another embodiment, the solid electrolyte further comprises a ceramic.

[0036] According to a third aspect, the present technology relates to an electrochemical cell comprising a negative electrode and a positive electrode, in which:

[0037] (a) the negative electrode comprises a negative electrode film comprising a first and a second surface, the first surface being optionally pretreated, wherein said negative electrode comprises a first thin layer comprising an inorganic compound in a solvating polymer and optionally an ionic salt and / or a plasticizer, the first thin layer being disposed on the first surface of the negative electrode film and having an average thickness of about 15 μm or less, the mass ratio of "inorganic compound:solvating polymer" in the first thin layer is in the range of about 1:20 to about 20:1; and

[0038] (b) the negative electrode comprises a second thin layer comprising a solvating polymer, an ionic salt and optionally a plasticizer, the second thin layer being disposed on the first thin layer and having an average thickness of about 15 μm or less, wherein the solvating polymer of the first layer is the same as or different from the solvating polymer of the second layer; and / or the positive electrode comprises a film of positive electrode material comprising a positive electrode electrochemically active material, optionally a binder, and optionally an electronically conductive material, the film of positive electrode material comprising a first and a second surface, the first surface facing the negative electrode and carrying a third thin layer comprising a solvating polymer, an ionic salt, the third thin layer having an average thickness of about 50 μm or less;in which the electrochemical cell excludes the presence of an additional solid polymer electrolyte layer.;

[0039] In one embodiment, the electrochemical cell comprises the second thin layer, wherein the solvating polymer of the second thin layer is crosslinked or non-crosslinked. In another embodiment, the electrochemical cell comprises the third thin layer, wherein the solvating polymer of the third thin layer is crosslinked or non-crosslinked. In one example, the electrochemical cell comprises the second thin layer and the third thin layer.

[0040] In one embodiment, the solvating polymer of the first thin layer is crosslinked. In an alternative embodiment, the solvating polymer of the first thin layer is uncrosslinked.

[0041] In one embodiment, the negative electrode film is a current collector, for example comprising an electron-conducting solid support, such as a metal foil or grid (such as copper, nickel, etc.), a carbon or carbon-comprising film (such as carbon paper, self-supporting graphene, etc.), or other solid support (polymer, glass, etc.) comprising an electron-conducting layer (such as a current collector print).

[0042] In another embodiment, the negative electrode film comprises a metal film, for example comprising lithium or an alloy comprising lithium. In one embodiment, the metal film comprises lithium comprising less than 1000 ppm (or less than 0.1% by mass) of impurities.In another embodiment, the metal film comprises an alloy of lithium and an element selected from alkali metals other than lithium (such as Na, K, Rb, and Cs), alkaline earth metals (such as Mg, Ca, Sr, and Ba), rare earth metals (such as Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu), zirconium, copper, silver, bismuth, cobalt, manganese, zinc, aluminum, silicon, tin, antimony, cadmium, mercury, lead, molybdenum, iron, boron, indium, thallium, nickel, and germanium (e.g., Zr, Cu, Ag, Bi, Co, Zn, Al, Si, Sn, Sb, Cd, Hg, Pb, Mn, B, In, Tl, Ni, or Ge), for example, the alloy may comprise at least 75% by mass of lithium, or between 85% and 99.9% lithium by mass.

[0043] In one embodiment, the negative electrode film further comprises a pretreatment layer on the first surface, the latter being in contact with the first thin layer. According to one embodiment, the pretreatment layer comprises a compound selected from a silane, a phosphonate, a borate, an organic salt or compound, a carbon (such as graphite, graphene, etc.), an inorganic salt or compound (such as LiF, U3N, U3P, UNO3, U3PO4, etc.), or a thin layer of an element different from the metal of the metal film or forming an alloy therewith at the surface (such as an element defined above), said pretreatment layer having an average thickness of less than 5 pm, or less than 3 pm, or less than 1 pm, or less than 500 nm, or less than 200 nm, or less than 100 nm, or even less than 50 nm. In another embodiment, the first surface of the negative electrode film is pretreated by stamping.

[0044] In another embodiment, the inorganic compound is in the form of particles (e.g., spherical, rod-shaped, needle-shaped, etc.), for example, with an average size of less than 1 pm, less than 500nm, or less than 300nm, or less than 200nm, or between 1nm and 500nm, or between 10nm and 500nm, or between 50nm and 500nm, or between 100nm and 500nm, or between 1nm and 300nm, or between 10nm and 300nm, or between 1nm and 200nm, or between 10nm and 200nm, or between 50nm and 200nm, or between 100nm and 200nm, or between 1nm and 100nm, or between 10nm and 100nm, or between 25nm and 100nm, or between 50nm and 100nm.

[0045] In one embodiment, the inorganic compound comprises a ceramic. In another embodiment, the inorganic compound is selected from AI2O3, Mg2B20s, Na2O-2B2O3, xMgO yB2O3-zH2O, TiO2, ZrO2, ZnO, Ti20s, SiO2, Cr20s, CeO2, B2O3, B2O, SrBi4Ti40i5, LLTO, LLZO, LAGP, LATP, Fe2O3, BaTiOs, Y-UAIO2, a metal / carbon mixture (such as Sn+C, Zn+C, Ni2P+C), molecular sieves and zeolites (e.g., aluminosilicate, mesoporous silica), sulfide ceramics (such as U7P3S11), glass-ceramics (such as LIPON, etc.), and other ceramics, as well as combinations thereof.

[0046] In another embodiment, the particles of the inorganic compound further comprise organic groups covalently grafted to their surface, for example, said groups being chosen from crosslinkable groups (such as organic groups comprising acrylate, methacrylate, vinyl, glycidyl, mercapto, etc. functions), aryl groups, alkylene oxide or poly(alkylene oxide) groups, and other organic groups, or one of their combinations, optionally comprising a spacer group between the organic groups and the particles of the inorganic compound. In one embodiment, the grafted organic groups comprise poly(alkylene oxide) chains attached to the particles of the inorganic compound by a spacer group.For example, the spacer group may be selected from silane or halogenated silane, phosphonate, carboxylate, catechol, (meth)acrylate or poly(meth)acrylate, alkylene or polyalkylene groups, and combinations thereof.

[0047] According to one embodiment, the particles of the inorganic compound have a small specific surface area (e.g., less than 80 m 2 / g, or less than 40 m 2 / g). According to another embodiment, the mass ratio "inorganic compound:solvating polymer" in the first thin layer is in the range of about 2:5 to about 4:1, or about 2:5 to about 2:1, or about 1:2 to about 2:1, or about 4:5 to about 2:1, or about 1:1 to about 2:1, or about 4:5 to about 3:2. In another embodiment, the particles of the inorganic compound have a large specific surface area (e.g., 80 m 2 / g and more, or 120 m 2 / g and above). In yet another embodiment, the mass ratio of "inorganic compound:solvating polymer" in the first thin layer is in the range of about 1:20 to about 2:1, or about 2:5 to about 2:1, or about 2:5 to about 6:5, or about 1:20 to about 6:5, or about 2:5 to about 1:1, or about 1:20 to about 1:1, or about 2:5 to about 4:5, or about 1:20 to about 4:5.

[0048] According to one embodiment, the average thickness of the first thin layer is between about 0.5 pm and about 15 pm, or between about 1 pm and about 15 pm, or between about 1 pm and about 12 pm, or between about 0.5 pm and about 10 pm, or between about 1 pm and about 10 pm, or between about 2 pm and about 8 pm, or between about 2 pm and about 7 pm, or between 2 pm and about 5 pm.

[0049] According to another embodiment, the average thickness of the second thin layer is between about 50nm and about 15pm, or between about 0.1pm and about 15pm, between about 0.5pm and about 15pm, or between about 1pm and about 15pm, or between about 1pm and about 12pm, or between about 0.5pm and about 10pm, or between about 1pm and about 10pm, or between about 2pm and about 8pm, or between about 2pm and about 7pm, or between 2pm and about 5pm, or between 50nm and about 5pm, or between about 0.1pm and about 2pm.

[0050] In yet another embodiment, the second thin layer is present and the total average thickness of the first and second thin layers is in the range of about 1 pm to about 30 pm, or about 1 pm to about 25 pm, or about 5 pm to about 25 pm, or about 1 pm to about 20 pm, or about 1 pm to about 16 pm, or about 2 pm to about 12 pm, or about 3 pm to about 15 pm, or about 3 pm to about 12 pm, or about 4 pm to about 15 pm, or about 4 pm to about 12 pm.

[0051] In one embodiment, the average thickness of the third thin layer is about 40 pm or less, or about 30 pm or less, or about 15 pm or less, or between about 0.5 pm and about 50 pm, or between about 5 pm and about 50 pm, or between about 5 pm and about 40 pm, or between about 0.5 pm and about 15 pm, or between about 1 pm and about 15 pm, or between about 1 pm and about 12 pm, or between about 0.5 pm and about 10 pm, or between about 1 pm and about 10 pm, or between about 2 pm and about 8 pm, or between about 2 pm and about 7 pm, or between 2 pm and about 5 pm.

[0052] In yet another embodiment, the second thin layer and the third thin layer are present and the total average thickness of the first, second, and third thin layers is in the range of about 3 pm to about 60 pm, or about 10 pm to about 50 pm, or about 15 pm to about 30 pm, or about 3 pm to about 30 pm, or about 3 pm to about 25 pm, or about 5 pm to about 25 pm, or about 5 pm to about 20 pm, or about 8 pm to about 15 pm, or about 8 pm to about 12 pm, or about 5 pm to about 15 pm, or about 5 pm to about 12 pm, or about 5 pm to about 15 pm, or about 9 pm to about 15 pm.According to one embodiment, the solvating polymer is independently selected from linear or branched polyether polymers (e.g., PEO, PPO, or EO / PO copolymer), poly(dimethylsiloxanes), poly(alkylene carbonates), poly(alkylene sulfones), poly(alkylene sulfamides), polyurethanes, poly(vinyl alcohols), polyacrylonitriles, polymethyl methacrylates, and copolymers thereof, optionally comprising crosslinked units originating from crosslinkable functions (such as acrylate, methacrylate, vinyl, glycidyl, mercapto functions, etc.).

[0053] According to another embodiment, at least one of the first and second thin layers further comprises a plasticizer, or the first thin layer and the second thin layer further comprise a plasticizer, and / or the third thin layer further comprises a plasticizer. In one embodiment, the plasticizer is selected from glycol diether liquids (such as tetraethylene glycol dimethyl ether (TEGDME)), carbonate esters (such as propylene carbonate, ethylene carbonate, fluoroethylene carbonate), lactones (such as γ-butyrolactone), adiponitrile, ionic liquids and the like.

[0054] According to another embodiment, at least one of the first, second and third thin layers further comprises a lithium salt, or the first, second and third thin layers further comprise a lithium salt.In one embodiment, the lithium salt is selected from lithium hexafluorophosphate (LiPFe), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium 2-trifluoromethyl-4,5-dicyanoimidazolate (LiTDI), lithium 4,5-dicyano-1,2,3-triazolate (LiDCTA), lithium bis(pentafluoroethylsulfonyl)imide (LiBETI), lithium tetrafluoroborate (UBF4), lithium bis(oxalato)borate (LiBOB), lithium nitrate (UNO3), lithium chloride (LiCl), lithium bromide (LiBr), lithium fluoride (LiF), lithium perchlorate (UCIO4), lithium hexafluoroarsenate (LiAsFe), lithium trifluoromethanesulfonate (USO3CF3) (LiTf), lithium fluoroalkylphosphate Li[PF3(CF2CF3)3] (LiFAP), lithium tetrakis(trifluoroacetoxy)borate Li[B(OCOCF3)4] (LiTFAB), lithium bis(1,2-benzenediolato(2-)-O,O')borate Li[B(CeO2)2] (LBBB), and a combination thereof.

[0055] According to yet another embodiment, the negative electrode further comprises a current collector in contact with the second surface of the negative electrode film. In one embodiment, the positive electrode further comprises a current collector in contact with the second surface of the positive electrode material film.

[0056] In one embodiment, the positive electrode electrochemically active material is selected from metal phosphates, lithium metal phosphates, metal oxides, and lithium metal oxides. In another embodiment, the positive electrode electrochemically active material is LiM'PC t where M' is Fe, Ni, Mn, Co, or a combination thereof, LiVaOs, V2O5F, UV2O5, LiM^C t, LiM”C>2, where M” is Mn, Co, Ni, or a combination thereof (such as NMC, LiMn x Co y Neither zO2 with x+y+z = 1), Li(NiM'”)O2 (where M'” is Mn, Co, Al, Fe, Cr, Ti, Zr, or a combination thereof), elemental sulfur, elemental selenium, elemental iodine, iron(lll) fluoride, copper(lll) fluoride, lithium iodide, carbon-based active materials, organic cathode active materials (such as polyimide, poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate) (PTMA), tetralithium perylene-3,4,9,10-tetracarboxylate (PTCIJ4), naphthalene-1,4,5,8-tetracarboxylic dianhydride (NTCDA), perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA), TT-conjugated dicarboxylates, and anthraquinone), or a combination of two or more of these materials if compatible with each other. In another embodiment, the electrochemically active positive electrode material is in the form of optionally coated particles (e.g., polymer, ceramic, carbon, or a combination of two or more thereof).

[0057] According to a fourth aspect, the present technology relates to an electrochemical accumulator comprising at least one electrochemical cell as defined above. According to one embodiment, the electrochemical accumulator is a lithium battery or a lithium-ion battery.

[0058] According to a fifth aspect, the present technology relates to the use of an electrochemical accumulator as defined above, in a portable device, an electric or hybrid vehicle, or in the storage of renewable energy. According to one embodiment, the portable device is chosen from mobile phones, cameras, tablets and laptops. BRIEF DESCRIPTION OF THE FIGURES

[0059] Figure 1 shows (a) the X-ray diffractogram and (b) a scanning microscope image of Ni2P powder (Nii2Ps phase) obtained according to Example 1(a).

[0060] Figure 2 shows (a) the thermogravimetric curves of AI2O3 ( — ) and ALOa-polymer ( — ) powders, and (b) a photograph of a lithium strip with a 1 pm thin layer of Polymer 1 + AhCh-polymer ceramic according to Example 1(b).

[0061] Figure 3 shows the conductivity measurements between 20°C and 80°C on stainless steel of the polymer films A1 to A5 described in Example 2(a).

[0062] Figure 4 schematically illustrates different cell configurations comprising a polymer + inorganic compound layer on the anode and (a) a polymer electrolyte; (b) a polymer layer on the cathode and a polymer electrolyte, (c) a second layer without an inorganic compound on the polymer + inorganic compound layer and a polymer electrolyte; (d) a second layer without an inorganic compound on the polymer + inorganic compound layer (without polymer electrolyte); (e) a polymer layer on the cathode (without polymer electrolyte); and (f) a second layer without an inorganic compound on the polymer + inorganic compound layer, a polymer layer on the cathode (without polymer electrolyte).

[0063] Figure 5 shows the results (a) of galvanostatic cycling obtained at 50 °C and in C / 6 (2 cycles in C / 12 every 20 cycles in C / 6) for LFP / polymer electrolyte / Li batteries assembled with lithium without modification (reference) and lithiums having layers B1(i) to B3(i) according to Example 3(a); and (b) the representation of the capacity drop during cycling for the same batteries.

[0064] Figure 6 shows the results of (a) galvanostatic cycling obtained at 50 °C and C / 6 (2 cycles in C / 12 every 20 cycles in C / 6) for LFP / polymer electrolyte / Li batteries assembled with unmodified lithium (reference) and lithiums having layers B1 to B3 according to Example 3(b); and (b) the representation of the capacity drop during cycling for the same batteries.

[0065] Figure 7 shows the results (a) of galvanostatic cycling obtained at 50 °C and in C / 6 (2 cycles in C / 12 every 20 cycles in C / 6) for LFP / polymer electrolyte / Li batteries assembled with lithium without modification (reference) and lithiums having layers B1 to B3 according to Example 3(c) (with solid percentages of 17, 21 and 24%); and (b) the representation of the capacity drop during cycling for the same batteries.

[0066] Figure 8 shows the data of (a) galvanostatic cycling and (b) coulombic efficiencies obtained at 50 °C and C / 3 for LFP / polymer electrolyte / Li batteries assembled with unmodified lithium (reference) and lithium having a 4 pm layer of Polymer 1 with 130% ALCh-polymer (C1 cells according to Example 3(d)). The schematic represents the assembly of C1 cells.

[0067] Figure 9 shows the data of (a) galvanostatic cycling and (b) coulombic efficiencies obtained at 50 °C and in C / 3 for LFP / polymer electrolyte / Li batteries assembled with the unmodified lithium (reference) and a lithium having a 4 pm layer of Polymer 1 with 130% ALOa-polymer and an LFP cathode having a 2 or 4 pm Polymer layer (cells C2-a and C2-b according to Example 3(d)). The schematic represents the assembly of cells C2-a and C2-b.

[0068] Figure 10 shows the data of (a) galvanostatic cycling and (b) coulombic efficiencies obtained at 50 °C and C / 3 for LFP / polymer electrolyte / Li batteries assembled with the unmodified lithium (reference) and a lithium having a 4 pm layer of Polymer 1 with 130% ALCh-polymer and a second 4 pm layer of Polymer 1 (cell C3 according to Example 3(d)). The schematic represents the assembly of cell C3.

[0069] Figure 11 shows the data of (a) galvanostatic cycling and (b) coulombic efficiencies obtained at 50 °C and in C / 3 for LFP / polymer electrolyte / Li batteries assembled with the unmodified lithium (reference) and a lithium having a 4 pm layer of Polymer 1 with 130% ALCh-polymer and a second 9 or 12 pm layer of Polymer 1 without polymer electrolyte (cells C4-a and C4-b according to Example 3(d)). The schematic represents the assembly of cells C4-a and C4-b.

[0070] Figure 12 shows the data of (a) galvanostatic cycling and (b) coulombic efficiencies obtained at 50 °C and in C / 3 for LFP / polymer electrolyte / Li batteries assembled with the unmodified lithium (reference) and a lithium having a 4 pm layer of Polymer 1 with 130% ALOa-polymer and an LFP cathode having a 5, 8 or 11 pm polymer layer without polymer electrolyte (cells C5-a, C5-b, and C-5-c according to Example 3(d)). The schematic represents the assembly of cells C5-a, C5-b, and C-5-c.

[0071] Figure 13 shows the data of (a) galvanostatic cycling and (b) coulombic efficiencies obtained at 50 °C and in C / 3 for LFP / polymer electrolyte / Li batteries assembled with the unmodified lithium (reference) and a lithium having a 4 pm layer of Polymer 1 with 130% ALCh-polymer and a second 3 or 4 pm layer of Polymer 1 as well as an LFP cathode having a 4 pm polymer layer, without polymer electrolyte (cells C6-a and C6-b according to Example 3(d)). The schematic represents the assembly of cells C6-a and C6-b.

[0072] Figure 14 shows the galvanostatic cycling obtained at 50 °C and in C / 3 for LFP / polymer electrolyte / Li batteries assembled with lithium without modification (reference), then with a lithium having a 5 pm layer of polymer 1 with 30% Ni2P and 17% carbon according to Example 3(e).

[0073] Figure 15 shows the data of (a) cycling stability (discharge capacity), (b) average voltage and (c) coulombic efficiencies obtained during galvanostatic cycling at 50 °C and in C / 3 for two LFP / polymer electrolyte / Li batteries assembled with lithium without modification (reference) and two C7 cells as described in Example 4.

[0074] Figure 16 shows the data of (a) cycling stability (discharge capacity), and (b) coulombic efficiencies obtained during galvanostatic cycling at 50 °C and in C / 3 for two LFP / polymer electrolyte / Li batteries assembled with the unmodified lithium (reference) and three C8 cells as described in Example 4.

[0075] Figure 17 shows the data of (a) discharge capacity, and (b) coulombic efficiencies obtained during cycling at 50 °C at rates ranging from C / 6 to 1C for an LFP / polymer electrolyte / Li battery assembled with the unmodified lithium (reference) and two C9 cells as described in Example 4.

[0076] Figure 18 shows the galvanostatic cycling obtained at 50 °C in C / 3 (a) and in C / 6 (b) for LFP / polymer electrolyte / Li batteries assembled with unmodified lithium (reference), and with lithiums modified with (a) an inorganic molecule (PCh) and (b) a thin layer of metal (Zn) according to Example 5. Figure 19 shows photographs of lithium strips having received (a) a treatment with PCI3 and (b) a treatment with PCI3 followed by a deposition of polymer 1 + AI2O3- polymer according to Example 5.

[0077] DETAILED DESCRIPTION

[0078] All technical and scientific terms and expressions used herein have the same meaning as generally understood by a person skilled in the art of the present technology. Definitions of certain terms and expressions used are nevertheless provided below.

[0079] When the term "about" is used here, it means approximately, in the region of, and around. When the term "about" is used in relation to a numerical value, it may vary it, for example, above and below its nominal value by a variation of 10%. This term may also take into account, for example, the experimental error specific to a measuring device or the rounding of a value.

[0080] Where a range of values ​​is referred to in this application, the lower and upper bounds of the range are, unless otherwise indicated, always included in the definition. For example, "between x and y", or "from x to y", means an interval in which the bounds x and y are included unless otherwise indicated. For example, the range "between 1 and 50" includes, inter alia, the values ​​1 and 50.

[0081] The chemical structures described here are drawn according to the conventions of the field. Also, when an atom, such as a carbon atom, as drawn appears to include an incomplete valence, then it will be assumed that the valence is satisfied by one or more hydrogen atoms even if they are not explicitly drawn.

[0082] As used herein, the term "alkyl" refers to saturated hydrocarbon groups having from 1 to 20 carbon atoms, including straight or branched alkyl groups. Non-limiting examples of alkyl groups may include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, isopropyl, tert-butyl, sec-butyl, isobutyl, and the like. Similarly, an "alkylene" group refers to an alkyl group located between two other groups. Examples of alkylene groups include methylene, ethylene, propylene, and the like. The terms "C1-C n alkyl" and "Ci-C n "alkylene" refers to an alkyl or alkylene group having from 1 to the number "n" of carbon atoms.

[0083] The present document therefore describes the surface modification of an electrode film as well as the electrodes comprising this modified electrode film. More specifically, the surface of the electrode film is modified by a stack of at least two thin layers, each about 15 μm or less in thickness.

[0084] According to one example, this electrode film may be made of a metal film, for example comprising an alkali metal (such as lithium) or an alloy comprising predominantly an alkali metal (such as lithium).

[0085] In another example, the electrode film is a current collector, for example comprising an electron-conducting solid support, such as a metal foil or grid (such as copper, nickel, etc.), a carbon film or comprising carbon (such as carbon paper, self-supporting graphene, etc.), or other solid support (polymer, glass, etc.) comprising an electron-conducting layer (such as a current collector print). This may, for example, be lithiated during the first charge and discharge cycles. This lithiation process then generally occurs on the surface of the electron-conducting solid support or inside the meshes for a grid, or inside a pretreatment layer, in either case, the lithiation occurs on the surface of the electron-conducting solid support in contact with the first thin layer.

[0086] In this case, by surface modification is meant the application of a succession of two thin ion-conducting layers serving as a barrier to the formation of dendrites without, however, reacting substantially with the surface of the electrode film, the elements of the thin layers being predominantly non-reactive.

[0087] The surface of the electrode film is modified by applying to one of its surfaces a first thin layer comprising an inorganic compound in a solvating polymer, optionally comprising an ionic salt and / or a plasticizer. The first thin layer has an average thickness of about 15 μm or less. The inorganic compound is present in the first thin layer in a mass ratio of "inorganic compound:solvating polymer" in the first thin layer ranging from about 1:20 to about 20:1. The solvating polymer of the first layer may or may not be crosslinked. The second thin layer comprises a solvating polymer, an ionic salt and optionally a plasticizer, the second thin layer being disposed on the first thin layer and having an average thickness of about 15 μm or less. The solvating polymer of the first layer is the same as or different from the solvating polymer of the second layer.

[0088] The inorganic compound is preferably in the form of particles (e.g., spherical, rod-shaped, needle-shaped, etc.). The average particle size is preferably nanometric, for example, less than 1 pm, less than 500nm, or less than 300nm, or less than 200nm, or between 1 nm and 500nm, or between 10nm and 500nm, or between 50nm and 500nm, or between 10nm and 500nm, or between 10nm and 300nm, or between 50nm and 300nm, or between 100nm and 300nm, or between 1 nm and 200nm, or between 10nm and 200nm, or between 50nm and 200nm, or between 100nm and 200nm, or between 1nm and 100nm, or between 10nm and 100nm, or between 25nm and 100nm, or between 50nm and 100nm.

[0089] Non-limiting examples of inorganic compounds include AI2O3, Mg2B20s, Na2O-2B2O3, xMgO yB2O3 zH2O, TiO2, ZrO2, ZnO, Ti2O3, SiO2, Cr20s, CeO2, B2O3, B2O, SrBi4Ti40i5, LLTO, LLZO, LAGP, LATP, Fe2C>3, BaTiCh, y-LiAICh, a metal / carbon mixture (such as Sn+C, Zn+C, Ni2P+C), molecular sieve or zeolite (e.g., aluminosilicate, mesoporous silica), sulfide ceramic (such as U7P3S11), glass ceramic (such as LIPON, etc.), and other ceramics, as well as combinations thereof.

[0090] The surface of the particles of the inorganic compound may also be modified by organic groups covalently grafted to their surface. For example, the groups may be chosen from crosslinkable groups (such as organic groups comprising acrylate, methacrylate, vinyl, glycidyl, mercapto, etc. functions), aryl groups, alkylene oxide or poly(alkylene oxide) groups, and other organic groups, or one of their combinations, optionally comprising a spacer group between the organic groups and the particles of the inorganic compound. According to one example, the grafted organic groups comprise poly(alkylene oxide) chains attached to the particles of the inorganic compound by a spacer group.

[0091] According to other examples, the crosslinkable groups may comprise silane or halogenated silane, phosphonate, carboxylate, catechol, (meth)acrylate or poly(meth)acrylate, alkylene or polyalkylene functions, and combinations thereof. Scheme 1 shows an example of a method for grafting silanes comprising propyl methacrylate groups.

[0092] Diagram 1

[0093] In this example, the methacrylate group present on the propylsilane function can then be reacted with compatible groups, for example, to form a polymer chain such as a polyether. An example of this type of reaction will be shown below in Scheme 3.

[0094] In some cases, the particles of the inorganic compound have a small specific surface area (e.g., less than 80 m 2 / g, or less than 40 m 2 / g). The concentration of inorganic compound in the first thin layer may then be relatively high. For example, the mass ratio "inorganic compound: solvating polymer" in the first thin layer may be in the range of about 2:5 to about 4:1, or about 2:5 to about 2:1, or about 1:2 to about 2:1, or about 4:5 to about 2:1, or about 1:1 to about 2:1, or about 4:5 to about 3:2.

[0095] In other cases, the particles of the inorganic compound have a large specific surface area (e.g., 80 m 2 / g and more, or 120 m 2 / g and above). The greater porosity of the inorganic compound may then require a greater amount of polymer and the concentration of the inorganic compound in the first thin layer will be lower. For example, the mass ratio "inorganic compound:solvating polymer" in the first thin layer may then be in the range of about 1:20 to about 2:1, or about 2:5 to about 2:1, or about 2:5 to about 6:5, or about 1:20 to about 6:5, or about 2:5 to about 1:1, or about 1:20 to about 1:1, or about 2:5 to about 4:5, or about 1:20 to about 4:5.

[0096] As described above, the average thickness of the first and second thin layers is such that the latter is considered a modification of the electrode surface rather than an electrolyte layer. As mentioned above, the average thickness of the first thin layer and the second thin layer is less than 15 pm, respectively.

[0097] For example, for the first thin layer, the average thickness may be between about 0.5 pm and about 15 pm, or between about 1 pm and about 15 pm, or between about 1 pm and about 12 pm, or between about 0.5 pm and about 10 pm, or between about 1 pm and about 10 pm, or between about 2 pm and about 8 pm, or between about 2 pm and about 7 pm, or between 2 pm and about 5 pm.

[0098] As for the second thin layer, its average thickness may be between about 50nm and about 15pm, or between about 0.1pm and about 15pm, or between about 0.5pm and about 15pm, or between about 1pm and about 15pm, or between about 1pm and about 12pm, or between about 0.5pm and about 10pm, or between about 1pm and about 10pm, or between about 2pm and about 8pm, or between about 2pm and about 7pm, or between 2pm and about 5pm, or between 50nm and about 5pm, or between about 0.1pm and about 2pm.

[0099] For example, the total average thickness of the first and second thin layers may be in the range of about 1 pm to about 30 pm, or about 1 pm to about 25 pm, or about 5 pm to about 25 pm, or about 1 pm to about 20 pm, or about 1 pm to about 16 pm, or about 2 pm to about 12 pm, or about 3 pm to about 15 pm, or about 3 pm to about 12 pm, or about 4 pm to about 15 pm, or about 4 pm to about 12 pm.

[0100] The polymer present in the first and / or second layer is independently selected from polymers comprising solvating units of ions, in particular lithium ions. Examples of solvating polymers include linear or branched polyether polymers (e.g., PEO, PPO, or EO / PO copolymer), poly(dimethylsiloxanes), poly(alkylene carbonates), poly(alkylene sulfones), poly(alkylene sulfamides), polyurethanes, poly(vinyl alcohols), polyacrylonitriles, polymethyl methacrylates, and copolymers thereof, and optionally comprising crosslinked units originating from crosslinkable functions (such as acrylate, methacrylate, vinyl, glycidyl, mercapto functions, etc.).

[0101] In some examples, at least one of the first and second thin layers further comprises a plasticizer. The first thin layer and the second thin layer may each comprise a plasticizer. In some alternatives, only the first thin layer further comprises a plasticizer. The plasticizers used are those generally known to be compatible with electrochemical cells and cycling conditions. They generally comprise relatively high boiling organic liquids. Non-limiting examples of plasticizers include glycol diether liquids (such as tetraethylene glycol dimethyl ether (TEGDME)), carbonate esters (such as propylene carbonate, ethylene carbonate, fluoroethylene carbonate), lactones (such as γ-butyrolactone), adiponitrile, ionic liquids and the like.

[0102] According to a preferred example, at least one of the first and second thin layers further comprises a lithium salt, for example, both layers may comprise a lithium salt.Non-limiting examples of lithium salts include lithium hexafluorophosphate (LiPFe), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium 2-trifluoromethyl-4,5-dicyanoimidazolate (LiTDI), lithium 4,5-dicyano-1,2,3-triazolate (LiDCTA), lithium bis(pentafluoroethylsulfonyl)imide (LiBETI), lithium tetrafluoroborate (UBF4), lithium bis(oxalato)borate (LiBOB), lithium nitrate (UNO3), lithium chloride (LiCl), lithium bromide (LiBr), lithium fluoride (LiF), lithium perchlorate (LiCIC>4), lithium hexafluoroarsenate (LiAsFe), lithium trifluoromethanesulfonate (USO3CF3) (LiTf), lithium fluoroalkylphosphate Li[PF3(CF2CF3)3] (LiFAP), lithium tetrakis(trifluoroacetoxy)borate Li[B(OCOCF3)4] (LiTFAB), lithium bis(1,2-benzenediolato(2-)-O,O')borate Li[B(CeO2)2] (LBBB), or a combination of two or more of these.As mentioned above, the electrode film may comprise a metal film, which is preferably a film of lithium or an alloy comprising lithium, optionally on a current collector. When the metal film is a lithium film, it consists of lithium comprising less than 1000 ppm (or less than 0.1% by mass) of impurities. Alternatively, a lithium alloy may comprise at least 75% by mass of lithium, or between 85% and 99.9% by mass of lithium.The alloy may then comprise an element selected from alkali metals other than lithium (such as Na, K, Rb, and Cs), alkaline earth metals (such as Mg, Ca, Sr, and Ba), rare earth metals (such as Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu), zirconium, copper, silver, bismuth, cobalt, manganese, zinc, aluminum, silicon, tin, antimony, cadmium, mercury, lead, molybdenum, iron, boron, indium, thallium, nickel and germanium (e.g., Zr, Cu, Ag, Bi, Co, Zn, Al, Si, Sn, Sb, Cd, Hg, Pb, Mn, B, In, Tl, Ni, or Ge).

[0103] The electrode film may also include a pretreatment layer on the first surface, the latter being in contact with the first thin layer. For example, the pretreatment layer comprises a compound selected from a silane, a phosphonate, a borate, an organic salt or compound, a carbon (such as graphite, graphene, etc.), an inorganic salt or compound (such as LiF, U3N, U3P, UNO3, U3PO4, etc.), or a thin layer of an element different from a metal of the electrode film or forming an alloy with it on the surface (e.g., an element as defined above with reference to the possible alloys), said pretreatment layer having an average thickness of less than 1 μm, or less than 500 nm, or less than 200 nm, or less than 100 nm, or even less than 50 nm. The pretreatment layer is generally produced by contacting the first surface of the electrode film with an organic or inorganic compound according to known methods.For example, contacting a lithium film with PCI3 generally produces U3P and / or U3PO4. Similarly, applying a powder or a very thin film of a metallic element different from a metal of the electrode film, for example, chosen from the elements defined above may produce a thin layer of alloy.

[0104] For example, the pretreatment layer is formed on the electrode film before the addition of the first thin layer. The surface of the electrode film may also be treated before the application of the first thin layer, for example by stamping. In another example, the electrode comprises a current collector in contact with the second surface of the electrode film.

[0105] Electrochemical cells comprising the present surface-modified electrode are also contemplated. For example, such an electrochemical cell comprises a negative electrode and a positive electrode, wherein at least one of the negative electrode and the positive electrode is as defined herein and may be illustrated, for example, in Figures 4(c), (d) and (f). In a preferred example, the negative electrode is as defined herein and comprises an electrode film as defined above; and the positive electrode comprises a film of positive electrode material comprising a positive electrode electrochemically active material, optionally a binder, and optionally an electronically conductive material.

[0106] For example, the electrochemically active material of the positive electrode may be selected from metal phosphates, lithiated metal phosphates, metal oxides, and lithiated metal oxides, but also other materials such as sulfur, selenium or elemental iodine, iron(III) fluoride, copper(III) fluoride, lithium iodide, and carbon-based active materials. Examples of electrochemically active material of the positive electrode include LiM'PCL where M' is Fe, Ni, Mn, Co, or a combination thereof, LiVaOs, V2O5F, UV2O5, LiM^CL, LiM”C>2, where M” is Mn, Co, Ni, or a combination thereof (such as NMC, LiMn x Co y Neither zO2 withx+y+z = 1), Li(NiM'”)O2 (where M'” is Mn, Co, Al, Fe, Cr, Ti, Zr, or a combination thereof), elemental sulfur, elemental selenium, elemental iodine, iron(lll) fluoride, copper(lll) fluoride, lithium iodide, carbon-based active materials, organic cathode active materials such as polyimide, poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate) (PTMA), perylene-3,4,9,10-tetralithium tetracarboxylate (PTCU4), naphthalene-1,4,5,8-tetracarboxylic dianhydride (NTCDA), perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA), dicarboxylates TT-conjugates, and anthraquinone, or a combination of two or more of these materials when compatible with each other and with the negative electrode, for example a lithium electrode.The electrochemically active material of the positive electrode is preferably in the form of particles which may optionally be coated with, for example, polymer, ceramic, carbon or a combination of two or more thereof. Examples of electronically conductive materials which may be included in the electrode material include carbon black (such as Ketjen carbons. MC , Denka MC , Shawinigan, acetylene black, etc.) graphite, graphene, carbon nanotubes, carbon fibers (including carbon nanofibers, gas-formed carbon fibers (VGCF), etc.), non-powdery carbon obtained by carbonization of an organic precursor (for example, as a coating on particles), or a combination of two or more of these.

[0107] Non-limiting examples of electrode material binders include the polymer binders described above in connection with thin films or below for the electrolyte, but also rubber-type binders such as SBR (styrene-butadiene rubber), NBR (acrylonitrile-butadiene rubber), HNBR (hydrogenated NBR), CHR (epichlorohydrin rubber), and ACM (acrylate rubber), or fluoropolymer-type binders such as PVDF (polyvinylidene fluoride), PTFE (polytetrafluoroethylene), and combinations thereof. Some binders, such as rubber-type binders, may also include an additive such as CMC (carboxymethylcellulose).

[0108] Other additives may also be present in the electrode material, such as lithium salts or inorganic particles such as ceramic or glass, or other compatible active materials (e.g., sulfur).

[0109] In one example, the positive electrode material film comprises a first and a second surface, the first surface facing the negative electrode and carrying a third thin layer comprising a solvating polymer (e.g., as defined above), an ionic salt (e.g., as defined above), the third thin layer having an average thickness of about 50 pm or less, about 40 pm or less, or about 30 pm or less, or about 15 pm or less, or about 10 pm or less, or is between about 0.5 pm and about 50 pm, or between about 5 pm and about 50 pm, or between about 5 pm and about 40 pm, or between about 0.5 pm and about 15 pm, or between about 1 pm and about 15 pm, or between about 1 pm and about 12 pm, or between about 0.5 pm and about 10 pm, or between about 1 pm and about 10pm, or between about 2pm and about 8pm, or between about 2pm and about 7pm, or between 2pm and about 5pm.The third thin layer may also comprise a plasticizer, for example as defined above. The positive electrode material may be applied to a current collector (e.g., aluminum, copper). In one example, the current collector is carbon-coated aluminum.

[0110] In one example, the electrochemical cell excludes the presence of a solid polymer electrolyte layer, excluding, for example, an electrolyte layer with a thickness of more than 15 μm, or 20 μm or more. It is understood that the cell also does not include another type of electrolyte, for example, liquid or gel impregnating a separator.

[0111] Alternatively, the electrochemical cell further comprises a solid electrolyte layer comprising a polymer and a lithium salt. For example, the polymer of the electrolyte may be selected from linear or branched polyether polymers (e.g., PEO, PPO, or EO / PO copolymer), and optionally comprising crosslinkable units), poly(dimethylsiloxanes), poly(alkylene carbonates), poly(alkylene sulfones), poly(alkylene sulfamides), polyurethanes, poly(vinyl alcohols), polyacrylonitriles, polymethyl methacrylates, and copolymers thereof, the solvating polymer being optionally crosslinked. The lithium salt may be as defined above with reference to thin layers. The solid electrolyte may further comprise a ceramic.

[0112] According to an alternative embodiment, the present document also relates to an electrochemical cell comprising a negative electrode and a positive electrode, wherein the negative electrode comprises a negative electrode film and the positive electrode comprises a film of positive electrode material comprising an electrochemically active positive electrode material, optionally a binder, and optionally an electronically conductive material, and wherein:

[0113] (a) the negative electrode film comprises a first and a second surface, the first surface being optionally pretreated, wherein said negative electrode comprises a first thin layer comprising an inorganic compound in a solvating polymer and optionally an ionic salt and / or a plasticizer, the first thin layer being disposed on the first surface of the negative electrode film and having an average thickness of about 15 μm or less, the mass ratio of "inorganic compound:solvating polymer" in the first thin layer is in the range of about 1:20 to about 20:1;and (b) the negative electrode comprises a second thin layer comprising a solvating polymer, an ionic salt and optionally a plasticizer, the second thin layer being disposed on the first thin layer and having an average thickness of about 15 μm or less, wherein the solvating polymer of the first layer is the same as or different from the solvating polymer of the second layer; and / or the positive electrode material film comprises a first and a second surface, the first surface facing the negative electrode and carrying a third thin layer comprising a solvating polymer and an ionic salt, the third thin layer having an average thickness of about 50 μm or less, or about 15 μm or less;in which the electrochemical cell excludes the presence of an additional solid polymer electrolyte layer. The electrochemical cell also excludes any other type of additional electrolyte, thereby also excluding the use of liquid or gel type electrolytes, for example, impregnating a separator. Examples of such a cell are illustrated in Figures 4(d), (e) and (f).;

[0114] In one example, the electrochemical cell comprises the second thin layer. In another example, the electrochemical cell comprises the third thin layer. In yet another example, the electrochemical cell comprises the second and third thin layers.

[0115] The solvating polymer of each of the thin layers is independently as defined herein and may be independently crosslinked or uncrosslinked. In one example, the solvating polymer of at least one of the first, second, and third layers is uncrosslinked. In one example, the solvating polymer of the first layer is uncrosslinked. In another example, the solvating polymer of the second layer is uncrosslinked. The solvating polymer of each of the first, second, and third layers may be uncrosslinked. Or the polymer of the third layer is crosslinked and that of the first and second layers is uncrosslinked. Alternatively, the solvating polymer of each of the first, second, and third layers may be crosslinked.

[0116] As with the above electrode film, the negative electrode film of the present electrochemical cell may be a current collector, for example comprising an electron-conducting solid support, such as a metal foil or grid (such as copper, nickel, etc.), a carbon or carbon-comprising film (such as carbon paper, self-supporting graphene, etc.), or other solid support (polymer, glass, etc.) comprising an electron-conducting layer (such as a current collector print). Alternatively, the negative electrode film may comprise a metal film, for example comprising lithium or an alloy comprising lithium, wherein the lithium film and its alloys may also be defined as above. The present negative electrode film may also comprise a pretreatment layer as mentioned above.

[0117] The inorganic material of the first thin layer is as defined above and may be included in the same mass ratios described above.

[0118] The average thickness of the first thin layer may be between about 0.5 pm and about 15 pm, or between about 1 pm and about 15 pm, or between about 1 pm and about 12 pm, or between about 0.5 pm and about 10 pm, or between about 1 pm and about 10 pm, or between about 2 pm and about 8 pm, or between about 2 pm and about 7 pm, or between 2 pm and about 5 pm. The average thickness of the second thin layer may, for its part, be between approximately 50nm and approximately 15pm, or between approximately 0.1pm and approximately 15pm, between approximately 0.5pm and approximately 15pm, or between approximately 1pm and approximately 15pm, or between approximately 1pm and approximately 12pm, or between approximately 0.5pm and approximately 10pm, or between approximately 1pm and approximately 10pm, or between approximately 2pm and approximately 8pm, or between approximately 2pm and approximately 7pm, or between 2pm and approximately 5pm, or between 50nm and approximately 5pm, or between approximately 0.1pm and approximately 2pm.

[0119] In fact, when the second thin layer is present, the total average thickness of the first and second thin layers is preferably in the range of about 1 pm to about 30 pm, or about 1 pm to about 25 pm, or about 5 pm to about 25 pm, or about 1 pm to about 20 pm, or about 1 pm to about 16 pm, or about 2 pm to about 12 pm, or about 3 pm to about 15 pm, or about 3 pm to about 12 pm, or about 4 pm to about 15 pm, or about 4 pm to about 12 pm.

[0120] The average thickness of the third thin layer is about 40 pm or less, or about 30 pm or less, or about 15 pm or less, or between about 0.5 pm and about 50 pm, or between about 5 pm and about 50 pm, or between about 5 pm and about 40 pm, or about 0.5 pm and about 15 pm, or between about 1 pm and about 15 pm, or between about 1 pm and about 12 pm, or between about 0.5 pm and about 10 pm, or between about 1 pm and about 10 pm, or between about 2 pm and about 8 pm, or between about 2 pm and about 7 pm, or between 2 pm and about 5 pm.

[0121] It should be noted that when only one of the second and third thin layers is present, the present layer may have a slightly greater thickness. When both the second thin layer and the third thin layer are present, the latter may be thinner, and the total average thickness of the first, second, and third thin layers may be in the range of about 3 pm to about 60 pm, or about 10 pm to about 50 pm, or about 15 pm to about 30 pm, or about 3 pm to about 30 pm, or about 3 pm to about 25 pm, or about 5 pm to about 25 pm, or about 5 pm to about 20 pm, or about 8 pm to about 15 pm, or about 8 pm to about 12 pm, or about 5 pm to about 15 pm, or about 5 pm to about 12 pm, or about 5 pm to about 15 pm, or about 9 pm to about 15 pm.

[0122] In some examples, at least one of the first and second thin layers further comprises a plasticizer, preferably the first thin layer and the second thin layer further comprise a plasticizer. The third thin layer may also further comprise a plasticizer. The plasticizer is also as defined above. Similarly, at least one of the first, second and third thin layers may further comprise a lithium salt, preferably each of the three layers. The lithium salt is also as defined above.

[0123] The negative electrode may also further comprise a current collector in contact with the second surface of the negative electrode film. Similarly, the positive electrode may also further comprise a current collector in contact with the second surface of the positive electrode material film. The positive electrode material is also as defined with reference to the preceding electrochemical cell.

[0124] This document relates to an electrochemical accumulator comprising at least one electrochemical cell as defined herein. For example, the electrochemical accumulator is a lithium or lithium-ion battery.

[0125] In another aspect, the electrochemical accumulators of the present application are intended for use in portable devices, for example mobile phones, cameras, tablets or laptops, in electric or hybrid vehicles, or in the storage of renewable energy.

[0126] The present document also relates to a process for the preparation of a surface-modified electrode as described herein. This process comprises (i) mixing an inorganic compound and a solvating polymer in a solvent, optionally comprising a salt and / or a plasticizer; (ii) spreading the mixture obtained in (i) on the surface of the electrode; (iii) removing the solvent to obtain a first thin layer; (iv) mixing a solvating polymer and a salt in a solvent, optionally comprising a plasticizer; (v) spreading the mixture obtained in (iv) on the first thin layer obtained in (iii); and (vi) removing the solvent.

[0127] When steps (i) and / or (iv) further comprise a crosslinking agent, the method may further comprise a step of crosslinking the polymer (for example ionically, thermally or by irradiation), before, after or during steps (iii) and / or (vi), respectively.

[0128] When the electrode is a metal film such as lithium, steps (ii), (iii), (v), and / or (vi) are preferably carried out under vacuum, or in an anhydrous enclosure which can be filled with an inert gas such as argon.

[0129] Alternatively, where the polymer is crosslinkable and is sufficiently liquid prior to crosslinking, the process may exclude the presence of solvent and steps (iii) and / or (vi) may be avoided.

[0130] The mixing steps may be carried out by various methods used in the field of the present technology. For example, such methods may include planetary, ball, disc, ultrasonic (e.g., sonotrode) mixers, homogenizers (such as a rotor-stator type homogenizer), etc.

[0131] Spreading may be carried out by conventional methods, for example, using a roller, such as a rolling mill roller, coated with the mixture (including a continuous roll-to-roll processing method), by doctor blade, by spray coating, by centrifugation, by printing, etc.

[0132] The organic solvent used may be any solvent that is non-reactive with the electrode film, for example, non-reactive with lithium when the electrode film comprises metallic lithium. Examples include tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), heptane, toluene, or a combination thereof.

[0133] EXAMPLES

[0134] The following non-limiting examples are illustrative embodiments and should not be construed as further limiting the scope of the present invention. These examples will be better understood by referring to the accompanying figures.

[0135] Unless otherwise indicated, numbers expressing component quantities, preparatory conditions, concentrations, properties, etc. used herein should be interpreted as modified in each instance by the term "approximately." At a minimum, each numerical parameter should be interpreted in light of the number of significant figures reported and by the application of customary rounding techniques. Therefore, unless otherwise indicated, the numerical parameters mentioned herein are approximations that may vary depending on the properties sought. Nevertheless, although the parameters defining the broadest embodiments are approximations, the numerical values ​​presented in the following examples are reported as precisely as possible. Any numerical value, however, inherently contains a certain margin of error resulting from variations in experiments, measurements, statistical analyses, etc.

[0136] Example 1 - Synthesis and characterization of ceramics

[0137] (a) Synthesis of N12P and characterization

[0138] Ni2P nanoparticles are synthesized by liquid means using a vacuum ramp ("Schlenk line"), but could also be synthesized by other known means, for example, in solvothermal conditions under pressure using an autoclave.

[0139] In a 250 mL three-necked flask with a magnetic stir bar are added 0.9962 g of Ni(acac)2 and 20 mL of 1-octadecene. The mixture is stirred gently (500 RPM) and the temperature of the mixture is raised to 120 °C. The reaction mixture is then stirred at this temperature under vacuum for 30 minutes to remove volatile impurities and traces of water. The assembly is then purged with argon and is also bubbled for at least 5 minutes in the liquid. Then, 8 mL of tri-n-octylphosphine is introduced using a syringe through a septum. The mixture is then heated to 320 "C and left to react for 20 hours.

[0140] The mixture is then allowed to cool slowly to room temperature and then centrifuged at 10,000 rpm for 30 minutes in small 25 mL centrifuge tubes. The powder is easier to recover due to the absence of surfactant. The light brown supernatant is removed, the powder is redispersed in ethanol, and the resulting black liquid is centrifuged again. This step is repeated three more times. A black powder is obtained with a yield of nearly 90%.

[0141] Figure 1(a) shows the X-ray powder diffractogram of the obtained material. The peaks obtained are relatively broad and not very intense, which confirms a nanometric size of the Ni2P particles. There is only one phase obtained which is in fact a Ni^Ps phase. Figure 1(b) shows a scanning microscope image of the Ni^Ps powder. Only one phase is clearly visible and composed of small spherical particles with a diameter of about 20 nm.

[0142] (b) Synthesis of modified A^C (AC-polymer) and characterization

[0143] The attachment of a polymer to the surface of a ceramic is done in two steps. For the demonstration, an ALCh powder (needle shape, -164 m 2 / g) was used. First, a silanization reaction on the surface of the ALCh particles is carried out to attach crosslinkable groups. Diagram 2 shows this first step of surface modification.

[0144] Diagram 2 Approximately 10 g of AhCh powder is dispersed using an ultrasonic rod in 100 mL of toluene. The mixture is poured into a 250 mL glass flask equipped with an air condenser. The mixture is kept stirring and the assembly is purged with nitrogen for 10 min. Then, approximately 1 g of 3-(trimethoxysilyl)propyl methacrylate is added and the liquid is kept at 90 °C for 17 hours. Once the liquid has returned to room temperature, it is centrifuged using a 250 mL centrifuge tube (5000 RPM, 20 minutes). The resulting powder is cleaned 3 times with acetone by centrifugation and then dried at 140 °C under vacuum for at least 24 hours.

[0145] The second step consists of the polymerization of polyethylene glycol units on the surface of ALO particles. Scheme 3 shows the reaction protocol.

[0146] Diagram 3

[0147] The previously prepared modified powder is dispersed again in toluene using the same dispersion method. Nitrogen is bubbled through the liquid to remove traces of oxygen. Polyethylene glycol methacrylate (M n= 500 g / mol) is added in a proportion of 15% by mass relative to the alumina and then 0.5% by mass of azobisisobutyronitrile (AIBN) is added. The setup is equipped with an air cooler and a nitrogen flow is maintained throughout the reaction. The temperature is set at 80 °C for 17 hours. Once the liquid has returned to room temperature, it is centrifuged using a 250 mL centrifuge tube (5000 RPM, 20 minutes). The resulting powder is cleaned 3 times with acetone by centrifugation and then dried at 120 °C under vacuum for at least 24 h. This powder is called AhCh-polymer. Figure 2(a) shows the thermogravimetric curves of the AI2O3 ( — ) and ALOa-polymer ( — ) powders. The continuous mass loss between 200 and 600 °C for the modified powder allows us to determine that there is approximately 10% polymer in the final composite.Figure 2(b) shows an example of coating (1 pm thin layer) made on a lithium strip with an ink composed of Polymer 1 + ALOa-polymer. Polymer 1 refers to a polymer detailed in US Patent No. US 6,903,174 comprising crosslinkable groups.

[0148] Example 2 - Formulation of inks for electrode surface modification

[0149] (a) Polymer inks (without inorganic compound)

[0150] / . Polymer inks A 1-A5 (without inorganic compound) and conductivity tests

[0151] To increase the ionic conductivity of lithium deposits, a plasticizer, tetraethylene glycol dimethyl ether (TEGDME), is used. Inks were prepared according to the proportions indicated in Table 1 by mixing Polymer 1 with a lithium salt (LiTFSI), respecting a molar ratio O:Li = 20:1, and with different amounts of TEGDME (ranging from 8 to 40% relative to the mass of Polymer 1). A crosslinking agent, lrgacure-651 MC , was also added at a rate of 0.5% by mass relative to the mass of Polymer 1.

[0152] The depositions were carried out using a doctor blade on 50 μm thick stainless steel strips on a coating table. The strips were left under the fume hood for 5 minutes before being inserted into a nitrogen-flow box equipped with an ultraviolet (UV) lamp. After a 5-minute nitrogen purge, the films were crosslinked under UV light for 2 minutes.

[0153] These films are then assembled into a button cell and conductivity measurements are taken at different temperatures between 20 and 80 °C. Figure 3 shows the conductivity measurements recorded at different temperatures for the different films A1 to A5 above deposited on stainless steel. Compared to the A1 film of polymer 1 without TEGDME, almost an order of magnitude more conductivity is obtained after the addition of only 8% TEGDME. At 50 °C, a very good ionic conductivity of 1.02x10 -3 S / cm is obtained for A5 film with 40% TEGDME. The mechanical strength of the film is also very good despite the presence of 40% liquid (TEGDME). / / . A6 polymer ink (for coating on cathode)

[0154] In a plastic container compatible with a Thinky type planetary mixer, an adequate quantity of Polymer 1 is introduced with a quantity of LiTFSI salt adjusted to obtain an O:Li molar ratio of 20:1. An anhydrous solvent, tetrahydrofuran (THF) is added in sufficient quantity to obtain, after mixing, a solution with 18.5% solids (polymer + salt). The solution is mixed in the planetary mixer at 2000 RPM for 3 minutes. This mixing step is repeated seven times.

[0155] / / / . Polymer ink A 7 (for coating on cathode)

[0156] In a plastic container compatible with a Thinky type planetary mixer, an adequate quantity of Polymer 1 is introduced with a quantity of LiTFSI salt adjusted to obtain a molar ratio O:Li of 25:1. A mass of plasticizer (TEGDME) equivalent to 40% of the mass of polymer is added. A second anhydrous solvent, tetrahydrofuran (THF) is added in sufficient quantity to have, after mixing, a solution at 21% solid (polymer + salt + TEGDME). In this calculation, TEGDME is considered in the solids. Finally, 0.5% by mass relative to the polymer of I rgacure MC is added as a crosslinking agent. The solution is mixed in the planetary mixer at 2000 RPM for 3 times 10 minutes. iv. A8 polymer ink with plasticizer (for second layer coating)

[0157] For lithium coatings, it was chosen to use a slightly higher concentration of TEGDME, which amounts to 44% in polymer-inorganic compound films and polymer films, in order to promote the mixing of ceramic particles, adhesion and good conductivity of the deposited layers.

[0158] For the second coating on lithium, which does not contain ceramic, the polymer solution is prepared as follows. In a plastic container compatible with a Thinky type planetary mixer, an adequate quantity of Polymer 1 is introduced with a quantity of LiTFSI salt so as to obtain an O:Li molar ratio of 20:1. Then, 44% by mass of TEGDME relative to the polymer is added and the whole is mixed in the planetary mixer at 2000 RPM for three minutes. THF is added in sufficient quantity to obtain after mixing a solution at 18.1% solid (polymer + salt). The solution is mixed in the planetary mixer at 2000 RPM for 3 minutes. This mixing step is repeated six times. v. A9 polymer ink (for spray application in second layer)

[0159] In a glass bottle a precise quantity of Polymer 2 is added. Polymer 2 refers to a polymer detailed in US Patent No. US 6,903,174 but not including crosslinkable groups. A quantity of LiTFSI salt is added so as to obtain an O:Li molar ratio of 20:1. THF solvent is added so as to obtain a very dilute solution of salted polymer. Typically, a solution comprising 4% solids is obtained (salt + polymer). The solution is quickly homogeneous by simply mixing by hand.

[0160] Table 1. Composition of polymer inks and films a. Percentages are by weight relative to the mass of Polymer 1.

[0161] (b) Polymer-inorganic compound inks B 1-B5 (for anode coating)

[0162] / . Procedure 1 (B1-B3 with AC ceramic -polymer): In a plastic container compatible with a Thinky type planetary mixer, an adequate quantity of Polymer 1 is introduced with a quantity of LiTFSI salt in such a way as to obtain an O:Li molar ratio of 20:1. Then, 44% by mass of TEGDME relative to the polymer is added and the whole is mixed in the planetary mixer at 2000 RPM for three minutes. After 2 minutes of rest, a quantity of AI2O3 ceramic-polymer corresponding to a ratio of 56% to 130% of the mass of the polymer is added and the whole is mixed again for 3 minutes at 2000 RPM. This mixing step is repeated four times. The ink obtained, homogeneous and without agglomerates, is diluted with anhydrous THF in order to obtain a 17% solid solution (polymer + salt + ceramic). The solution is mixed twice for 3 minutes at 2000 RPM.

[0163] The compositions (excluding solvent) of inks B1 to B3 are described in Table 2. In some experiments, lrgacure MC (0.5% by mass relative to the polymer) was also added as a crosslinking agent. These compositions can then be designated B1 (i) to B3 (i), where (i) indicates the additional presence of lrgacure MC .

[0164] / / . Procedure 2 (B4 with metal / carbon mixture):

[0165] Further tests were carried out with metallic nanoscale particles of Sn or Zn as well as with a metallic phosphide Ni2P. A carbon black with spherical particles of about 75 nm in diameter and with a specific surface area of ​​about 45 m 2 / g is used. In a plastic container, an adequate amount of Polymer 1 is introduced with a sufficient amount of LiTFSI salt to obtain an O:Li molar ratio of 20:1. Then, 44% by mass of TEGDME relative to the polymer is added and the whole is mixed using a disk mixer (Ultra-Turrax® type) at 1000 RPM for 2 minutes until a uniform liquid is obtained. Then, an amount of Sn, Zn or Ni2P (of Ni^Ps phase prepared according to Example 1(a)) between 30 and 90% by mass relative to the polymer is introduced into the plastic container. Subsequently, 10% to 20% by mass of carbon is added. The whole is mixed with the disk mixer at 2500 RPM for 8 minutes. THF is added in sufficient quantity to obtain, after mixing, a 17% solid solution (polymer + salt + carbon + metal).Finally, after introducing the THF, the solution is mixed one last time with the disc mixer at 2500 RPM for 2 minutes.

[0166] The B4 ink shown in Table 2 is an example of an ink comprising a mixture of Ni2P and carbon.

[0167] / / / . Procedure 3 (B5-a and B5-b with AI2O3): In a plastic container, a certain amount of unmodified alumina (unsieved AKPG15 type) is mixed with THF using a sonotrode (50% power) for 4 minutes (Ink B5-a) or an IKA type rotor-stator homogenizer at maximum power for 10 min (Ink B5-b). During this time, a polymer solution is prepared. It contains an amount of Polymer 1 equivalent in mass to that of alumina, the LiTFSI salt is added so as to obtain an O:Li molar ratio of 20:1. A mass of plasticizer (TEGDME) equivalent to 100% of the polymer mass is added, without adding any crosslinking agent. The polymer solution is mixed in the planetary mixer at 2000 RPM for 3 times 10 minutes. Finally, the solution is poured into the plastic container containing the ceramic and THF solvent. The final solution contains approximately 21% solid (polymer + salt + ceramic + TEGDME).This is mixed one last time in a conical tube with a vortex before coating on the lithium.

[0168] Table 2. Composition of polymer inks and films a. Percentages are by weight relative to the mass of Polymer 1. b. Variation between B5-a and B5-b in the mixing method (see Example 2(b)(iii))

[0169] Example 3 - Surface-modified electrodes and electrochemical properties

[0170] Examples of cell configurations studied (according to the invention and as comparative) are shown in Figures 4(a) to 4(f). The cells in 4(a) to 4(c) are with polymer electrolyte, while the cells in Figures 4(d) to 4(f) are without polymer electrolyte. All lithiums used contain at least a first thin layer of inorganic compound in a polymer (represented as Polymer 1 + AI2O3- polymer). The cells in Figures 4(c), 4(d) and 4(f) comprise a second layer of Polymer 1 without ceramic and which is applied to the surface of the first layer. The cells in Figures 4(b), 4(e) and 4(f) comprise a layer of Polymer 1 with a lithium salt, but without ceramic or plasticizer on the cathode surface.

[0171] (a) Modified electrodes (one layer with crosslinking) (typical cell Fig. 4(a))

[0172] Button cells were assembled with an LFP cathode (8 mg / cm 2, composition: carbon-coated LFP: carbon black: Polymer 1: LiTFSI in proportions of about 73:1:19:7), lithiums with a layer of Polymer 1 + ALOs-polymer and a self-supporting film of branched polyethylene oxide electrolyte with allyl ether functions (25 μm thick) (hereinafter referred to as EPS). Polymer 1 + AhCh-polymer inks B1(i), B2(i) and B3(i) were prepared (see Example 2(b) and Table 2). Note that for this example, the films deposited on lithium were crosslinked (with 0.5% by mass of lrgacure MC ).

[0173] The coatings with these inks were carried out on the lithium surface using a doctor blade on a coating table with a speed of 10 mm / s. The lithiums were left for 5 minutes under the hood and then 5 minutes in an oven at 50 °C to evaporate the remaining THF. The films were then placed in a box under nitrogen flow equipped with a UV lamp. After 5 minutes of nitrogen purging, the films were crosslinked under UV light for 2 minutes. The thicknesses of the deposits were approximately 4 μm after the drying and crosslinking steps.

[0174] The typical assembly is as illustrated in Figure 4(a) (varying the AI2O3- polymer contents according to those of inks B1(i) to B3(i)). The assemblies are therefore made with three lithiums covered with a layer having different contents of polymer-modified ceramic. Figure 5(a) shows the galvanostatic cycling carried out in C / 6 at 50 °C for the different batteries as well as for the reference (LFP cathode and lithium anode without modification and self-supporting polymer electrolyte). Figure 5(b) is a representation of the capacity drop during cycling for the same batteries. Two cells are cycled per lithium and the cycles are relatively reproducible. Compared to the cycling for the reference battery, those for the batteries with the polymer + ceramic layer give higher discharge capacities. The greater the quantity of ceramic, the higher the capacity and the stable cycling.

[0175] (b) Modified electrodes (one layer without crosslinking) (typical cell Fig. 4(a))

[0176] The same deposits as previously (those of Example 3(a) above) without the addition of crosslinking agent (inks B1, B2 and B3) were carried out on lithium, but this time without crosslinking. In terms of electrochemical performance (see Figure 6), the conclusions are similar. The more ceramic the composition of the polymer layer contains, the higher the discharge capacity (Figure 6(a)) and the more stable the cycling (Figure 6(b)) over the cycles. Thus, for the following examples of coating on lithium, the percentage of ceramic was set at 130%. Also, the polymer layer in the following examples is not crosslinked. Beyond 130%, with this ceramic, the layer begins to lose mechanical properties, as it approaches a “ceramic polymer” type layer. Coating tests including double depositions of polymer layers on lithium were therefore also carried out.

[0177] (c) Modified electrodes (one layer without crosslinking) (typical cell Fig. 4(a))

[0178] Further coating tests were carried out keeping the amount of ALCh-polymer fixed at 130% (ink B3 according to Example 3(b)) and varying the percentage of solids in the inks between 17 and 24% depending on the amount of THF solvent added to the ink. The corresponding galvanostatic cycles obtained at 50 °C and C / 6 are shown in Figure 7(a) and the cycling stability is shown in Figure 7(b). It would appear that the higher the percentage of solids, the better the discharge capacity. There is very little difference between 21 and 24% solids. The capacity loss (Figure 7(b)) is very similar for each of the modified lithiums and the capacity retention is slightly better with 21% solids in the ink composition. However, to allow better dispersion of the ceramics in the ink, it is preferable to use solids levels around 17%.For the following examples (first layer on lithium with different fillers such as modified AI2O3, Sn + carbon, Zn + carbon), the solid rates with the different ceramics are therefore fixed at approximately 17%. (d) Typical cells of Figures 4(a) to 4(f) and comparative cycling (in C / 3).

[0179] Batteries corresponding to the representations in Figures 4(a) to 4(f) were prepared with the elements described in Table 3.

[0180] Table 3. Composition of batteries (elements in order) a a. “-” indicates absence of the element, layers A6, A8 and B3 are defined in Example 2. b. Composition of the LFP cathode defined in Example 3(a).

[0181] Figure 8 shows (a) the galvanostatic cycling and (b) the Coulombic efficiencies obtained at 50 °C and in C / 3 for LFP / polymer electrolyte / Li batteries assembled with unmodified lithium (reference) and a lithium having a 4 pm layer of Polymer 1 with 130% ALOa-polymer (cell C1). The polymer films are not crosslinked. Compared to the three reference cells, the two C1 cells with modified lithium have better reproducibility and do not show a progressive capacity gain over the first two cycles. The specific capacity in discharge is also slightly higher for the cells with modified lithium. Moreover, a better Coulombic efficiency (-99%) is obtained already in the second cycle for the cells assembled with lithium containing the ceramic layer while about 91-92% Coulombic efficiency is obtained for the reference cells.

[0182] Figure 9 shows (a) the galvanostatic cycling and (b) the coulombic efficiencies obtained at 50 °C and C / 3 for LFP / polymer electrolyte / Li batteries assembled with lithium and the unmodified LFP cathode (reference), then with lithium having a 4 pm layer of Polymer 1 with 130% ALOa-polymer and an LFP cathode having a 2 or 4 pm polymer layer (cells C2-a and C2-b, respectively). The polymer films are not crosslinked. The configuration for the assembly of the cells with modified lithium is shown in the inset in Figure 9(b). Compared to the assembly of the C1 cells, an LFP cathode with a thin polymer layer was used for the cells in Figure 9 (except for the references).The overall resistance of the cells was reduced by adding this polymer layer on the LFP cathode, as discharge capacities of approximately 112 and 115 mAh / g were obtained when 4 and 2 µm layers were deposited on the cathode surface, respectively. Without this added layer on the cathode, the discharge capacities were around 100 mAh / g (see Figure 8(a)). Again, the reproducibility is very good using polymer layers on lithium and cathode, as shown in the two cells cycled with the cathode having a 4 µm polymer layer. Coulombic efficiencies are also better for the cells with the modified cathodes and anodes. This gives approximately 77% coulombic efficiency in the first cycle when cathodes modified with a 2 or 4 pm polymer layer are used, while only 62 to 66% are obtained for the reference batteries.This experiment demonstrates that the thin polymer layers on the surface of the electrodes (anode and cathode) allow better bonding with the self-supporting polymer electrolyte, thus reducing interface resistances.

[0183] As mentioned above, the amount of ceramic in the polymer layer deposited on the lithium surface was set at 130%, because beyond this, the layer loses in mechanical strength, but also in bonding. Thus, a second sticky layer containing no ceramic, but only the polymer, the salt and the TEGDME is deposited on the surface of the first layer of Polymer 1 + AhCh-polymer to decrease the interfacial resistance between the anode and the polymer electrolyte. The polymer films are not crosslinked. Figure 10 presents (a) the galvanostatic cycling and (b) coulombic efficiencies obtained at 50 °C and in C / 3 for LFP / polymer electrolyte / Li batteries assembled with lithium without modification (reference), then with lithium having a first 4 pm layer of Polymer 1 with 130% of ALOs-polymer and a second 4 pm layer of Polymer 1 (cell C3). The inset image (Figure 10(b)) provides a better visualization of the two layers deposited on the lithium surface.The improvement of the interface between the self-supporting polymer electrolyte and the anode is clearly visible since an initial discharge capacity of 121 mAh / g was obtained while about 100 mAh / g was obtained with the C1 cells when only the ALOs-polymer layer was deposited on lithium (see cycling in Figure 8(a)). However, a progressive loss of capacity is observed. It is possible that the layer is not optimal in this case. The coulombic efficiency reaches 80% in the first cycle for the C3 cell cycled with lithium containing both polymer layers (62 to 66% for the reference cells).

[0184] To ensure the relevance of having a second sticky layer on the lithium surface, a particular cell assembly was used without adding a self-supporting electrolyte. The inset schematic in Figure 11(b) represents the tested assembly. A second layer of Polymer 1 with TEGDME was deposited on the lithium surface with relatively high thicknesses of 9 and 12 μm (cells C4-a and C4-b in Table 3, respectively). Figure 11 presents (a) the galvanostatic cycling and (b) coulombic efficiencies obtained at 50 °C and C / 3 for LFP / polymer electrolyte / Li batteries assembled with the lithium without modification (reference), and then for batteries C4-a and C4-b. The polymer films are not crosslinked. The capacity difference is enormous by removing the self-supporting polymer electrolyte which brings a lot of resistance and interface problems in the battery.The first cycle discharge capacity is about 145-149 mAh / g for batteries without polymer electrolyte versus 85-90 mAh / g for reference batteries. However, in this case, the interface between the cathode, which has surface defects, and the second layer of Polymer 1 deposited on the lithium surface is not optimal. Indeed, we can observe small variations in the discharge capacity (Figure 11(a)), but especially larger variations in the coulombic efficiencies (Figure 11(b)), typical of an interface problem. At this stage, the electrochemical results seem more stable with a thicker second polymer layer (12 pm versus 9 pm), but the determining factor remains the optimization of the interface between the surface of this polymer layer and the surface of the cathode.

[0185] To confirm that the interface between the polymer layer on the anode and the cathode surface is not optimal and is the cause of the variations in coulombic efficiencies, a layer of Polymer 1 without TEGDME was deposited on the cathode surface. The inset diagram in Figure 12(b) represents the tested assembly. Three different polymer layer thicknesses of 5, 8 and 11 µm were used (cells C5-a, C5-b and C5-c in Table 3, respectively). It should be noted that for these cells, there is only a layer of Polymer 1 + AhCh-polymer on the lithium surface. The polymer films are not crosslinked. Figure 12 presents (a) the galvanostatic cycling and (b) coulombic efficiencies obtained at 50 °C and C / 3 for these batteries as well as for the references for comparison.The electrochemical results are remarkable, the three batteries are very reproducible so that we see almost no difference in their cycling (Figure 12(a)). The initial specific capacity in discharge is about 145 mAh / g. A progressive drop in capacity is observed, but seems to stabilize as cycling progresses. Coulombic efficiencies close to 99% are obtained during the first cycle, which is much better than the 62 to 66% for the reference batteries. It is important to note that the thickness of the deposit on the cathode (5, 8 or 11 pm) does not influence the electrochemical cycling under the conditions tested.

[0186] Finally, a last series of tests is performed by reducing the thickness of the polymer layer on the cathode since it seems to have very little influence on the cycling stability. In addition, to promote cohesion between the cathode and the lithium anode, a second 3 or 4 pm 1 + TEGDME polymer layer was deposited on the lithium (cells C6-a and C6-b in Table 3, respectively). The polymer films are not crosslinked. The configuration of these cells is as shown in the inset of Figure 13(b). The galvanostatic cycling and coulombic efficiencies obtained at 50 °C and in C / 3 for these batteries as well as for the references are presented in Figures 13(a) and 13(b). The cycles are very similar to those obtained in Figure 12 and perfectly demonstrate the usefulness of deposition of thin layers directly on the surface of the cathode and the anode to avoid the need for a self-supporting polymer electrolyte.Additionally, in this battery configuration, the lithium has the AI2O3-rich polymer layer which helps stabilize the lithium.

[0187] (e) Modified electrodes (one layer without crosslinking) (typical cell Fig. 4(a))

[0188] As mentioned above in Procedure 2 of Example 2(b)(iii), fillers of inorganic compounds other than ALOs-polymer were also used. A carbon / metal (M) mixture was tested for the purpose of forming a Li-M alloy during the plating of lithium from the cathode to the lithium anode. Carbon is also present for the conduction of electrons in the polymer layer. As examples, two metals were tested (namely Sn and Zn) as well as a nickel phosphide Ni2P. Only one type of carbon was tested, but others could be used. Figure 14 shows the galvanostatic cycling obtained at 50 °C and in C / 3 for LFP / polymer electrolyte / Li batteries assembled with lithium without modification (reference), then with a lithium having a 5 pm layer of polymer 1 with 30% Ni2P and 17% carbon (layer B4 of Table 2). The polymer films are not crosslinked.This is a first result, but it confirms that the concept works. We see an increase in the initial capacity compared to the reference batteries. A progressive drop in capacity is however observable as the cycling progresses. This type of layer could benefit from a battery configuration such as those presented in Figures 4(d) to 4(f), particularly that of Figure 4(f) corresponding to the C6 (a or b) battery presented above where AhCh-polymer could be replaced by the present carbon / metal mixture.

[0189] Example 4 - Surface-modified electrodes with spray-applied second layer and electrochemical properties

[0190] Other cells according to the invention in a configuration as shown in Figure 4(f). The first thin layer of inorganic compound in a polymer, however, is formed of Polymer 1 and unmodified alumina (AI2O3). The second thin layer on the lithium is applied by spraying in a very thin layer and comprises Polymer 2 rather than Polymer 1 and does not comprise a plasticizer. The cells also comprise a layer of different thickness of Polymer 1 with a lithium salt and a plasticizer, but without ceramic on the cathode surface. Several cells were prepared for each to be tested in parallel.

[0191] (a) Manufacture of C7 to C9 Batteries

[0192] For the C7 battery, the procedure is as follows:

[0193] Cathode: The A7 ink prepared in Example 2 is applied with a doctor blade to the surface of an LFP cathode, as described in Example 3(a), so as to obtain a thickness of 40 μm after crosslinking. Once coated, the cathode is left under the fume hood for 5 minutes then in a sealed box under nitrogen for 5 minutes and then crosslinked under UV for 10 minutes.

[0194] Anode (first layer): The B5-a ink obtained in Example 2 is applied with a doctor blade to the surface of a lithium film. The coating is dried for 5 minutes under a hood and then for 5 minutes at 50°C in an oven before the next step. The thickness of the dry deposit is approximately 8-9 μm.

[0195] Anode (second layer): The solution obtained for Ink A9 as prepared in Example 2 is sprayed under a fume hood onto the surface of the first layer on lithium with an argon pressure of 60 psi at a distance of about 30 cm and making two passes over the surface of the Li. Finally, the modified lithium foil is dried for 5 minutes in a fume hood at 50°C. The layer thus formed is very thin (close to 1 pm), but could not be measured precisely.

[0196] The free surface of the polymer on the cathode is then applied to the polymer surface of the second layer present on the anode. The resulting multi-layer material is pressed together and sachet-type batteries are formed from this material.

[0197] The C8 cell is prepared as for the C7 cell, applying a 30 pm layer on the cathode rather than 40 pm. Ink B5-a is also replaced by Ink B5-b resulting in a layer thickness of about 7-8 pm.

[0198] The C9 cell is prepared in the same way as the C7 cell, where a 20 pm layer is used on the cathode rather than 40 pm.

[0199] Table 4. Composition of batteries (elements in order) a a. The composition of layers A7, A9 and B5(a and b) is defined in Example 2. b. Composition of the LFP cathode defined in Example 3(a). c. Ultrathin layer (thickness not measured)

[0200] (b) Electrochemical results for C7 to C9 Batteries

[0201] Figures 15 to 17 present the electrochemical results obtained during the cycling of Cells C7 to C9 in comparison with an LFP / polymer electrolyte / Li cell assembled with lithium without modification (reference). Figure 15(a) demonstrates that Cell C7 is more stable during cycling than the reference cell. This aspect is even more visible in Figure 15(c) where a marked decrease in the coulombic efficiency is observed around the 20 e cycle for the reference batteries while it remains stable for the C7 batteries. Figure 15(b) also shows a higher average voltage for the C7 batteries compared to the reference batteries.

[0202] Figures 16(a) and 16(b) present cycling stability and coulombic efficiency results for C8 cells that are relatively similar to those obtained for C7 cells.

[0203] Figure 17 shows the capacity rate results obtained with C9 batteries for 5 cycles at each of the cycling rates of C / 6, C / 4, C / 3, C / 2 and 1C. Moreover, greater stability can be observed for the C9 batteries compared to the reference battery, particularly with the increase in cycling rate.

[0204] Example 5 - Pretreated electrodes with modified surface and electrochemical properties

[0205] An organic, inorganic or metallic pretreatment of the surface of the metal electrode film (here lithium) can also be carried out in order to form a pretreatment layer which can consist of the formation of a passivation layer, the formation or deposition of a compound, an organic or inorganic salt, or an alloy with a metal different from that of the electrode film.

[0206] Examples of deposition of a Polymer 1 + AhCh-polymer layer (B3 ink) were performed on different lithium films that received pretreatment. Figure 18 shows the galvanostatic cycling obtained at 50 °C in C / 3 (a) and in C / 6 (b) for LFP / polymer electrolyte / Li batteries assembled with lithium without modification (reference), and with lithiums pretreated with (a) an inorganic molecule (PCh) and (b) a thin layer of metal (Zn). These lithiums have demonstrated that they can help stabilize the cycling. The goal is to have cumulative effects with the polymer + inorganic compound layer and possibly a second layer. Thus, a first pretreatment to passivate the lithium surface and increase the diffusion of lithium on its surface, followed by a deposition of anti-dendrite polymer and allowing bonding to the solid electrolyte (polymer or ceramic type) is recommended.Figure 19 shows photographs of lithium strips having received (a) treatment with PCh and (b) treatment with PCI3 followed by deposition of polymer 1 + ALCh-polymer. The first deposition with PCh is very uniform and gives a light brown color (see Figure 19(a)). The integrity and quality of this first deposition are not affected by the deposition of the polymer 1 + AI2O3-polymer layer as shown in Figure 19(b). Several modifications could be made to either of the embodiments described above without departing from the scope of the present invention as contemplated. The references, patents or scientific literature documents referred to herein are incorporated by reference in their entirety and for all purposes.

Claims

DEMANDS 1. Electrode comprising an electrode film modified by a first thin film and a second thin film, wherein: the electrode film comprises a first and a second surface, the first surface being optionally pretreated; the first thin film comprises an inorganic compound in a solvent polymer and optionally an ionic salt and / or a plasticizer, the first thin film being disposed on the first surface of the electrode film and having an average thickness of about 15 pm or less, the mass ratio "inorganic compound: solvent polymer" in the first thin film being in the range of about 1:20 to about 20:1; and the second thin film comprises a solvent polymer, an ionic salt and optionally a plasticizer, the second thin film being disposed on the first thin film and having an average thickness of about 15 pm or less;in which the solvating polymer of the first layer is identical or different from the solvating polymer of the second layer.; 2. The electrode of claim 1, in which the solvating polymer of the first thin layer is crosslinked, and / or the solvating polymer of the second thin layer is crosslinked.

3. The electrode of claim 1, wherein the solvating polymer of the first thin layer is non-crosslinked, and / or the solvating polymer of the second thin layer is non-crosslinked.

4. The electrode of any one of claims 1 to 3, wherein the electrode film is a current collector, for example comprising an electron-conducting solid support, such as a metallic foil or grid (such as copper, nickel, etc.), a carbon film or comprising carbon (such as carbon paper, self-supporting graphene, etc.), or other solid support (polymer, glass, etc.) comprising an electron-conducting layer (such as a current collector print). 52 5. The electrode of any one of claims 1 to 3, wherein the electrode film comprises a metallic film, for example comprising lithium or an alloy comprising lithium.

6. The electrode of claim 5, wherein the metallic film comprises lithium comprising less than 1000 ppm (or less than 0.1% by mass) of impurities.

7. The electrode of claim 5, wherein the metal film comprises an alloy of lithium and an element selected from alkali metals other than lithium (such as Na, K, Rb, and Cs), alkaline earth metals (such as Mg, Ca, Sr, and Ba), rare earth metals (such as Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu), zirconium, copper, silver, bismuth, cobalt, manganese, zinc, aluminum, silicon, tin, antimony, cadmium, mercury, lead, molybdenum, iron, boron, indium, thallium, nickel, and germanium (for example, Zr, Cu, Ag, Bi, Co, Zn, Al, Si, Sn, Sb, Cd, Hg, Pb, Mn, B, In, Tl, Ni, or Ge).

8. The electrode of claim 7, wherein the alloy comprises at least 75% by mass of lithium, or between 85% and 99.9% by mass of lithium.

9. The electrode of any one of claims 1 to 8, wherein the electrode film further comprises a pretreatment layer on the first surface, the latter being in contact with the first thin layer.

10. The electrode of claim 9, wherein the pretreatment layer comprises a compound selected from a silane, a phosphonate, a borate, a salt or an organic compound, a carbon (such as graphite, graphene, etc.), an inorganic salt or compound (such as LiF, U3N, U3P, LiNOs, U3PO4, etc.), or a thin layer of an element other than a metal of the electrode film or forming an alloy with it on the surface (such as an element defined in claim 7), said pretreatment layer having an average thickness of less than 5 pm.

11. The electrode of claim 9 or 10, wherein the pretreatment layer has an average thickness of less than 3 pm, or less than 1 pm, or less than 500 nm, or less than 200 nm, or less than 100 nm, or even less than 50 nm.

12. The electrode of any one of claims 1 to 11, wherein the first surface of the electrode film is pretreated by stamping. 53 13. The electrode of any one of claims 1 to 12, wherein the inorganic compound is in the form of particles (e.g., spherical, rod-shaped, needle-shaped, etc.).

14. The electrode of claim 13, wherein the average particle size is less than 1 pm, less than 500 nm, or less than 300 nm, or less than 200 nm, or between 1 nm and 500 nm, or between 10 nm and 500 nm, or between 50 nm and 500 nm, or between 100 nm and 500 nm, or between 1 nm and 300 nm, or between 10 nm and 300 nm, or between 50 nm and 300 nm, or between 100 nm and 300 nm, or between 1 nm and 200 nm, or between 10 nm and 200 nm, or between 50 nm and 200 nm, or between 100 nm and 200 nm, or between 1 nm and 100 nm, or between 10 nm and 100 nm, or between 25nm and 100nm, or between 50nm and 100nm.

15. The electrode of claim 13 or 14, wherein the inorganic compound comprises a ceramic.

16. The electrode of claim 13 or 14, wherein the inorganic compound is selected from Al2O3, Mg2B2Os, Na2O-2B2C>3, xMgO 62O3 ZH2O, TiU2, ZrU2, ZnO, Ti2U3, SiO2, Cr2O3, CeO2, B2O3, B2O, SrBi4Ti4Oi5, LLTO, LLZO, LAGP, LATP, Fe2O3, BaTiO3, y-UAIO2, a metal / carbon mixture (such as Sn+C, Zn+C, Ni2P+C), molecular sieves and zeolites (for example, aluminosilicate, mesoporous silica), sulfide ceramics (such as U7P3S11), glass-ceramics (such as LIPON, etc.), and other ceramics, as well as combinations thereof.

17. The electrode of any one of claims 13 to 16, wherein the particles of the inorganic compound further comprise organic groups covalently grafted to their surface, for example, said groups being selected from crosslinkable groups (such as organic groups comprising acrylate, methacrylate, vinyl, glycidyl, mercapto, etc. functions), aryl groups, alkylene oxide or poly(alkylene oxide) groups, and other organic groups, or any combination thereof, optionally comprising a spacer group between the organic groups and the particles of the inorganic compound.

18. The electrode of claim 17, wherein the grafted organic groups comprise poly(alkylene oxide) chains attached to the particles of the inorganic compound by a spacer group. 54 19. The electrode of claim 17 or 18, wherein the spacer group is selected from the silane or halogenated silane, phosphonate, carboxylate, catechol, (meth)acrylate or poly(meth)acrylate, alkylene or polyalkylene groups, and combinations thereof.

20. The electrode of any one of claims 13 to 19, wherein the particles of the inorganic compound have a small specific surface area (e.g., less than 80 m²) 2 / g, or less than 40 m 2 / g).

21. The electrode of any one of claims 13 to 20, wherein the mass ratio "inorganic compound: solvating polymer" in the first thin layer is in the range of about 2:5 to about 4:1, or about 2:5 to about 2:1, or about 1:2 to about 2:1, or about 4:5 to about 2:1, or about 1:1 to about 2:1, or about 4:5 to about 3:

2.

22. The electrode of any one of claims 13 to 19, wherein the particles of the inorganic compound have a large specific surface area (for example, 80 m²) 2 / g and more, or 120 m 2 / g and more).

23. The electrode of any one of claims 13 to 19 and 22, wherein the mass ratio "inorganic compound: solvating polymer" in the first thin layer is in the range of about 1:20 to about 2:1, or about 2:5 to about 2:1, about 2:5 to about 6:5, or about 1:20 to about 6:5, or about 2:5 to about 1:1, or about 1:20 to about 1:1, or about 2:5 to about 4:5, or about 1:20 to about 4:

5.

24. The electrode of any one of claims 1 to 23, wherein the average thickness of the first thin layer is between about 0.5pm and about 15pm, or between about 1pm and about 15pm, or between about 1pm and about 12pm, or between about 0.5pm and about 10pm, or between about 1pm and about 10pm, or between about 2pm and about 8pm, or between about 2pm and about 7pm, or between 2pm and about 5pm.

25. The electrode of any one of claims 1 to 24, wherein the average thickness of the second thin layer is between approximately 50nm and approximately 15pm, or between approximately 0.1pm and approximately 15pm, or between approximately 0.5pm and approximately 15pm, 55 or between about 1pm and about 15pm, or between about 1pm and about 12pm, or between about 0.5pm and about 10pm, or between about 1pm and about 10pm, or between about 2pm and about 8pm, or between about 2pm and about 7pm, or between 2pm and about 5pm, or between 50nm and about 5pm, or between about 0.1pm and about 2pm.

26. The electrode of any one of claims 1 to 25, wherein the total average thickness of the first and second thin layers is in the range of about 1 pm to about 30 pm, or about 1 pm to about 25 pm, or about 5 pm to about 25 pm, or about 1 pm to about 20 pm, or about 1 pm to about 16 pm, or about 2 pm to about 12 pm, or about 3 pm to about 15 pm, or about 3 pm to about 12 pm, or about 4 pm to about 15 pm, or about 4 pm to about 12 pm.

27. The electrode of any one of claims 1 to 26, wherein the solvating polymer is selected from linear or branched polyether polymers (e.g., PEO, PPO, or EO / PO copolymer), poly(dimethylsiloxanes), poly(alkylene carbonates), poly(alkylene sulfones), poly(alkylene sulfamides), polyurethanes, poly(vinyl alcohols), polyacrylonitril, polymethyl methacrylates, and their copolymers, optionally comprising crosslinked units from crosslinkable functions (such as acrylates, methacrylates, vinyls, glycidyls, mercapto, etc.).

28. The electrode of any one of claims 1 to 27, wherein at least one of the first and second thin layers further comprises a plasticizer.

29. The electrode of claim 28, wherein the first thin layer and the second thin layer further comprise a plasticizer.

30. The electrode of claim 28 or 29, wherein the plasticizer is selected from glycol diether type liquids (such as tetraethylene glycol dimethyl ether (TEGDME)), carbonate esters (such as propylene carbonate, ethylene carbonate, fluoroethylene carbonate), lactones (such as γ-butyrolactone), adiponitrile, ionic liquids and others like them.

31. The electrode of any one of claims 1 to 30, at least one of the first and second thin layers further comprises a lithium salt.

32. The electrode of claim 31, wherein the first thin layer and the second thin layer further comprise a lithium salt.

33. The electrode of claim 31 or 32, wherein the lithium salt is selected from lithium hexafluorophosphate (LiPFe), lithium bis(trifluoromethanesulfonyl)imidide (LiTFSI), lithium bis(fluorosulfonyl)imidide (LiFSI), lithium 2-trifluoromethyl-4,5-dicyanoimidazolate (LiTDI), lithium 4,5-dicyano-1,2,3-triazolate (LiDCTA), lithium bis(pentafluoroethylsulfonyl)imidide (LiBETI), lithium tetrafluoroborate (UBF4), lithium bis(oxalato)borate (LiBOB), lithium nitrate (UNO3), lithium chloride (LiCl), lithium bromide (LiBr), lithium fluoride (LiF), lithium perchlorate (LiCIC4), lithium hexafluoroarsenate (LiAsFe), lithium trifluoromethanesulfonate (USO3CF3) (LiTf), lithium fluoroalkylphosphate Li[PF3(CF2CF3)3] (LiFAP), lithium tetrakis(trifluoroacetoxy)borate Li[B(OCOCF3)4] (LiTFAB), lithium bis(1,2-benzenediolato(2-)-O,O')borate Li[B(CeO2)2] (LBBB),and a combination of these.

34. The electrode of any one of claims 1 to 33, further comprising a current collector in contact with the second surface of the electrode film.

35. Electrochemical cell comprising a negative electrode and a positive electrode, wherein at least one of the negative electrode and the positive electrode is such as defined in any one of claims 1 to 34.

36. Electrochemical cell of claim 35, wherein: the negative electrode is as defined in any one of claims 1 to 34; and the positive electrode comprises a film of positive electrode material comprising an electrochemically active positive electrode material, optionally a binder, and optionally an electronically conductive material.

37. Electrochemical cell of claim 36, wherein the electrochemically active positive electrode material is selected from metal phosphates, lithia metal phosphates, metal oxides, and lithia metal oxides.

38. Electrochemical cell of claim 36, wherein the electrochemically active material of the positive electrode is LiM'PCL where M' is Fe, Ni, Mn, Co, or a combination of these, LiVaOs, V2O5F, UV2O5, LiM^C t, LiM”C>2, where M” is Mn, Co, Ni, or a combination of these (such as NMC, LiMn x Co y Neither zO2 with x+y+z = 1), Li(NiM”')O2 (where M'” is Mn, Co, Al, Fe, Cr, Ti, Zr, or a combination thereof), elemental sulfur, elemental selenium, elemental iodine, iron(III) fluoride, copper(II) fluoride, lithium iodide, carbon-based active materials, organic cathode active materials (such as polyimide, poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl) methacrylate (PTMA), perylene-3,4,9,10-tetralithium tetracarboxylate (PTCU4), naphthalene-1,4,5,8-tetracarboxylic dianhydride (NTCDA), perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA), TT-conjugated dicarboxylates, and anthraquinone), or a combination of two or more of these materials if compatible with each other.

39. Electrochemical cell of any one of claims 36 to 38, wherein the electrochemically active positive electrode material is in the form of particles optionally coated (e.g., polymer, ceramic, carbon or a combination of two or more of these).

40. Electrochemical cell of any one of claims 36 to 39, wherein the positive electrode material film comprises a first and a second surface, the first surface facing the negative electrode and bearing a third thin layer comprising a solvating polymer and an ionic salt, the third thin layer having an average thickness of approximately 50 pm or less, approximately 40 pm or less, or approximately 30 pm or less, or approximately 15 pm or less, or is between approximately 0.5 pm and approximately 50 pm, or between approximately 5 pm and approximately 50 pm, or between approximately 5 pm and approximately 40 pm, or between approximately 0.5 pm and approximately 15 pm, or between approximately 1 pm and approximately 15 pm, or between approximately 1 pm and approximately 12 pm, or between approximately 0.5 pm and approximately 10 pm, or between approximately 1 pm and approximately 10 pm, or between approximately 2 pm and around 8pm, or between around 2pm and around 7pm, or between 2pm and around 5pm.

41. Electrochemical cell of claim 40, wherein the solvent polymer is as defined in claim 27.

42. Electrochemical cell of claim 40 or 41, wherein the salt is a lithium salt, for example, as defined in claim 33. 58 43. Electrochemical cell of any one of claims 40 to 42, wherein the third thin layer further comprises a plasticizer, for example, as defined in claim 30.

44. Electrochemical cell of any one of claims 35 to 43, which excludes the presence of a solid polymer electrolyte layer.

45. Electrochemical cell of any one of claims 35 to 43, further comprising a solid electrolyte layer comprising a polymer and a lithium salt.

46. ​​Electrochemical cell of claim 45, wherein the electrolyte polymer is selected from linear or branched polyether polymers (e.g., PEO, PPO, or EO / PO copolymer), and optionally comprising crosslinkable units), poly(dimethylsiloxanes), poly(alkylene carbonates), poly(alkylene sulfones), poly(alkylene sulfamides), polyurethanes, poly(vinyl alcohols), polyacrylonitriles, polymethyl methacrylates, and their copolymers, the solvating polymer optionally being crosslinked.

47. Electrochemical cell of claim 45 or 46, wherein the lithium salt is selected from lithium hexafluorophosphate (LiPFe), lithium bis(trifluoromethanesulfonyl)imidide (LiTFSI), lithium bis(fluorosulfonyl)imidide (LiFSI), lithium 2-trifluoromethyl-4,5-dicyanoimidazolate (LiTDI), lithium 4,5-dicyano-1,2,3-triazolate (LiDCTA), lithium bis(pentafluoroethylsulfonyl)imidide (LiBETI), lithium tetrafluoroborate (UBF4), lithium bis(oxalato)borate (LiBOB), lithium nitrate (UNO3), lithium chloride (LiCl), lithium bromide (LiBr), lithium fluoride (LiF), lithium perchlorate (UCIO4), lithium hexafluoroarsenate (LiAsFe), the lithium trifluoromethanesulfonate (USO3CF3) (LiTf), lithium fluoroalkylphosphate Li[PF3(CF2CF3)3] (LiFAP), lithium tetrakis(trifluoroacetoxy)borate Li[B(OCOCF3)4] (LiTFAB), lithium bis(1,2-benzenediolato(2-)-O,O')borate Li[B(CeO2)2] (LBBB),and a combination of these.

48. Electrochemical cell of any one of claims 45 to 47, wherein the solid electrolyte further comprises a ceramic. 59 49. Electrochemical cell comprising a negative electrode and a positive electrode, in which: (a) the negative electrode comprises a negative electrode film comprising a first and a second surface, the first surface being optionally pretreated, wherein said negative electrode comprises a first thin layer comprising an inorganic compound in a solvent polymer and optionally an ionic salt and / or a plasticizer, the first thin layer being disposed on the first surface of the negative electrode film and having an average thickness of about 15 pm or less, the mass ratio of "inorganic compound:solvent polymer" in the first thin layer being in the range of about 1:20 to about 20:1; and(b) the negative electrode comprises a second thin layer comprising a solvating polymer, an ionic salt and optionally a plasticizer, the second thin layer being disposed on the first thin layer and having an average thickness of about 15 pm or less, wherein the solvating polymer of the first layer is the same as or different from the solvating polymer of the second layer; and / or the positive electrode comprises a film of positive electrode material comprising an electrochemically active positive electrode material, optionally a binder, and optionally an electronically conductive material, the film of positive electrode material comprising a first and a second surface, the first surface facing the negative electrode and bearing a third thin layer comprising a solvating polymer, an ionic salt, the third thin layer having an average thickness of about 50 pm or less, or about 15 pm or less;in which the electrochemical cell excludes the presence of an additional solid polymer electrolyte layer.

50. Electrochemical cell of claim 49, which includes the second thin layer.

51. Electrochemical cell of claim 50, wherein the solvating polymer of the second thin layer is crosslinked. 60 52. Electrochemical cell of claim 50, wherein the solvating polymer of the second thin layer is non-crosslinked.

53. Electrochemical cell of claim 49 or 50, which includes the third thin layer.

54. Electrochemical cell of claim 53, wherein the solvating polymer of the third thin layer is crosslinked.

55. Electrochemical cell of claim 53, wherein the solvating polymer of the third thin layer is non-crosslinked.

56. Electrochemical cell of any one of claims 49 to 55, wherein the solvating polymer of the first thin layer is crosslinked.

57. Electrochemical cell of any one of claims 49 to 55, wherein the solvating polymer of the first thin layer is non-crosslinked.

58. Electrochemical cell of any one of claims 49 to 57, wherein the negative electrode film is a current collector, for example comprising an electron-conducting solid support, such as a metallic foil or grid (such as copper, nickel, etc.), a carbon film or comprising carbon (such as carbon paper, self-supporting graphene, etc.), or other solid support (polymer, glass, etc.) comprising an electron-conducting layer (such as a current collector print).

59. Electrochemical cell of any one of claims 49 to 57, wherein the negative electrode film comprises a metallic film, for example comprising lithium or an alloy comprising lithium.

60. Electrochemical cell of claim 59, wherein the metallic film comprises lithium comprising less than 1000 ppm (or less than 0.1% by mass) of impurities.

61. Electrochemical cell of claim 59, wherein the metal film comprises an alloy of lithium and an element selected from alkali metals other than lithium (such as Na, K, Rb, and Cs), alkaline earth metals (such as Mg, Ca, Sr, and Ba), rare earth metals (such as Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, 61 Yb, Lu), zirconium, copper, silver, bismuth, cobalt, manganese, zinc, aluminum, silicon, tin, antimony, cadmium, mercury, lead, molybdenum, iron, boron, indium, thallium, nickel and germanium (e.g., Zr, Cu, Ag, Bi, Co, Zn, Al, Si, Sn, Sb, Cd, Hg, Pb, Mn, B, In, Tl, Ni, or Ge).

62. Electrochemical cell of claim 61, wherein the alloy comprises at least 75% by mass of lithium, or between 85% and 99.9% by mass of lithium.

63. Electrochemical cell of any one of claims 49 to 62, wherein the negative electrode film further comprises a pretreatment layer on the first surface, the latter being in contact with the first thin layer.

64. Electrochemical cell of claim 63, wherein the pretreatment layer comprises a compound selected from a silane, a phosphonate, a borate, a salt or an organic compound, a carbon (such as graphite, graphene, etc.), an inorganic salt or compound (such as Li F, U3N, U3, UNO3, U3PO4, etc.), or a thin layer of an element other than a metal of the negative electrode film or forming an alloy with it on the surface (such as an element defined in claim 55), said pretreatment layer having an average thickness of less than 5 pm.

65. Electrochemical cell of claim 57 or 58, wherein the pretreatment layer has an average thickness of less than 3 pm, or less than 1 pm, or less than 500 nm, or less than 200 nm, or less than 100 nm, or even less than 50 nm.

66. Electrochemical cell of any one of claims 49 to 65, wherein the first surface of the negative electrode film is pretreated by stamping. Q7. Electrochemical cell of any one of claims 49 to 66, wherein the inorganic compound is in the form of particles (e.g., spherical, rod-shaped, needle-shaped, etc.).

68. Electrochemical cell of claim 67, wherein the average particle size is less than 1 pm, less than 500 nm, or less than 300 nm, or less than 200 nm, or between 1 nm and 500 nm, or between 10 nm and 500 nm, or between 50 nm and 500 nm, or between 100 nm and 500 nm, or between 1 nm and 300 nm, or between 10 nm and 300 nm, or 62 between 50nm and 300nm, or between 10nm and 300nm, or between 1nm and 200nm, or between 10nm and 200nm, or between 50nm and 200nm, or between 100nm and 200nm, or between 1nm and 100nm, or between 10nm and 100nm, or between 25nm and 100nm, or between 50nm and 100nm.

69. Electrochemical cell of claim 67 or 68, wherein the inorganic compound comprises a ceramic.

70. Electrochemical cell of claim 67 or 68, wherein the inorganic compound is selected from Al2O3, Mg2B2Os, Na2O-2B2C>3, xMgO yB2C>3 zH2O, TiC>2, ZrC>2, ZnO, Ti2O3, SiO2, Cr2O3, CeO2, B2O3, B2O, SrBi4Ti4Oi5, LLTO, LLZO, LAGP, LATP, Fe2O3, BaTiOs, Y-LiAIC>2, a metal / carbon mixture (such as Sn+C, Zn+C, Ni2P+C), molecular sieves and zeolites (e.g., aluminosilicate, mesoporous silica), sulfide ceramics (such as U7P3S11), glass-ceramics (such as LIPON, etc.), and other ceramics, as well as combinations thereof.

71. Electrochemical cell of any one of claims 67 to 70, wherein the particles of the inorganic compound further comprise organic groups covalently grafted to their surface, for example, said groups being selected from crosslinkable groups (such as organic groups comprising acrylate, methacrylate, vinyl, glycidyl, mercapto, etc. functions), aryl groups, alkylene oxide or poly(alkylene oxide) groups, and other organic groups, or any combination thereof, optionally comprising a spacer group between the organic groups and the particles of the inorganic compound.

72. Electrochemical cell of claim 71, wherein the grafted organic groups comprise poly(alkylene oxide) chains attached to the particles of the inorganic compound by a spacer group.

73. Electrochemical cell of claim 71 or 72, wherein the spacer group is selected from the silane or halogenated silane, phosphonate, carboxylate, catechol, (meth)acrylate or poly(meth)acrylate, alkylene or polyalkylene groups, and combinations thereof. 63 74. Electrochemical cell of any one of claims 67 to 73, wherein the particles of the inorganic compound have a small specific surface area (e.g., less than 80 m²) 2 / g, or less than 40 m 2 / g).

75. Electrochemical cell of any one of claims 67 to 74, wherein the mass ratio "inorganic compound: solvating polymer" in the first thin layer is in the range of about 2:5 to about 4:1, or about 2:5 to about 2:1, or about 1:2 to about 2:1, or about 4:5 to about 2:1, or about 1:1 to about 2:1, or about 4:5 to about 3:

2.

76. Electrochemical cell of any one of claims 67 to 73, wherein the particles of the inorganic compound have a large specific surface area (e.g., 80 m²) 2 / g and more, or 120 m 2 / g and more).

77. Electrochemical cell of any one of claims 67 to 73 and 76, wherein the mass ratio "inorganic compound: solvating polymer" in the first thin layer is in the range of about 1:20 to about 2:1, or about 2:5 to about 2:1, about 2:5 to about 6:5, or about 1:20 to about 6:5, or about 2:5 to about 1:1, or about 1:20 to about 1:1, or about 2:5 to about 4:5, or about 1:20 to about 4:

5.

78. Electrochemical cell of any one of claims 49 to 77, wherein the average thickness of the first thin layer is between about 0.5pm and about 15pm, or between about 1pm and about 15pm, or between about 1pm and about 12pm, or between about 0.5pm and about 10pm, or between about 1pm and about 10pm, or between about 2pm and about 8pm, or between about 2pm and about 7pm, or between 2pm and about 5pm.

79. Electrochemical cell of any one of claims 49 to 78, wherein the average thickness of the second thin layer is between about 50nm and about 15pm, or between about 0.1pm and about 15pm, between about 0.5pm and about 15pm, or between about 1pm and about 15pm, or between about 1pm and about 12pm, or between about 0.5pm and about 10pm, or between about 1pm and about 10pm, or between about 2pm and about 8pm, or between about 2pm and about 7pm, or between 2pm and about 5pm, or between 50nm and about 5pm, or between about 0.1pm and about 2pm. 64 80. Electrochemical cell of any one of claims 49 to 79, wherein the second thin layer is present and the total average thickness of the first and second thin layers is in the range of about 1 pm to about 30 pm, or about 1 pm to about 25 pm, or about 5 pm to about 25 pm, or about 1 pm to about 20 pm, or about 1 pm to about 16 pm, or about 2 pm to about 12 pm, or about 3 pm to about 15 pm, or about 3 pm to about 12 pm, or about 4 pm to about 15 pm, or about 4 pm to about 12 pm.

81. Electrochemical cell of any one of claims 49 to 80, wherein the average thickness of the third thin layer is about 40 pm or less, or about 30 pm or less, or about 15 pm or less, or is between about 0.5 pm and about 50 pm, or between about 5 pm and about 50 pm, or between about 5 pm and about 40 pm, or between about 0.5 pm and about 15 pm, or between about 1 pm and about 15 pm, or between about 1 pm and about 12 pm, or between about 0.5 pm and about 10 pm, or between about 1 pm and about 10 pm, or between about 2 pm and about 8 pm, or between about 2 pm and about 7 pm, or between 2 pm and about 5 pm.

82. Electrochemical cell of any one of claims 49 to 81, wherein the second thin layer and the third thin layer are present and the total average thickness of the first, second and third thin layers is in the range of about 3pm to about 60pm, or about 10pm to about 50pm, or about 15pm to about 30pm, or about 3pm to about 30pm, or about 3pm to about 25pm, or about 5pm to about 25pm, or about 5pm to about 20pm, or about 8pm to about 15pm, or about 8pm to about 12pm, or about 5pm to about 15pm, or about 5pm to about 12pm, or about 5pm to about 15pm, or about 9pm to about 15pm.

83. Electrochemical cell of any one of claims 49 to 82, wherein the solvating polymer is independently selected from linear or branched polyether polymers (e.g., PEO, PPO, or EO / PO copolymer), poly(dimethylsiloxanes), poly(alkylene carbonates), poly(alkylene sulfones), poly(alkylene sulfamides), polyurethanes, poly(vinyl alcohols), polyacrylonitril, polymethyl methacrylates, and their copolymers, optionally comprising crosslinked units from crosslinkable functions (such as acrylate, methacrylate, vinyl, glycidyl, mercapto, etc. functions). 65 84. Electrochemical cell of any one of claims 49 to 83, wherein at least one of the first and second thin layers further comprises a plasticizer.

85. Electrochemical cell of claim 84, wherein the first thin layer and the second thin layer further comprise a plasticizer.

86. Electrochemical cell of any one of claims 49 to 85, wherein the third thin layer further comprises a plasticizer.

87. Electrochemical cell of any one of claims 84 to 86, wherein the plasticizer is selected from glycol diether type liquids (such as tetraethylene glycol dimethyl ether (TEGDME)), carbonate esters (such as propylene carbonate, ethylene carbonate, fluoroethylene carbonate), lactones (such as γ-butyrolactone), adiponitrile, ionic liquids and others like them.

88. Electrochemical cell of any one of claims 49 to 87, at least one of the first, second and third thin layers further comprises a lithium salt.

89. Electrochemical cell of claim 88, wherein the first, second and third thin layers further comprise a lithium salt.

90. Electrochemical cell of claim 88 or 89, wherein the lithium salt is selected from lithium hexafluorophosphate (LiPFe), lithium bis(trifluoromethanesulfonyl)imidide (LiTFSI), lithium bis(fluorosulfonyl)imidide (LiFSI), lithium 2-trifluoromethyl-4,5-dicyanoimidazolate (LiTDI), lithium 4,5-dicyano-1,2,3-triazolate (LiDCTA), lithium bis(pentafluoroethylsulfonyl)imidide (LiBETI), lithium tetrafluoroborate (UBF4), lithium bis(oxalato)borate (LiBOB), lithium nitrate (UNO3), lithium chloride (LiCl), lithium bromide (LiBr), lithium fluoride (LiF), lithium perchlorate (LiCIC), lithium hexafluoroarsenate (LiAsF6), lithium trifluoromethanesulfonate (USO3CF3) (LiTf), lithium fluoroalkylphosphate Li[PF3(CF2CF3)3] (LiFAP), lithium tetrakis(trifluoroacetoxy)borate Li[B(OCOCF3)4] (LiTFAB), lithium bis(1,2-benzenediolato(2-)-O,O')borate Li[B(CeO2)2] (LBBB),and a combination of these. 66 91. Electrochemical cell of any one of claims 49 to 90, wherein the negative electrode further comprises a current collector in contact with the second surface of the negative electrode film.

92. Electrochemical cell of any one of claims 49 to 91, wherein the positive electrode further comprises a current collector in contact with the second surface of the positive electrode material film.

93. Electrochemical cell of any one of claims 49 to 92, wherein the electrochemically active positive electrode material is selected from metal phosphates, lithia metal phosphates, metal oxides, and lithia metal oxides.

94. Electrochemical cell of any one of claims 49 to 92, wherein the electrochemically active positive electrode material is LiM'PC t where M' is Fe, Ni, Mn, Co, or a combination thereof, LiVaOs, V2O5F, UV2O5, LiM^C t, LiM”C>2, where M” is Mn, Co, Ni, or a combination thereof (such as NMC, LiMn x Co y Neither zO2 with x+y+z = 1), Li(NiM'”)O2 (where M'” is Mn, Co, Al, Fe, Cr, Ti, Zr, or a combination thereof), elemental sulfur, elemental selenium, elemental iodine, iron(III) fluoride, copper(II) fluoride, lithium iodide, carbon-based active materials, organic cathode active materials (such as polyimide, poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl) methacrylate (PTMA), perylene-3,4,9,10-tetralithium tetracarboxylate (PTCU4), naphthalene-1,4,5,8-tetracarboxylic dianhydride (NTCDA), perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA), TT-conjugated dicarboxylates, and anthraquinone), or a combination of two or more of these materials if compatible with each other.

95. Electrochemical cell of any one of claims 49 to 94, wherein the electrochemically active positive electrode material is in the form of particles optionally coated (e.g., polymer, ceramic, carbon or a combination of two or more of these).

96. Electrochemical accumulator comprising at least one electrochemical cell as defined in any one of claims 34 to 95. 67 97. Electrochemical accumulator of claim 96, wherein said electrochemical accumulator is a lithium battery or a lithium-ion battery.

98. Use of an electrochemical accumulator of claim 96 or 97, in a portable device, an electric or hybrid vehicle, or in renewable energy storage.

99. Use of claim 98, wherein the mobile device is selected from mobile phones, cameras, tablets and laptops. 68

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