Mechanochemical process for the synthesis of alkali metal-carbon alloys

Abstract

Provided herein are methods for preparing alkali metal-carbon alloys from metals and sources of elemental carbon comprising applying mechanical force to a precursor mixture.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority to U.S. Provisional Application No. 63 / 742,925, filed Jan. 8, 2025, the entire contents of which are incorporated by reference herein.BACKGROUND

[0002] Carbon alloys of some transition metals (Periodic Table Groups 3-12) have been known for some time. These alloys provide access to metallic materials with properties modified from those observed for the pure “host” metal. These modified properties are generally useful in material science and industry, often providing harder, more chemically resistant, and higher melting metallic materials. Although such metal-carbon alloys are relatively common with the transition metals, they remain extremely rare with alkali metals (group I elements). Recently, alkali metal / carbon compositions have become of interest in superconductor and advanced battery technology. However, synthetic access to such compositions remains extremely limited. A low temperature, cost-effective preparation with the capability of wider product diversity would facilitate the use of alkali metal compositions more broadly and simplify subsequent fabrication into advanced devices. Accordingly, there exists a need for convenient, low-temperature methods of preparing alkali metal-carbon alloys.SUMMARY OF THE INVENTION

[0003] In certain aspects, provided herein are alloys comprising carbon and a group 1 metal.

[0004] In further aspects, provided herein are methods of making an alkali metal-carbon alloy comprising:

[0005] contacting a group 1 metal with a source of elemental carbon to form a precursor mixture; and

[0006] applying a mechanical force to the precursor mixture;

[0007] thereby producing the alkali metal-carbon alloy.DETAILED DESCRIPTION OF THE INVENTION

[0008] The present disclosure includes exemplary process conditions (e.g., temperature, ball mill rotational frequencies, rates, etc.) that provide certain advantages in context of the systems and methods disclosed herein. However, any suitable conditions may be used, and the person of ordinary skill in the art will appreciate how to vary the conditions of any particular process described herein to obtain results and tune product distribution as needed for particular applications, as contemplated.ALKALI METAL-CARBON ALLOY COMPOSITIONS

[0009] In certain aspects, provided herein are alloys comprising carbon and a group 1 metal.

[0010] In certain embodiments, the carbon and the group 1 metal are each neutrally charged. In some embodiments, the alloy does not comprise any carbon having a formal charge other than zero. In certain embodiments, the alloy does not comprise any non-group 1 metals.

[0011] In certain aspects, provided herein are alloys consisting of carbon and a group 1 metal.

[0012] In certain embodiments, the group 1 metal is selected from sodium, potassium, rubidium, and caesium. In further embodiments, the group 1 metal is sodium. In yet further embodiments, the group 1 metal is potassium. In still further embodiments, the group 1 metal is rubidium. In certain embodiments, the group 1 metal is caesium.

[0013] In certain embodiments, the melting point of the alloy is greater than about 100° C. In further embodiments, the melting point of the alloy is greater than 180° C. In yet further embodiments, the melting point of the alloy is about 200° C. In still further embodiments, the melting point of the alloy is greater than 400° C.

[0014] In certain embodiments, the group 1 metal has a neutral formal charge. In some embodiments, wherein the group 1 metal is not formally cationic.

[0015] In certain embodiments, wherein the carbon has a neutral formal charge. In some embodiments, wherein the carbon has a formal charge of zero.

[0016] In certain embodiments, the alloy is a solid at about 25° C. and about 1 atm.

[0017] In certain embodiments, the alloy is a solid solution, wherein the carbon is the solute and the group 1 metal is the solvent. In some embodiments, the carbon is dissolved in the group 1 metal.

[0018] In certain embodiments, the alloy comprises less than about 70 wt % carbon. In further embodiments, the alloy comprises from about 1 wt % to about 50 wt % carbon. In yet further embodiments, the alloy comprises from about 1 wt % to about 40 wt % carbon. In still further embodiments, the alloy comprises from about 1 wt % to about 30 wt % carbon. In certain embodiments, the alloy comprises from about 1 wt % to about 20 wt % carbon. In further embodiments, the alloy comprises about 1 wt % carbon. In yet further embodiments, the alloy comprises about 5 wt % carbon. In still further embodiments, the alloy comprises about 10 wt % carbon. In certain embodiments, the alloy comprises about 15 wt % carbon. In further embodiments, the alloy comprises about 20 wt % carbon. In yet further embodiments, the alloy comprises about 25 wt % carbon. In still further embodiments, the alloy comprises about 30 wt % carbon. In certain embodiments, the alloy comprises about 35 wt % carbon. In further embodiments, the alloy comprises about 40 wt % carbon. In yet further embodiments, the alloy comprises about 45 wt % carbon. In still further embodiments, the alloy comprises about 50 wt % carbon.

[0019] In certain embodiments, the alloy is conductive to electric current. In certain embodiments, the alloy is lustrous. In certain embodiments, the alloy is malleable. In further embodiments, the alloy is less malleable than the group 1 metal in elemental form.

[0020] In certain embodiments, the alloy has a melting point greater than the melting point of the group 1 metal in elemental form.

[0021] In certain embodiments, the group 1 metal is not intercalated between layers comprising the carbon.

[0022] In certain embodiments, the group 1 metal is not intercalated between graphene or graphite layers.

[0023] In certain embodiments, when the alloy is contacted with a source of H+, dihydrogen, alkali metal cations, and a neutrally charged carbon allotrope are produced.

[0024] In certain embodiments, when the alloy is contacted with a source of H+, hydrocarbons are not produced.

[0025] In certain embodiments, provided herein are alloys consisting of carbon and a group 1 metal, prepared according to a method of the present disclosure.Methods of Making Alkali Metal-carbon Alloys

[0026] In certain aspects, provided herein are methods of making an alkali metal-carbon alloy comprising:

[0027] contacting a group 1 metal with a source of elemental carbon to form a precursor mixture; and

[0028] applying a mechanical force to the precursor mixture;

[0029] thereby producing the alkali metal-carbon alloy.

[0030] In certain embodiments, contacting the group 1 metal with the source of elemental carbon is conducted in the absence of a liquid (e.g., a solvent). In some embodiments, the method does not comprise suspending the group 1 metal and the source of elemental carbon in a liquid (e.g., a solvent).

[0031] In certain embodiments, applying the mechanical force comprises milling the group 1 metal and source of elemental carbon. In further embodiments, applying the mechanical force comprises ball-milling the group 1 metal and source of elemental carbon. In yet further embodiments, applying the mechanical force is carried out in a planetary ball mill reactor. In still further embodiments, applying the mechanical force is carried out in a reactor comprising an auger. In certain embodiments, applying the mechanical force is carried out in a reactor comprising a gyroscopic vortex mixer.

[0032] In certain embodiments, applying the mechanical force is carried out in a reactor comprising a screw extruder.

[0033] In certain embodiments, the group 1 metal is sodium. In further embodiments, the group 1 metal is potassium. In yet further embodiments, the group 1 metal is rubidium. In still further embodiments, the group 1 metal is caesium.

[0034] In certain embodiments, the source of elemental carbon is selected from biochar, charcoal, graphite, carbon black, coal, diamond, a fullerene, coke, or a combination thereof. In further embodiments, the source of elemental carbon is charcoal. In yet further embodiments, the source of elemental carbon is coconut fiber charcoal. In still further embodiments, the source of elemental carbon is biochar. In further embodiments, the source of elemental carbon is suitably prepared biochar.

[0035] In certain embodiments, the mechanical force is applied to the precursor mixture under an inert atmosphere. In further embodiments, the mechanical force is applied to the precursor mixture under an atmosphere that is essentially free of water, oxygen, carbon dioxide, and other known reactive gases. In yet further embodiments, the mechanical force is applied to the precursor mixture under an atmosphere that is essentially free of nitrogen. In still further embodiments, the mechanical force is applied to the precursor mixture under an atmosphere of argon.

[0036] In certain embodiments, the method is carried out under an inert atmosphere. In further embodiments, the method is carried out under an atmosphere that is essentially free of water and oxygen. In yet further embodiments, the method is carried out under an atmosphere that is essentially free of nitrogen. In still further embodiments, the method is carried out under an atmosphere of argon.

[0037] In certain embodiments, the mechanical force is applied to the precursor mixture for at least about 1 hour. In further embodiments, the mechanical force is applied to the precursor mixture from about 1 hour to about 2 weeks.

[0038] In certain embodiments, the mechanical force is applied to the precursor mixture at a temperature from about −78° C. to about 60° C. In certain embodiments, the mechanical force is applied to the precursor mixture at a temperature from about −10° C. to about 200° C. In some embodiments, the mechanical force is applied to the precursor mixture at a temperature from about −10° C. to about 120° C. In further embodiments, the mechanical force is applied to the precursor mixture at a temperature from about 20° C. to about 120° C. In yet further embodiments, the mechanical force is applied to the precursor mixture at a temperature from about 20° C. to about 80° C. In still further embodiments the mechanical force is applied to the precursor mixture at a temperature from about 20° C. to about 60° C. In certain embodiments the mechanical force is applied to the precursor mixture at a temperature from about 20° C. to about 40° C. In certain embodiments, the mechanical force is applied to the precursor mixture at a temperature of about 20° C. In some embodiments, the mechanical force is applied to the precursor mixture at a temperature of about 25° C. In further embodiments, the mechanical force is applied to the precursor mixture at a temperature of about 30° C. In yet further embodiments, the mechanical force is applied to the precursor mixture at a temperature of about 40° C. In still further embodiments, the mechanical force is applied to the precursor mixture at a temperature of about 50° C. In certain embodiments, the mechanical force is applied to the precursor mixture at a temperature of about 60° C. In further embodiments, the mechanical force is applied to the precursor mixture at a temperature of about 70° C. In yet further embodiments, the mechanical force is applied to the precursor mixture at a temperature of about 80° C.

[0039] In certain embodiments the mechanical force is applied to the precursor mixture at about ambient temperature.

[0040] In some embodiments, the mechanical force is applied to the precursor mixture without external heating.

[0041] In certain embodiments, the only heat applied to the reaction is heat generated by the method (e.g., frictional heat generated by applying the mechanical force to the precursor mixture).

[0042] In certain embodiments, the mechanical force is applied to the precursor mixture by rotating a ball mill canister at from about 400 Revolutions Per Minute (rpm) to about 700 rpm. In some embodiments, the mechanical force is applied to the precursor mixture by rotating a ball mill canister at from about 200 rpm to about 800 rpm. In further embodiments, the mechanical force is applied to the precursor mixture by rotating a ball mill canister at from about 300 rpm to about 800 rpm. In yet further embodiments, the mechanical force is applied to the precursor mixture by rotating a ball mill canister at from about 300 rpm to about 600 rpm. In certain embodiments, the mechanical force is applied to the precursor mixture by rotating a ball mill canister at about 600 rpm.

[0043] In certain embodiments, the mechanical force is applied to the precursor mixture by rotating a ball mill canister at a variable rate from about 200 rpm to about 800 rpm.

[0044] In some embodiments, the rate of rotation of the ball mill canister is changed at least two times, and the direction of rotation (e.g., clockwise or counterclockwise) is changed with every other change to the rate of rotation. In further embodiments, the mechanical force is applied to the precursor mixture by rotating a ball mill canister at about 300 rpm for 23 minutes, pausing rotations for 15 seconds, then rotating at about 600 rpm for 47 minutes, pausing the rotations for another 15 seconds and repeating this sequence of rotations in the reverse direction, and then resuming the original rotation direction, continuing to switch the speed and direction of rotation over the course of the entire milling process.

[0045] In certain embodiments, the mechanical force is applied to the precursor mixture by rotating a ball mill canister at about 300 rpm for 23 minutes, pausing rotations for 15 seconds, then rotating at about 600 rpm for 47 minutes, pausing the rotations for another 15 seconds and repeating this sequence of rotations in the reverse direction, and then resuming the original rotation direction, continuing to switch the speed and direction of rotation over the course of an entire milling process lasting about 1 day.

[0046] In some embodiments, the mechanical force is applied to the precursor mixture by rotating a ball mill canister at about 300 rpm for 23 minutes, pausing rotations for 15 seconds, then rotating at about 600 rpm for 47 minutes, pausing the rotations for another 15 seconds and repeating this sequence of rotations in the reverse direction, and then resuming the original rotation direction, continuing to switch the speed and direction of rotation over the course of an entire milling process lasting about 2 days.

[0047] In certain embodiments, the mechanical force is applied to the precursor mixture by rotating a ball mill canister at about 300 rpm for 23 minutes, pausing rotations for 15 seconds, then rotating at about 600 rpm for 47 minutes, pausing the rotations for another 15 seconds and repeating this sequence of rotations in the reverse direction, and then resuming the original rotation direction, continuing to switch the speed and direction of rotation over the course of an entire milling process lasting about 1 week.

[0048] In some embodiments, the mechanical force is applied to the precursor mixture by rotating a ball mill canister at about 300 rpm for 23 minutes, pausing rotations for 15 seconds, then rotating at about 600 rpm for 47 minutes, pausing the rotations for another 15 seconds and repeating this sequence of rotations in the reverse direction, and then resuming the original rotation direction, continuing to switch the speed and direction of rotation over the course of an entire milling process lasting about 2 weeks.

[0049] In certain aspects provided herein is a metal carbide prepared according to a method of the present disclosure.Definitions

[0050] Unless otherwise defined herein, scientific and technical terms used in this application shall have the meanings that are commonly understood by those of ordinary skill in the art. Generally, nomenclature used in connection with, and techniques of, chemistry described herein, are those well-known and commonly used in the art.

[0051] The methods and techniques of the present disclosure are generally performed, unless otherwise indicated, according to conventional methods well known in the art and as described in various general and more specific references that are cited and discussed throughout this specification.

[0052] Chemistry terms used herein, unless otherwise defined herein, are used according to conventional usage in the art, as exemplified by “The McGraw-Hill Dictionary of Chemical Terms”, Parker S., Ed., McGraw-Hill, San Francisco, C.A. (1985).

[0053] As used herein, the term “inert atmosphere” refers to an atmosphere that does not comprise a significant amount of one or more species (e.g., water, oxygen, nitrogen, and / or carbon dioxide) known to react with a compound of interest (e.g., the metal carbide) or a starting material (e.g., group 1 or 2 metal) from which a compound of interest is derived. Non-limiting examples of common inert atmospheres relevant to the present disclosure include gaseous mixtures that comprise essentially no water, no dioxygen, no dinitrogen, and gaseous mixtures consisting essentially of argon, or other noble gases, or under vacuum.

[0054] As used herein the term “suitably prepared” used in connection with charcoal and biochar refers to charcoal and / or biochar material that has undergone a heating process under vacuum that removes essentially all water, residual wood extractives, and any other contaminants that could interfere with the process of this invention. A preferred example of biochar preparation is provided herein, however any suitable process may be used for preparing water-and contaminant-free charcoal and / or biochar for use in the methods of the present disclosure.

[0055] As used herein, the term “source,” e.g., a source of elemental carbon, refers to a composition which either comprises the species to which it refers, or from which the species may be easily obtained by common means known to those of skill in the art. For example, sources of elemental carbon relevant to the present disclosure include, as non-limiting examples, substances comprising elemental carbon (e.g., biochar, charcoal, graphite, carbon black, coal).

[0056] As used herein, the term “alloy,” as in “alkali metal-carbon alloy,” refers to a composition comprising both metal and a carbon moiety (e.g., a carbon atom or multiple carbon atom fragment) where both the metal and carbon moiety have a formally neutral charge, e.g., K0[C]0. As used herein, the term “alloy” does not include compositions have a net-zero formal charge in which the individual components are charged ions (e.g., a metal carbide, such as 2[Li+][C2−2]).

[0057] The term “carbide,” as used herein, refers to a composition comprising a carbon-based anion [e.g., wherein a formal anionic charge is localized primarily on a carbon atom, or a fragment comprising multiple carbon atoms] imparting a formal negative charge on the carbon-containing unit. For example, carbide may refer to a composition comprising a carbontetraide, C4−; an acetylide, C22; an ethentetraide, C24; an allyltetraide, C34−, or other carbon-based anion. Though the terms “metal carbide” and “metal alloy” are frequently used interchangeably in the literature, for this purposes of this disclosure, a distinction is made between an “alloy,” and a “carbide,” as defined above. An alkali metal carbide reacts with proton sources such as water to liberate a hydrocarbon as the primary carbon-containing reaction product, produced by protonation of the formally anion carbon fragment. By contrast, an alkali metal-carbon alloy of the present disclosure reacts with a proton source to produce dihydrogen gas (via reduction of H+ by the alkali metal, producing an alkali metal cation and H2), and the primary carbon-containing reaction product is a charge-neutral carbon allotrope (e.g., carbon black). Hence, as used herein, the terms “alloy” and “carbide” refer to chemically distinct compositions having distinct reactive patterns. The reaction patterns of an alkali metal carbide and an alkali metal-carbon alloy may be used to differentiate between the two composition types. As will be appreciated by one of ordinary skill in the art, the metal to carbon ratio of alkali metal-carbon alloys of the present disclosure may vary and still be considered an alloy as defined above.

[0058] All of the above, and any other publications, patents and published patent applications referred to in this application are specifically incorporated by reference herein. In case of conflict, the present specification, including its specific definitions, will control.EXAMPLES

[0059] The invention now being generally described, it will be more readily understood by reference to the following examples which are included merely for purposes of illustration of certain aspects and embodiments of the present invention, and are not intended to limit the invention.

[0060] When conducted in a typical planetary ball mill such as the PQ-N04 series (Across International), a 500 mL grade 304 stainless steel vessel containing just enough ¾ inch diameter tungsten carbide steel balls weighing about 60 grams each to cover the bottom of the reaction vessel in a mono-layer (typically about 12 balls for a 3.5 inch inner diameter reaction vessel) was employed for the process, but other vessel sizes and ball types may also be employed. One of ordinary skill in the art will be able to select appropriate impact balls for use based on, e.g., vessel size and reaction scales (total mass of reactants). For example, stainless steel vessels, or tungsten carbide steel vessels may be used with stainless steel or tungsten carbide steel balls weighing from about 20 to about 65 grams. In the examples below, unless otherwise specified, the ball weights were about 60 grams.Example 1: Biochar PreparationA 1 L 24 / 40 round bottom flask equipped with a vacuum takeoff adapter was charged with 221.7 g of sawmill char (originating primarily from Southern pine). The char was suitably prepared for the carbide synthesis process by drying under vacuum (less than about 1 mmHg) while heating at about 100° C. until the sample reached a constant mass (about 1 hour). The temperature was then increased as follows: about 150° C. for about 1.5 hours; about 200° C. for about 3.5 hours; about 250° C. for about 1 hour; about 300° C. for about 1 hour; about 350° C. for about 7.5 hours; about 375° C. for about 8.5 hours; and about 400° C. for about 1.5 hours. At this point, the mass of the char was constant. The flask was allowed to cool to room temperature under high vacuum and was then back-filled with argon. The sample lost 139.7 g of water, accounting for 63% of the weight.Example 2: Mechanochemical Synthesis of Sodium-Carbon Alloys

[0062] Procedure: A “500 mL” (~400 mL internal volume) steel ball mill container was filled with with 133.97 g steel balls (8 large (0.62″ diameter)). The ball mill canister was brought into the dry box and was charged with 22.5 g sodium metal (~0.5 cm 3 pieces) (0.977 mol, 2 eq) followed by 23.5 g of high vacuum dried coconut charcoal (1.954 mol, 4 eq). The container was sealed shut except for the central plug, through which argon was allowed to enter the container and purge it. After being purged with argon for 2 minutes the central plug was inserted and screwed tight. The point at which the lid met the base of the canister was taped up with electrical tape as an extra precaution against water / air intrusion. The canister was milled in an Across International PQ-N2 planetary steel ball mill. The canister was set to mill 12 hours forward at 580 RPM followed by 12 hours reverse at 580 RPM repeating for 4 days. Milling was stopped after 2 days and 23 hours and the milling pattern was changed to: 2 hours forward direction at 580 RPM (2 minute pause); 30 minutes forward direction at 300 RPM (2 minute pause); 2 hours reverse direction at 580 RPM (2 minute pause); 30 minutes reverse direction at 300 RPM (2 minute pause). This cycle was repeated 8 times. The canister was brought into the dry box (glovebox) and opened. This revealed that only 3 out of 8 balls were free and uncoated. The rest of the balls were covered in a thick coating of the product and were stuck to the top of the canister. The majority of material was located in the top ½ of the canister. The material proved far too hard to pry off by hand and was considerably harder and less malleable than the initial sodium metal. The material was mostly a shiny metallic like substance, but with some small traces of black material remaining visible. A small piece was removed successfully for subsequent hydrolysis. The canister was purged 30 seconds with argon and then sealed up (this time with the central plug covered with poly(tetrafluoroethylene) resin tape) and set to mill again, but this time upside down. It was milled 30 cycles of: 47 min forward direction at 580 RPM (15 second pause); 23 min forward direction at 300 RPM (15 second pause); 47 min reverse direction at 580 RPM (15 second pause); 23 min reverse direction at 300 RPM (15 second pause). In total the canister was milled for 7 days 14 hours and 2 minutes. The canister was brought into a dry box (glovebox) for workup. The material was found to have become very lustrous (like sodium metal, but much harder) with no real traces of black material left. The compound was still exceedingly hard, but 3.852 g was pried off using a flat head screwdriver. After this another 14.63 g of material was removed by careful drilling, producing small turnings. The next day another 9.01 g of material was removed by drilling. In total, 27.49 g of material was mechanically removed accounting for 59.8% of theoretical amount. The material seemed to slowly tarnish to form a thin black coating, but this was exceedingly slow. Samples were stored under argon to preserve them.

[0063] A melting point sample of the above material was made from a thin sliver of the material. The top of the melting point tube was covered in hydrocarbon wax film to protect the sample from air. The melting point tube was taken out of the dry box (glove box) for analysis. The characteristic melting point of sodium about 98° C. was not observed. No visual change was observed before 180° C. Between ~190-210° C. the metal appeared to get slightly shinier, but no indication of melting. The material was heated to 390° C. with no melting observed. At this latter temperature the wax seal on the tube failed, exposing the material to air and causing rapid degradation.

[0064] The remaining material in the canister was hydrolyzed in order to remove it and to analyze the gas. To do this the milling jar (canister) was placed in a one-gallon metal (paint) can with the milling lid sitting alongside the jar and the balls still in the milling jar. The gallon can was sealed with its friction press lid. The gallon with the milling jar and its remaining contents can were removed from the dry box and connected to a bubbler through a hole punched into the lid and flushed with dinitrogen. Once properly purged, a large amount 1-2 L) isopropanol was added using a funnel through a second hole made in the center of the lid. After this it was followed by 0.5-1 L methanol and then eventually water to ensure complete hydrolysis. After the hydrolysis had gone for a while, the central hole was covered with duct tape and a ~50-100 mL gas sample was removed by glass syringe and bubbled through CDCl3. This sample was analyzed by 1H and 13C NMR. Dihydrogen was observed and small traces of ethylene, and acetylene were visible (possibly arising from trace metal contamination in the sodium used for the process.) The bulk hydrolysis produced significant amounts of carbon which were collected in a large Erlenmeyer flask. The solution was neutralized with about 200 mL of approximately 2N HCl. This final pH was around 6. The Erlenmeyer flask was allowed to stand overnight to settle. The following day, the top layer was suctioned off leaving about 700 mL of material in the bottom. It was allowed to sit for around an hour and then the top layer was again suctioned off leaving around 400 mL ready for filtration. The separated liquid was also saved to recover the remaining carbon freed from the sodium solution (alloy) by filtration. In total 8.66 g carbon was isolated.Example 3: Mechanochemical Synthesis of Potassium-Carbon Alloy

[0065] A “500 mL” (~400 mL internal volume) steel ball mill container was filled with 169.6 g steel balls (6 large (¾″ diameter)) along with 360.6 g tungsten carbide balls (6 large (3 / 4″ diameter)). The ball mill canister was brought into a dry box (glovebox) and was charged with 2.618 g high vacuum dried coconut charcoal (0.218 mol, 2 eq) followed by 4.242 g potassium metal (cleaned to remove tarnish and mineral oil) (one solid chunk) (0.108 mol, 1 eq). The container was sealed shut except for the central plug, through which Argon was allowed to enter the container and purge it. After being purged with Argon for 5 minutes the central plug (covered with poly(tetrafluoroethylene) resin tape) was inserted and screwed tight. The point at which the lid met the base of the canister was taped up with electrical tape for good measure. The canister was milled in an Across International PQ-N2 planetary steel ball mill. The canister was set to run 20 cycles of: 47 minutes forward direction at 580 RPM (15 second pause); 23 minutes forward direction at 300 RPM (15 second cooldown); 47 minutes reverse direction at 580 RPM (15 second pause); and 23 minutes forward direction at 300 RPM (15 second pause). During the first cycle, the 23 minute reverse cycle was not selected so it was missed. It was added back and run normally after that point. Initially there was a lot of strong vibrations from the machine, but this died down in the first hour. The temperature was checked by hand measurement after about 15 minutes, and the canister was found to be around room temperature. The milling was stopped 8 min 26 seconds into the 11th cycle and the canister was mechanically impacted to loosen stuck balls and material. The canister was flipped upside down and allowed to continue milling with the same program. No strong vibrations were observed after starting them upside down. This suggests a uniform material distribution. The canister was still room temperature when it was flipped. The canister did not seem to have stuck balls. Canister was run upside down for a little under 1 cycle. It was stopped 7 min and 53 seconds into the 300 RPM reverse cycle of cycle 11. The canister was mechanically impacted as before to loosen and compacted material that hight have accumulated in corners and crevices, flipped back upright, and the milling pattern was changed to: 23 minutes forward direction at 300 RPM (15 second pause); 47 minutes forward direction at 580 RPM (15 second pause); 23 minutes forward direction at 300 RPM (15 second pause); and 47 minutes reverse direction at 580 RPM (15 second pause). It was stopped on the 8th cycle at the start of the fast reverse cycle. In total the canister was milled for 1 day 20 hours and 11 minutes. The canister was brought into the dry box for workup. The material proved to form an alloy material very similar to the Na-C alloy. The K-C alloy is slightly softer than the Na-C alloy, but still much harder than potassium metal itself. It was possible to pry the alloy out of the canister using a stiff spatula. Ultimately, 6.11 g of material was isolated, the rest was hydrolyzed in a somewhat similar process to that described above for the sodium-carbon alloy. A melting point was taken on the K-C alloy. There was no melting observed at the characteristic potassium melting point of about 64° C. No true melting behavior was observed up to 400° C.Hydrolysis of Residual Alloy in the Milling JarThe remaining material in the milling jar was hydrolyzed directly in the jar itself without the use of a secondary container such as that used in the procedure with sodium. The milling jar was closed with its lid in the dry box (glovebox) and a T-shaped adapter was screwed into the central plug hole. The two other tubulation openings in the T-adapter were capped with septa. The canister was brought out of the dry box (glovebox) for the hydrolysis. A three-way stopcock was set up, connected on one side to nitrogen through a bubbler and to a tube for gas collection on one side. The system was purged with nitrogen and then the canister was hooked up to the horizontal connection on the metal T-joint. With only the canister and bubbler connected isopropanol was injected into the canister causing visible gas evolution. After around 100-200 mL of isopropanol had been injected, a mixture of isopropanol and water was injected to complete the hydrolysis. This was swirled around to get any material further up on the wall. Eventually the canister was connected through the three-way stopcock to a water filled inverted graduated cylinder and 50 mL of gas was collected. The gas was removed from the graduated cylinder using a 100 mL glass syringe and a thin flexible tube. The gas collected in the syringe was then bubbled through D6-acetone in an NMR tube, cooled with acetone / frozen acetone (-95° C.; acetone melting point), and analyzed by proton and carbon NMR. The NMR spectra showed dihydrogen with trace amounts of acetylene, and ethylene. The identities of the products were confirmed by their chemical shifts and coupling constants against authentic samples.

[0067] A large amount of carbon was present at the end of the hydrolysis. The solution was neutralized with about 18 mL of approximately 5.5N HCl. This final pH was around 2. The carbon suspension from the hydrolysis was transferred to a 500 mL graduated cylinder and allowed to settle. Supernatant was decanted to leave a more manageable volume of about 40 mL. This latter suspension was then separated by centrifugation and washed in the vial with 4 volumes of distilled water. The final top water layer was removed and then it was dried on high vacuum until a constant weight of 0.257 grams was achieved.Example 4: Mechanochemical Synthesis of Rubidium-Carbon Alloy

[0068] A “500 mL” (~400 mL internal volume) steel ball mill container was filled with 719.6 g tungsten carbide balls (12 Large (¾″ diameter)). The ball mill canister was brought into a dry box (glovebox) and was charged with 0.281 g high vacuum dried coconut charcoal (23.4 mmol, 2 eq). The canister was sealed shut except for the central plug, through which argon was allowed to enter the container and purge it. After being purged with argon for 1 minute and 15 seconds, 1 g of rubidium (11.7 mmol, 1 eq) was added from an ampule to the canister through a glass funnel with the assistance of a heat gun. A small amount (a few milligrams) of rubidium was lost to the surface of the funnel and ampule during transfer. The canister was purged again with argon for another minute before inserting the central plug (covered with poly(tetrafluoroethylene) resin tape). The point at which the lid meets the base of the canister was taped up with electrical tape for good measure. The canister was milled in an Across International PQ-N 2 planetary steel ball mill. The canister was milled for 20 cycles of: 47 minutes forward direction at 580 RPM (15 second pause); 23 minutes forward direction at 300 RPM (15 second pause); 47 minutes reverse direction at 580 RPM (15 second pause); and 23 minutes forward direction at 300 RPM (15 second pause). No strong vibrations were observed in the initials milling time. The milling was paused for about a minute during the first 15 second pause to gauge the temperature by hand. The canister was warm to the touch (~30-40° C.). It was again paused a few hours later at the end of a 23 min slow cycle and the temperature was found to be just above room temp. The milling was paused once more for an extra minute at the end of the last fast cycle to check temperature and the canister was found to be warm to the touch. The canister was almost back to room temperature as the milling finished. In total the canister was milled for 46 hours and 40 minutes. The canister was immediately brought into the dry box for work up. The material was found to be a uniform shiny metallic mass, harder than rubidium metal itself, primarily located on the wall in a ring about 1 cm from the base of the canister 0.409 g of material was removed from the canister and stored under argon. The material proved to be roughly the hardness of potassium metal and tarnished slowly in the atmosphere forming a black coating.

[0069] A small granule of material was transferred to a melting point capillary and topped with paraffin film wax to seal it. The granule had a shiny side and a slightly tarnished side. It was taken out of the dry box and placed in a melting point apparatus. There was no melting at the usual melting point of rubidium, 39° C. From 20-70° C. there was no observable change. As the sample went from 70-80° C. the piece became fully shiny. As it reached 200° C. the part leaning against the wall began to wet the glass, indicating the start of melting. As it continued heating the piece started wetting the glass more. Starting around 280° C. it began subliming around the tube forming a mirror-like coating which accelerated as the temperature increased. The piece retained its structural integrity even as it passed 400° C.

[0070] The residual Rb-C alloy in the milling jar was hydrolyzed as described above for the potassium-carbon alloy. The result indicated primarily dihydrogen as the gaseous product with trace acetylene and ethylene. A fine powdery form of carbon was released from the alloy after hydrolysis.INCORPORATION BY REFERENCE

[0071] All publications and patents mentioned herein are hereby incorporated by reference in their entirety as if each individual publication or patent was specifically and individually indicated to be incorporated by reference. In case of conflict, the present application, including any definitions herein, will control.EQUIVALENTS

[0072] While specific embodiments of the subject invention have been discussed, the above specification is illustrative and not restrictive. Many variations of the invention will become apparent to those skilled in the art upon review of this specification and the claims below.

[0073] The full scope of the invention should be determined by reference to the claims, along with their full scope of equivalents, and the specification, along with such variations.

Claims

1. A method of making an alkali metal-carbon alloy comprising:contacting a group 1 metal with a source of elemental carbon to form a precursor mixture; andapplying a mechanical force to the precursor mixture;thereby producing the alkali metal-carbon alloy.

2. The method of claim 1, wherein contacting the group 1 metal with the source of elemental carbon is conducted in the absence of a liquid (e.g., a solvent).

3. The method of claim 1, wherein applying the mechanical force comprises ball-milling the group 1 metal and source of elemental carbon.

4. The method of claim 1, wherein applying the mechanical force is carried out in a planetary ball mill reactor.

5. The method of claim 1, wherein the group 1 metal is sodium, potassium, rubidium, or caesium.

6. The method of claim 1, wherein the source of elemental carbon is selected from biochar, charcoal, graphite, carbon black, coal, diamond, a fullerene, coke, or a combination thereof.

7. The method of claim 1, wherein the mechanical force is applied to the precursor mixture under an inert atmosphere.

8. The method of claim 1, wherein the mechanical force is applied to the precursor mixture under an atmosphere of argon.

9. The method of claim 1, wherein the mechanical force is applied to the precursor mixture at a temperature from about −10° C. to about 120° C.

10. The method of claim 1, wherein the mechanical force is applied to the precursor mixture without external heating.

11. An alloy consisting of carbon and a group 1 metal.

12. The alloy of claim 11, wherein the group 1 metal is selected from sodium, potassium, rubidium, and caesium.

13. The alloy of claim 12, wherein the group 1 metal is sodium.

14. The alloy of claim 13, wherein the melting point of the alloy is greater than 180° C.

15. The alloy of claim 12, wherein the group 1 metal is potassium.

16. The alloy of claim 15, wherein the melting point of the alloy is greater than 400° C.

17. The alloy of claim 12, wherein the group 1 metal is rubidium.

18. The alloy of claim 17, wherein the melting point of the alloy is about 200° C.

19. The alloy of claim 12, wherein the group 1 metal is caesium.

20. The alloy of claim 11, wherein the group 1 metal has a neutral formal charge.

21. The alloy of claim 11, wherein the group 1 carbon has a neutral formal charge.

22. The alloy of claim 11, wherein the alloy is a solid at about 25° C. and about 1 atm.

23. The alloy of claim 11, the alloy is a solid solution, wherein the carbon is the solute and the group 1 metal is the solvent.

24. The alloy of claim 11, wherein the alloy comprises less than about 70 wt % carbon.

25. The alloy of claim 24, wherein the alloy comprises from about 1 wt % to about 50 wt % carbon.

26. The alloy of claim 11, wherein the alloy is conductive to electric current.

27. The alloy of claim 11, wherein the alloy is less malleable than the group 1 metal in elemental form.

28. The alloy of claim 11, wherein the alloy has a melting point greater than about 100° C.

29. The alloy of claim 11, wherein the group 1 metal is not intercalated between graphene or graphite layers.

30. The alloy of claim 11, wherein, when the alloy is contacted with a source of H+, dihydrogen, alkali metal cations, and a neutrally charged carbon allotrope are produced.

31. The alloy of claim 11, wherein, when the alloy is contacted with a source of H+, hydrocarbons are not produced.

32. The alloy of any one of claims 11-31, prepared according to the method of any one of claims 1-10.