Interlayer-expanded cathode materials for metal-carbon fluoride batteries

Abstract

A layered carbon fluoride (CFx) material is proposed in which polymer strands, oligomers or small organic molecules are intercalated between the layers of CFx and covalently bind to CFx. The resulting intercalated CFx material, when applied as a cathode active species, allows for a very fast cation transport and for the realization of simultaneous high energy and high power during the discharge of metal-CFx batteries.

Description

DESCRIPTION

[0001] The present application takes full benefit of US provisional patent application 63 / 580995, filed on Sept 7, 2023, entitled “Optimized Cathode Materials for Metal-Carbon Fluoride Batteries” by Karoly Nemeth, to the extent allowed by law.FIELD OF THE INVENTION

[0002] The present invention relates to interlayer-expanded 2D materials and their application as electro-active species in electrochemical energy storage devices. More specifically, the present invention proposes the intercalation of layered carbon fluoride (CFX) materials by polymers, oligomers and small molecules that are capable of covalendy binding to CFX. The resulting interlayer-expanded structures allow for an increased speed of transport of cations in said CFXmaterial as compared to the pristine (non-intercalated) CFX. The proposed intercalated CFXmaterial is thereby capable to achieve simultaneous high energy and high power densities during the discharge of the electrochemical energy storage device.BRIEF DESCRIPTION OF THE DRAWINGS

[0003] Figure 1 depicts the schematic view of the cross section of a polymer intercalated layered 2D material. The individual layers (rectangles) are separated by polymers (circles). In the present invention, the layers are monolayers of carbon fluoride (CFX) while the polymer may be polyacrylonitrile (PAN) or other. Alternatively, the circles may also represent small or medium size organic molecules which are capable to intercalate CFX.

[0004] Figure 2 depicts the covalent bonds between a cyano-polymerized polyaciylonitrile (PAN) (above the dashed line) and the carbon atom connectivity network of a fully fluorinated CFXlayer (below the dashed line). The C-F bonds are not shown. This is the optimal configuration for the PAN-functionalized intercalated CFX. The free-standing fluoride ions counterbalance the charge of the polymeric chain.

[0005] Figure 3 is a schematic representation of the cross section of a battery cell with the proposed intercalated CFXcathode active material. Elements of the cell include: (1) the anode (negative electrode) current collector, (2) the anode containing a reactive metal, (3) an ionic conductor which electronically isolates the anode from the cathode while ionically connects them, (4) the cathode (positive electrode), (5) the cathode current collector and (6) the intercalated CFXparticles as embedded in and being part of the cathode. The ionic conductor may be a porous plastic sheet filled with liquid electrolyte in which case both the anode and the cathode is in contact with the same liquid electrolyte. Alternatively, the ionic conductor may be one or more solid ion conductor, such as Li3PS4. A I M solution of LiBF4in a 1 :1 :1 volumetric mixture of propylene carbonate (PC), 1,2 dimethoxy ethane (DME) and 1,3-dioxalane (DOL) solvents is one example of an effective liquid electrolyte. The anode and the cathode is capable for both electronic and ionic conduction. One typical anode is a Li metal foil while one typicalcathode is a composite of 80 weight % CFX(with x=l), 10 % carbon black conductive additive and 10 % polymeric binder such as polyacrylonitrile.BACKGROUND OF THE INVENTION

[0006] Simultaneous high energy and high power density is very desirable for batteries in electric cars and other means of transportation. High energy density allows for long transportation range while high power density allows for the quick availability of energy at any time. For example, electric vertical take-off and landing aircraft (eVTOL) requires a large amount of energy in a short time for lifting itself and its payload up to a high altitude on a vertical trajectory. At the current state of the art, batteries used in electric cars neither have the the energy nor the power density required for electric aircrafts, especially for eVTOLs as discussed in the following reviews: Yang, X.G. et al: “Challenges and key requirements of batteries for electric vertical takeoff and landing aircraft”, Joule 2021, 5, 1644-1659; Bills, A. et al: “Performance metrics required of next-generation batteries to electrify commercial aircraft”, ACS Energy Lett. 2020, 5, 663-668; Krause, F. et al: “Performance of commercial Li-ion cells for future NASA missions and aerospace applications”, J. Electrochem. Soc. 2021, 168, 040504; and Krause, F.C. et al: “High specific energy lithium primary batteries as power sources for deep space exploration”, J. Electrochem. Soc. 2018, 165, A2312.

[0007] Additional reviews on this topic can be found in published white papers, such as [8] Argonne National Laboratory: “Assessment of the R&D Needs for Electric Aviation, White Paper”, (Sep 7, 2021); and J.T. Doo et al: “NASA Electric Vertical Takeoff and Landing (eVTOL) Aircraft Technology for Public Services - A White Paper” (Aug 1, 2021).

[0008] According to the performance metrics analysis provided in the above studies, only nextgeneration chemistries, like Li-air or Li-CFX, may be able to meet some of the requirements needed for electric commercial aircraft to achieve the range and payloads required for adoption.

[0009] While Li-air batteries are still in the basic research phase, Li-CFXbatteries have been a commercial reality since the 1970-es and they have been widely adopted, especially in military and space applications for their far superior and extremely large energy density as discussed in Brady et al: "Soldier-Portable Battery Supply: Foreign Dependence and Policy Options." (2014).

[0010] Lithium-carbon fluoride (Li-CFX) primary batteries have been commercialized by Matsushita between 1970 and 1980 as indicated by the following patents: Watanabe et al: “Primary Cell for Electric Batteries”, U.S. Patent 3,536,532 (1970); Watanabe et al: “High Energy Density Battery”, U.S. Patent 3,700,502 (1972); Fukuda et al: “Active Material for Positive Electrode of Battery”, U.S. Patent 4,271,242 (1981).

[0011] The Li-CFXbattery has a very high theoretical specific energy of 2180 Wh / kg at a capacity of 864 mAh / g (at a carbon to fluorine molar ratio of x=l) and an open circuit voltage (OCV) of 3.2-3.3 V. Li-CFXbatteries have a long shelf-life as they lose only 0.5% capacity per year. As of 2024, Li-CFXbatteries are not rechargeable. Their drawbacks include large amountof heat generation during discharge and relatively small power density (up to about 0.9 kW / kg at about 1750 Wh / kg) in their traditional implementation (R. Yazami et al: “Fluorinated carbon nanofibres for high energy and high power densities primary lithium batteries”, Electrochemistry Communications, vol. 9, no. 7, pp. 1850-1855, 2007). The admixture of significant amount of MnO2to CFXbecame a standard method to improve the power density of Li-CFXcells in the hybrid Li-CFx / MnO2ones at the expense of significantly decreased energy densities (6.6 kW / kg at 750 Wh / kg) as discussed in Li et al: "The tunable electrochemical performances of carbon fluorides / manganese dioxide hybrid cathodes by their arrangements", Journal of Power Sources 274 (2015): 1292-1299. Such hybrid Li-CFx / MnO2cells were optimized for use in state-of-the art electric drones (Ndzebet et al: “High Power and High Rate Li / CFx-MnO2Pouch Cell Hybrid Technology”, in Proceedings of the 48th Power Sources Conference, Denver, CO, USA (2018); pp. 558-561.).

[0012] Recently, a number of improvements on the Li-CFXbattery enabled extraordinarily large power density (in the order of 10-100 kW / kg) while maintaining at least -1000 Wh / kg energy density per weight of CFx. Examples of these advancements were published in C. Peng et al: “Fluorinated graphene nanoribbons from unzipped single-walled carbon nanotubes for ultrahigh energy density lithium-fluorinated carbon batteries”, Science China Materials, vol. 64, no. 6, pp. 1367-1377 (2021); Luo et al: “Ultrafast Li / fluorinated graphene primary batteries with high energy density and power density”, ACS Applied Materials & Interfaces, vol. 13, no. 16, pp. 18809-18820 (2021); Dai et al: “Surface modified CFXcathode material for ultrafast discharge and high energy density”, J. Mater. Chem. A, vol. 2, no. 48, pp. 20896-20901 (2014); Jiang et al: “The electrochemical performance of fluorinated ketjenblack as a cathode for lithium / fluorinated carbon batteries”, RSC Advances, vol. 11, no. 41, pp. 25461-25470 (2021); Wang et al: “The fluorination of boron-doped graphene for CFXcathode with ultrahigh energy density”, Energy & Environment Materials 6, no. 4, el2437 (2023); and Li et al: “Gaseous electrolyte additive BF3for high-power Li / CFx primary batteries,” Energy Storage Materials, vol. 38, pp. 482-488 (2021). The key to the success of these approaches is that they avoid the crystallization of the discharge product LiF in the pores of the cathode as opposed to traditional Li-CFXbatteries. Therefore, the pores remain open and allow for fast transport of Li+ions even at high power densities.

[0013] Unfortunately, most of these advanced Li-CFXbatteries require extensive modifications in the current manufacturing processes of Li-CFXbatteries and significantly increase production costs. In 2011, Jones and Hossain proposed a simple solution to reduce the heat development in Li-CFXbatteries during discharge (Jones, S.C. and Hossain, S.: “Polymer Materials as Binder for a CFXCathode”, U.S. Patent Application 13 / 010,431 (2011). This solution was based on the exchange of the traditional teflon (PTFE) or poly vinylidene difluoride (PVDF) binder to other binders which can form complexes with either Li+or F ions and therefore slow down the process of crystallization of the discharge product LiF. One of their proposed binders is polyacrylonitrile (PAN). This solution was proposed to be especially helpful in the case of fast discharge and is relatively easy to be adopted in existing manufacturing facilities.Unfortunately, this patent application did not contain experimental proof of the concept and was abandoned. The proposal was ignored in the scientific and engineering community till a recentwork proved simultaneous high-energy and high-power Li-CFXusing a PAN binder (Huo, H.; Radhakrishnan, S.; Shaw, L.L.; Nemeth, K. “High-Energy and High-Power Primary Li-CFXBatteries Enabled by the Combined Effects of the Binder and the Electrolyte”, Batteries 2023, 9, 268). The latter work, however, also found that the use of a suitable binder alone is not sufficient to achieve high-power. It also requires a suitable electrolyte, such as LiBF4or LiC104. Other electrolytes, such as LiPF6or Li-bis(oxalato)borate (LiBOB) proved inefficient in achieving high power density. The choice of the electrolyte solvent also matters. In practice, a 1 M solution of the previously mentioned salts in a 1 : 1 : 1 volumetric mixture of propylene carbonate (PC), 1,2-dimethoxy ethane (DME) and 1,3 -di oxalane (DOL) solvents proved most effective.

[0014] The intercalation of small and medium size polymers, salts and electrolytes in 2D layered materials was studied in graphene oxide (GO), MoS2, MnO2, and other 2D materials for the purpose of accelerated ion transport and greater power density in batteries. It was demonstrated in graphene oxide cathodes that very high power density can be achieved when the interlayer distance is at least as large as to be able to accommodate a Li ion with its solvation shell (i.e. larger than 10 A). This is discussed in the following works: Kornilov et al: "Li / graphene oxide primary battery system and mechanism", Battery Energy 1, no. 2 (2022): 20210002; Kim et al: “All-graphene-battery: Bridging the gap between supercapacitors and lithium ion batteries”, Sci Rep, vol. 4 (2014); Liu et al: “Lithium super-battery with a chemically functionalized disordered carbon cathode,” US20120077080A1 (2014); Jang et al: “Graphene surface-enabled lithium ion-exchanging cells: Next-generation high power energy storage devices,” Nano Lett, vol. 11, no. 9, pp. 3785-3791 (2011); and Kim et al: “Novel transition-metal-free cathode for high energy and power sodium rechargeable batteries” Nano Energy, vol. 4, pp. 97-104 (2014).

[0015] Diamines are one example of small and medium size organic molecule intercalation in CFx as described in Li et al: "Chemical reactivity of C-F bonds attached to graphene with diamines depending on their nature and location." Physical Chemistry Chemical Physics 18, no. 26 (2016): 17495-17505. In this study, ethylenediamine (EDA), hexamethylenediamine (HDA) and poly(oxypropylene)diamine (PEA) were used to intercalate and covalently functionalize CFX. X-ray diffraction clearly indicated the substantially increased interlayer distance. For example, the intercalation of the relatively small EDA molecule in CFXchanges the angle of the (001) reflection of CFXfrom 11.3 degrees to 9.46 degrees (16% reduction) as indicated by the maxima of the corresponding broad (001) reflections. In the present disclosure, the term organic molecule is a reference to molecules which contain carbon and at least another different element and at least one of C-H and C-C covalent bonds.

[0016] Acrylonitrile monomers are another example of small organic molecule intercalation and covalent functionalization of CFx as discussed in Jiang et al: "Amidoxime-grafted Fluorinated graphene nanosheets as a trace electrochemical sensing platform of uranyl ion." Microchemical Journal (2024): 111371. Acrylonitrile was polymerized in the presence of CFXand was grafted to CFX(formed covalent bonds with CFX) at the same time.

[0017] The intercalation of polymers in 2D materials has been demonstrated for example in Feng et al: "A polymer-direct-intercalation strategy for MoS2 / carbon-derived heteroaerogels with ultrahigh pseudocapacitance." Nature communications 10, no. 1 (2019): 1372.

[0018] The intercalation of polymers in coke or coal using supercritical fluids and solutions of polymers in supercritical fluids was proposed in A. Zhamu and B. Z. Jang: “Supercritical fluid production of graphene-based supercapacitor electrode from coke or coal”, US Patent 11121360B2 (2021), for the purpose of supercapacitor electrodes.

[0019] Glycol as dissolved in supercritical carbon dioxide (scCO2) was used as a molecular wedge to increase the efficiency of intercalation of CO2in CFXin Chen et al: "Fabrication of fluorographene nanosheets with high yield and good quality based on supercritical fluid-phase exfoliation." Journal of Nanoparticle Research 18 (2016): 1-12.

[0020] The role of interlayer expansion by intercalating “pilaring salts” in 2D layered materials as a means to increase ionic conductivity was described in Yao et al: "Method of activating two-dimensional materials for multivalent / polyatomic-ion intercalation battery electrodes." U.S. Patent Application 15 / 735,423 (2018) and U.S. Patent 11,749,795 (2023). This patent, however, limited the type of the intercalating agent to salts. Interlayer expansion optimized for the intercalation of magnesium ions was described in Doe et al: “Layered materials with improved magnesium intercalation for rechargeable magnesium ion cells”. U.S. Patent 9,401,528 (2016).SUMMARY OF THE INVENTION

[0021] The present invention is centered around the intercalation of polymers, oligomers and small organic molecules in 2D layered carbon fluorides (CFX), such as graphite fluoride, fluorinated carbon fiber, coal or coke and the utilization of the intercalation complex as cathode active material in electrochemical energy storage devices. The intercalated CFXis advantageous for achieving simultaneous high-energy and high-power in metal-CFxbatteries, the metal being Li, Na, K, Mg, Ca, Zn and any metallic element. The high power density is due to the expansion of the interlayer distance and several other beneficial effects of the intercalating molecules, such as for example the inhibition of the growth of crystallites of the discharge product.

[0022] As opposed to the dual role of the polymer in the previously mentioned approaches (mechanical binder connecting CFXparticles in the cathode and inhibitor of discharge product crystallization), in the present invention, the polymer also plays a third role, namely that of the interlayer expansion agent. Thus, the binder is not only present between the CFXparticles but also inside them. This way, the performance of the metal-CFx battery can be optimized further. In some implementations, an oligomer or a small organic molecule plays the role of the intercalation agent in which case the binder polymer plays only the above mentioned dual role. The intercalated polymers, oligomers and small organic molecules preferentially form covalent bonds with CFX, this accelerates the intercalation and also prevents the formation of isolated phases of the CFXand the polymer.

[0023] Furthermore, if the partial functionalization of the surface of the carbon layer by the intercalation agent is stable during discharge, it will result in a non-planar carbon layer after the discharge. The re-fluorination of the non-coplanar carbon layer will require less activation energy than that of a planar one as the non-planar layer is already in an activated state. As there is less geometric change in the carbon layer during discharge, the heat produced during discharge is also reduced.DETAILED DESCRIPTION OF THE INVENTION

[0024] Figure 1 indicates the structure of CFXintercalated by polymers (or other molecules). There is sufficient space between the layers and the polymers to further intercalate cations with solvation shells and solvent molecules in the intercalation complex of Fig 1.

[0025] Preferred polymers contain elements, such as side-chains, which are capable for a nucleophilic attack on the carbon atoms of CFXwhereby they form a covalent bond between the polymer and CFXand substitute a fluorine on the surface of a CFXlayer by an atom of the polymer. Furthermore, the preferred polymers contain elements which are capable to form complexes with cations or fluoride anion. Figure 2 shows the covalent functionalization of a monolayer of CFXby a strand of polyacrylonitrile (PAN).

[0026] The intercalated CFXparticles are embedded in the cathode within the battery cell as indicated in Figure 3. During discharge, reactive metal atoms (such as Li) of the anode release metal cations and electrons. The electrons migrate into the cathode via the load outside the battery and induce the formation of fluoride anions and carbon from CFX. The cations also migrate into the cathode but through the ionic conductor inside the battery. The cations and anions recombine to a discharge product salt (such as LiF) in the cathode. The speed of transport of the cations is accelerated by the fact that the intercalated molecules (such as polymers) already expanded the interlayer space in CFXand cations can fit easier between the CFXlayers even when they are solvated. Suitable intercalation agents and binders (such as certain polymers) may inhibit the formation of large crystallites of the discharge product salts in the pores of the cathode and thus maintain a fast discharge for the full capacity of the battery.

[0027] In one preferred embodiment, monolayers of CFXare separated by individual molecules of polyacrylonitrile (PAN) and the preferred overall amount of PAN is 5-10% of the mass of CFXwhile the PAN is uniformly distributed in each interlayer space. The intercalation of this kind is indicated by a significant shift of the (001) reflection toward lower angles in the x-ray diffraction pattern of the CFXas compared to pristine CFX.

[0028] In another embodiment, the polymer is one of polyacrylic acid, polyacrylate, polyacrylamide and salts of polyacrylic acid. Polyacrilic acid and its salts and esters have the ability to covalently bind to CFXvia nucleophilic substitution.

[0029] In a third embodiment, the polymer is one of polyvinyl alcohol and polyvinyl amine.

[0030] In a forth embodiment, the polymer is polyethylenimine (PEI) in one of a linear and a branched form.

[0031] In a fifth embodiment, the polymer is a co-polymer of tetrafluoroethylene, for example with acrylonitrile. The chemical formula of the latter co-polymer is (C2F4)n(CH2CHCN)mwhere n and m are positive integer numbers. Alternatively, any derivative of poly(tetrafluoroethylene) with functional groups substituting one of more fluorine atoms may also be used as the intercalating polymer if the said functional group is capable to covalently bind to CFX.

[0032] In a sixth embodiment, the intercalating molecule is an amino (-NH2) or cyano (-CN) terminated oligomer of tetrafluoro-ethylene with the chemical formula of NH2(C2F4)nNH2and NC(C2F4)nCN, respectively. In this case, the extra fluorine content increases the capacity of the cathode.

[0033] In a seventh embodiment, the intercalating agents include small organic molecules that are capable to covalently bind to CFXvia nucleophilic substitution. Here, the size reference “small” refers to smaller molecular mass than 1500 daltons. Examples of such small molecules include organic molecules with one or more amine (-NRiR2), hydroxyl (-OH), carboxyl (- COOH), carboxylate (-COO ), amid (-CONRIR2), nitrile (-CN), ester (-COORi) functional groups, where Ri and R2denote additional organic functional groups, such as alkyl groups. One particular example of this group is oxalyl compounds with the general formula of Y-C(=O)- C(=O)-Z where Y and Z are one of a halide atom, an alkoxy group, a cyano group, an amino group and a functionalized amino group. Examples of such oxalyl compounds include oxalyl chloride, oxalyl fluoride, esters of oxalic acid and oxamide.

[0034] In a yet another embodiment, the intercalating agents are monomers of the above mentioned intercalating polymers and these monomers may polymerize in situ during intercalation or by activation after the intercalation.

[0035] The preferred method for intercalating the polymer in CFXis based on making a slurry of CFXin a solvent which can dissolve the given polymer and then exposing the slurry to shear, for example in a planetary ball mill or in a high shear mixer. For example, dimethyl formamide is a good solvent of polyacrylonitrile. The process may further be accelerated by exposing the slurry to a supercritical fluid, such as supercritical CO2(sCO2). In some cases, the polymer may dissolve in the supercritical fluid and in this case no organic solvent is required. In yet another case, the monomer of the polymer dissolves well in the supercritical fluid (for example acrylonitrile in scCO2) and can be polymerized in situ during intercalation in CFX.

[0036] In yet another embodiment, polymers spontaneously intercalate into CFX. For example, branched polyethylenimine (PEI) is a liquid at room temperature and can spontaneously intercalate in some CFXwhen in contact. The intercalation of PEI, PAN and other polymers in CFXis supported by the formation of covalent bonds between CFXand the polymer as the polymer is capable of carrying out a nucleophilic substitution in CFX.

[0037] It is desirable that the cathode can be as thick as possible to reduce the amount (mass) of the cathode current collector and thus maximize the specific energy of the cell. A thick cathode however requires a very fast ion conduction in its whole volume for high power operation. In order to achieve this goal, the ionic conductivity of the individual intercalated CFXparticles has to be optimized. The larger the amount of intercalated molecules the larger the interlayer openspace for the transport of solvated cations and the faster the cation transport. However, as the amount of intercalated molecules increases, the specific energy of the intercalated individual particles decreases. In consideration of these factors, the optimum amount of intercalated polymers and other molecules is typically 5-10 % of the mass of the pristine CFXparticles and the fact of the intercalation is indicated by an at least 5 % reduction in the angle of the peak of the corresponding broad (001) reflection of CFXwhen using 1.5406 A wavelength (Cu K-a) x- rays. Typically, the peak of the broad (001) reflection of pristine CFX(with x=l) is at 13-14 degrees.

[0038] It is to be understood that the above-described arrangements are only illustrative of the application of the principles of the present invention. Numerous modifications and alternative arrangements may be devised by those skilled in the art without departing from the spirit and scope of the present invention and the appended claims are intended to cover such modifications and arrangements. It is intended that the scope of the invention not be limited by the specification, but be defined by the claims set forth below.

[0039] All publications and patent documents cited in this application and the related provisional application are incorporated by reference in their entirety for all purposes to the same extent as if each individual publication or patent document were so individually denoted.

Claims

CLAIMS:

1. An electrochemical energy storage device wherein the positive electrode electroactive material in its charged state is a layered carbon fluoride (CFX) having an at least 5 % fluorine content per mass and the CFXis intercalated by one of a polymer, an oligomer and a small organic molecule whereby the intercalating molecules form covalent bonds with the CFXand the intercalated CFXhas an at least 5 % smaller scattering angle than the pristine CFXat the maximum intensity of the (001) reflection when using 1.5406 A wavelength (Cu K-a) x-rays.2 The electrochemical energy storage device of Claim 1 in which the polymer is polyacrylonitrile.3 The electrochemical energy storage device of Claim 1 in which the polymer is one of polyacrylic acid and salts and esters of polyacrylic acid.4 The electrochemical energy storage device of Claim 1 in which the polymer is polyethylenimine.5 The electrochemical energy storage device of Claim 1 in which the polymer is one of polyvinyl alcohol and polyvinyl amine.6 The electrochemical energy storage device of Claim 1 in which the polymer is a co-polymer of oxalic acid.7 The electrochemical energy storage device of Claim 1 in which the intercalating small molecule contains the oxalyl functional group and has the general formula of Y-C(=O)-C(=O)-Z where Y and Z are one of a halide, an alkoxy group, a cyano group, an amino group and a functionalized amino group.8 The electrochemical energy storage device of Claim 1 in which the polymer is a polyester.9 The electrochemical energy storage device of Claim 1 in which the polymer is a polyamide.10 The electrochemical energy storage device of Claim 1 in which the intercalating molecule is one of a co-polymer and an oligomer of tetrafluoroethylene containing functional groups which can covalently bind to CFx.11 The electrochemical energy storage device of Claim 1 in which the intercalating molecule is one of ethylene glycole, its oligomers and polyethylene glycol.12 The electrochemical energy storage device of Claim 1 in which the small molecule contains one or more amine (-NR1R2), hydroxyl (-OH), carboxyl (-COOH), carboxylate (-COO ), amid (-CON 1R2), nitrile (-CN), ester (-COORi) functional groups, where Ri and R2denote organic functional groups, such as alkyl groups or hydrogen.13 The electrochemical energy storage device of Claim 1 in which the small molecule is a diamine where the amino groups terminate both ends of an oligomeric chain.14 The electrochemical energy storage device of Claim 1 in which the small molecule is one of ethylenediamine and hexamethylenediamine and poly(oxypropylene)diamine having a molecular weight of up to 2000 dalton.

15. A method for the intercalation of layered CFXmaterials by polymers, oligomers and small molecules in a sluriy formed in one of a liquid and a supercritical fluid medium by mixing the components and exposing them to shear.

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