KR20210011359A - Barium doped composite electrode material for fluoride ion electrochemical cells - Google Patents

Abstract

The present disclosure relates to a method for preparing core-shell and yoke-shell nanoparticles, and to an electrode comprising the same. Core-shell and yoke-shell nanoparticles and electrodes comprising them are suitable for use in electrochemical cells such as fluoride shuttle batteries. The shell may also prevent the metal core from oxidation, such as in electrochemical cells. In some embodiments, the electrochemically active structure includes a dimensionally changeable active material that forms particles that expand or contract upon reaction with or upon release of fluoride ions. One or more particles are at least partially surrounded by a fluoride conductive encapsulant, and optionally, one or more voids are formed between the active material and the encapsulant using a sacrificial layer or selective etching. The fluoride conductive encapsulant may include one or more metals. When an electrochemically active structure is used in a secondary battery, the presence of voids can accommodate a dimensional change of the active material.

Description

Barium doped composite electrode material for fluoride ion electrochemical cells

[Cross reference to related application]

This application is a US Patent Application No. 62/434,611 entitled "Composite Electrode Materials for Fluoride-Ion Electrochemical Cells" filed on December 15, 2016 and the invention filed on February 1, 2017. A US patent filed December 15, 2017 entitled "Composite Electrode Materials for Fluoride-Ion Electrochemical Cells" claiming priority to US Patent Application No. 62/453,295 entitled "Core Shell" Partial continuing applicant of Application No. 15/844,079, has priority to U.S. Patent Application No. 16/013,739, entitled "Barium-Doped Composite Electrode Materials for Fluoride Electrochemical Cells," filed June 20, 2018. Insist. U.S. Patent Application No. 16/013,739 also claims priority to U.S. Patent Application No. 62/676,693 entitled "Composite Electrode Materials for Fluoride-Ion Electrochemical Cells," filed May 25, 2018. . This application also claims priority to US Patent Application No. 62/676,693. Each of the foregoing applications is incorporated herein in its entirety by reference.

[Technical field]

The present disclosure relates to an electrochemically active material, and more particularly, to a fluoride ion battery system comprising an electrode material having a custom structure and composition to improve battery performance. More specifically, the present disclosure relates to core-shell nanoparticles, methods for making them, and their use in electrochemical cells.

Metal nanoparticles are highly desirable for use in a number of applications, including use as catalysts and electrode materials for batteries. However, the use of metal nanoparticles may be limited by system operating conditions or other factors. For example, fluoride shuttle batteries are of increasing interest as an alternative to lithium-ion batteries. However, due in part to the operating conditions detrimental to the many materials that may otherwise be included in the fluoride shuttle battery electrode, the materials available for use in fluoride shuttle battery systems are limited.

Fluoride ion batteries are electrochemical cells that operate through a fluoride mediated electrode reaction (i.e., often through a conversion-type reaction, the acceptance or release of fluoride ions at the electrode upon charging or discharging). Such electrochemical cells may provide greater energy density, lower cost and/or improved safety characteristics compared to lithium and lithium ion batteries. Fluoride ion systems, for example, with these electrodes in contact with a fluoride-conducting electrolyte in a solid state, during a charge-discharge cycle, fluoride ions are reversibly between the anode and the cathode. In US 7,722,993 to Potanin, which describes an embodiment of an exchanged secondary electrochemical cell, described in the solid state. Potanin is, the alkaline earth metals (alkaline-earth metal) fluoride / fluorides of _{(CaF 2, SrF 2, BaF} 2) and / or fluorides of alkaline metals (LiF, KF, NaF) and / or alkali metal chlorides (LiCl, KCl , NaCl), as well as a wide range of other compound fluorides, together with fluorides of La, Ce, or compound fluorides based on them. However, such electrochemical cells operate usefully only at temperatures above room temperature (eg, 150° C.) due to the limited conductivity of the solid state electrolyte.

Attempts have also been made to provide an electrochemical system based on fluoride ions that can use liquid electrolytes. For example, US 2011-0143219 A1 to Weiss et al. and US 9,166,249 to Darolles et al., fluorides selected to include a solvent-borne fluoride salt that is at least partially present in a dissolved state in an electrolyte. Disclosed is an ion battery configuration. However, for many applications, the chemical reactivity of the electrode material with the liquid electrolyte is important, and these liquid electrolyte systems do not provide sufficiently reliable high discharge and/or high capacity operation.

In the following, a simplified overview of one or more aspects of the present disclosure is provided to provide a basic understanding of such aspects. This summary is not a comprehensive overview of all contemplated aspects, is not intended to identify key or critical elements of all aspects, nor is it intended to describe the scope of any or all aspects. Its purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

In some embodiments, the present disclosure is directed to an electrochemically active structure comprising a core comprising an active material, and a fluoride-containing shell at least partially surrounding the active material, The fluoride-containing shell contains a first metal and a second metal, and the first metal is barium.

In some embodiments, the present disclosure relates to a method of making coated metal nanoparticles, the method comprising: a) providing a water/metal nanoparticle mixture; b) exposing the water/metal nanoparticle mixture to an inert atmosphere; And c) forming a fluoride-containing shell around the metal nanoparticle core, wherein the fluoride-containing shell comprises a first metal and a second metal, and the first metal is barium.

In some embodiments, the present disclosure relates to an electrode comprising a core comprising copper nanoparticles, and a fluoride-containing shell at least partially surrounding the copper nanoparticles, wherein the fluoride-containing shell comprises barium and lanthanum. in a ratio of x to 1-x, and as a result, the sum of the moles of barium and the moles of lanthanum in the empirical formula of the fluoride-containing shell is 1.

In some embodiments, the present disclosure relates to an electrochemically active structure comprising: a core comprising an active material and a fluoride-containing shell at least partially surrounding the active material, wherein the fluoride-containing shell comprises a first metal and a second A metal is included, and the first metal is a divalent or tetravalent metal cation.

These and other aspects of the invention will be more fully understood upon review of the detailed description that follows.

1A shows a cross-sectional view of a core-shell nanoparticle comprising a core comprising a metal nanoparticle and a shell comprising a metal halide or a metal oxyhalide in one aspect of the present disclosure.
1B schematically shows a general route to a "yolk-shell" composite using a sacrificial inorganic "middle" layer.
1C illustrates a route to a “yoke-shell” composite using a sacrificial polymer “intermediate” layer.
1D shows an alternative route to the “yoke-shell” composite in the absence of a sacrificial “intermediate” layer.
1E depicts a change to the "sacrificial" synthesis of a "york-shell" composite, in which nanoparticles of an active material are to be grown on the surface of the "sacrificial" material.
1F schematically shows the growth of active material in pores or internal structures of preformed "sacrificial" material.
1G schematically shows the growth of the active material in the pores or internal structures of a preformed “sacrificial” material, where the shell constituents are selected to be electrochemically inert at the electrochemical reaction potential of interest.
2 is a schematic illustration of a fluoride ion electrochemical cell in one aspect of the present disclosure.
3 shows the XRD spectrum of the separated copper nanoparticles of Comparative Example 1, without shell, immediately after synthesis and separation ("as-made").
FIG. 4 shows a stacked XRD spectrum of the separated copper nanoparticles of Comparative Example 1, without shell, during manufacture and after exposure to air for 4 and 9 days.
5 shows an XRD spectrum of Cu-LaF ₃ core-shell nanoparticles of Experimental Example 1 as synthesized in one aspect of the present disclosure.
6 shows stacked XRD spectra of Cu-LaF ₃ core-shell nanoparticles of Experimental Example 1 after exposure to air for 9, 16, and 23 days.
7A and 7B are transmission electron microscopy (TEM) images of Cu-LaF ₃ core-shell nanoparticles of Experimental Example 1 during preparation.
8A shows a high-resolution TEM image of Cu-LaF ₃ core-shell nanoparticles of Experimental Example 1, showing Cu (core) and LaF ₃ (shell) regions. 8B and 8C show zoomed-out images of the same nanoparticles.
9 is a schematic diagram of an example of a fluoride ion electrochemical cell including Cu-LaF ₃ core-shell nanoparticles of Experimental Example 1 as an active material in a negative electrode (anode) in one aspect of the present disclosure.
10A is a plot of voltage as a function of specific capacity for electrochemical testing of a half cell battery containing Cu-LaF ₃ core-shell nanoparticles of Experimental Example 1 as an active material in an electrode in an embodiment of the present disclosure to be.
10B is an X-ray diffraction spectrum of the electrode of the half cell battery test of FIG. 10A measured under initial conditions, after discharge, and after charging.
11 shows the XRD spectrum of the nanoparticles of Comparative Example 2 during synthesis.
12 shows stacked XRD spectra of nanoparticles of Comparative Example 2 after exposure to air for 8 days, 15 days, and 22 days.
13 is a TEM image of the nanoparticles of Comparative Example 2 showing the non-uniform partial coating of copper nanoparticles by LaF ₃ as well as LaF ₃ not related to the copper nanoparticles.
14 shows the composition of LaF ₃ /Cu and Cu thin films and cyclic voltammetry data.
15A shows a cyclic voltammogram of a LaF ₃ /Cu bilayer thin film. 15B and 15C are x-ray photoelectron spectroscopy (XPS) data for C, La, O, F, and Cu at various lengths of etching time at voltages 1 and 2 shown in FIG. 15A. Shows.
16 shows a schematic representation of Cu@LaF ₃ and Cu@Ba _x La _1-x F _3-x nanoparticles in accordance with some aspects of the present disclosure.
17A shows an example of a scanning electron microscopy (SEM) image of Cu@La _0.97 Ba _0.03 F _2.97 in accordance with some aspects of the present disclosure.
17B and 17C show examples of transmission electron microscopy (TEM) images of Cu@La _0.97 Ba _0.03 F _2.97 in accordance with some aspects of the present disclosure.
17D shows an example of an energy dispersive x-ray (EDX) image of Cu@La _0.97 Ba _0.03 F _2.97 in accordance with some aspects of the present disclosure. 17E to 17H show component Cu, F, La and Ba image maps, respectively.
18A-18D illustrate x-ray photoelectron spectroscopy (XPS) spectra for Cu@La _0.97 Ba _0.03 F _2.97 in accordance with some aspects of the present disclosure.
19 shows XRD spectra for Cu@LaF ₃ and Cu@La _0.97 Ba _0.03 F _2.97 in accordance with some aspects of the present disclosure.
20A is a voltage profile of an initial charge-discharge cycle of a Cu@LaF ₃ electrode or a Cu@Ba _x La _1-x F _3-x electrode compared to an Ag/Ag ⁺ reference electrode, according to some aspects of the present disclosure. Shows.
20B shows a comparison of the dose achieved for Cu@LaF ₃ and for Cu@La _0.97 Ba _0.03 F _2.97 , according to some aspects of the present disclosure.
FIG. 20C shows an XRD spectrum of Cu@La _0.97 Ba _0.03 F _2.97 in an initial state and after initial charge and subsequent initial discharge, in accordance with some aspects of the present disclosure.
20D shows an XRD spectrum of Cu@LaF ₃ in an initial state and after initial charge and subsequent initial discharge, in accordance with some aspects of the present disclosure.

The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations, and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description contains specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some cases, well-known components are shown in block diagram form in order to avoid obscuring such concepts.

In general, the present disclosure is directed to a fluoride ion battery system comprising an electrochemically active material and an electrode material having a custom structure and composition to improve battery performance. In some embodiments, the present disclosure relates to core-shell nanoparticles, devices incorporating core-shell nanoparticles, as well as methods of making and using core-shell nanoparticles and devices comprising core-shell nanoparticles.

Primary and secondary electrochemical cells such as batteries, utilizing fluoride ion charge carriers, active electrode materials, and suitable liquid electrolytes, can provide an alternative to prior state of the art lithium batteries and lithium ion batteries. Such a fluoride-ion battery (FIB) system can operate usefully at room temperature while utilizing the fluoride anion contained in the liquid electrolyte as at least part of the charge carrier in the electrochemical cell. The FIB system has an anode and a cathode that are physically separate from each other, but in common contact with a fluoride ion conducting electrolyte. The anode is typically a low potential element or compound and may be a metal, a metal fluoride, or an intercalating composition. Similarly, the cathode may be an element or composition, and may be a metal, metal fluoride, or intercalation composition having a higher potential than the anode. Fluoride ions (F ⁻ ) in the fluoride conductive electrolyte migrate from the cathode to the anode during discharge and from the anode to the cathode during charging of the battery:

Discharge:

Anode: MF _x + nF- → MF _x+n + ne- (acceptance of fluoride ions, oxidation)

Cathode: MF _y + ne- → MF _yn + nF- (fluoride ion release, reduction)

During charging, a reverse reaction occurs.

For example, the FIB cell reaction based on the fluoride anion transfer between Ca and Cu, a metal that can both form a metal fluoride, might be:

Discharge:

Ca + CuF ₂ → CaF ₂ + Cu

charge:

CaF ₂ + Cu → Ca + CuF ₂

There are two major challenges to enable stable and reliable long-term cycling of FIB electrodes. First, the reversibility of the electrochemical reaction is observed when the metal or metal fluoride active material is nano-sized (that is, when at least one of the particle size dimensions is less than 1 μm). However, having the particles of high surface energy having such small dimensions, the electrolyte component (for example, F ^-) and the often reaction, self-discharge "(i.e., the common current is that M + nF not ^- → like MF _n will provide undesirable side reactions including the reaction) is, when desired is needed (that is, during electrochemical charging or discharging) F ^-. coating to while still allowing the passage of ions encapsulate the active material particles, the shell , The formation of layers or etc. The encapsulating material can also protect the active material from side reactions, enabling long-term cycling stability of these electrode materials.

Second, such an electrochemical reaction is a conversion process in which the structure of a metal or metal fluoride is destroyed during the electrochemical process and is modified as a metal fluoride or metal respectively during the process. This conversion process results in a significant volume change between the state of charge and the state of discharge of the active material, as shown by the example given in Table 1 below:

Table 1: Volume change for the conversion of metal to metal fluoride

Such significant volume changes limit the usefulness of a conformal protective coating to encapsulate particles of the FIB electrode material, due to the volume change, one particular state of charge is not necessarily conformal to the particle in different states of charge. Because it won't be (conformal). What is needed is a change in the volume of the active material during charging and discharging while allowing ionic conduction through the encapsulant, protecting the electrode active material from side reactions with the electrolyte, and not allowing direct contact between the active material and the electrolyte. A composition and process that has sufficient void space in the encapsulant and/or encapsulant expansion/contraction properties to accommodate. In some embodiments, the sufficient void space may be a no void space. Such compositions and their preparation are schematically shown below.

As used herein, the term “about” is defined as close to what is understood by one of ordinary skill in the art. In one non-limiting embodiment, the term “about” is defined as being within 10%, preferably within 5%, more preferably within 1%, and most preferably within 0.5%.

In some embodiments as shown in FIG. 1A, the core-shell nanoparticles comprise a core comprising a metal or metal alloy (“Me”) and a shell comprising a metal halide or metal oxyhalide. The metal of the core may be the same as the metal of the metal halide shell. In some embodiments, the metal of the core and the metal of the metal halide or metal oxyhalide shell are different metals. In some embodiments, the metal halide shell itself may comprise two metals. The core-shell nanoparticles of the present disclosure may be incorporated into a variety of methods and applications, including, but not limited to, electrodes for use in electrochemical cells, including fluoride shuttle batteries as shown in FIG. 2. have.

Metals or metal alloys used to form the core include, but are not limited to, iron nanoparticles, cobalt nanoparticles, nickel nanoparticles, copper nanoparticles, lead nanoparticles, and alkaline earth metal nanoparticles. In a preferred embodiment, the metal nanoparticles are selected from the group consisting of cobalt nanoparticles and copper nanoparticles. In another preferred embodiment, the metal nanoparticles are copper nanoparticles. The metal used to form the core may be synthesized by mixing a metal precursor solution with a reducing agent to form metal nanoparticles.

In some embodiments, the metal nanoparticles used to form the core may be synthesized in the presence of a stabilizer that prevents or otherwise inhibits oxidation of the metal nanoparticles during synthesis, and the metal halide or metal oxy It can be easily removed from the metal nanoparticles prior to formation of the halide shell. For example, bulky polymers such as polyvinylpyrrolidone (molecular weight of 55,000 g/mol) used during metal nanoparticle synthesis inhibit oxidation of metal nanoparticles. However, such stabilizers cannot be easily removed from metal nanoparticles following synthesis. Without wishing to be bound by any particular theory, the residual stabilizer may provide an additional layer between the core formed by the metal nanoparticles and the metal halide or oxyhalide shell that impairs the performance of the core-shell nanoparticles in the desired system. Can be formed. For example, it is desirable to maintain the conductivity of core-shell nanoparticles used as an electrode material in an F-Shuttle battery. However, a core-shell material comprising an additional residual stabilizer layer between the core and the shell will likely appear as an increased space between the electrode materials; An additional layer of residual stabilizer and/or the resulting increased spacing may reduce the conductivity of the core-shell material. Without wishing to be bound by any particular theory, an additional layer of stabilizer may interfere with the contact between the core and the shell, which will conduct fluoride ions, while the absence of the stabilizer will not conduct fluoride ions from the core to the shell. It can also increase the likelihood.

Therefore, in the synthesis of the metal nanoparticles used to form the core, it is easy from the core to minimize the amount of stabilizer on the surface of the core prior to forming the metal halide or metal oxyhalide shell directly on the core. Removable stabilizers may also be used. In a non-limiting example, one or more stabilizers that may be used in the synthesis of metal nanoparticles are less than 1000 g/mol, optionally less than 500 g/mol, optionally less than 375 g/mol, and optional Includes molecular weights (individual or weight average) of less than 350 g/mol. Illustrative examples include hexadecyltrimethylammonium bromide (CTAB) having a molecular weight of 364 g/mol, citric acid having a molecular weight of 192 g/mol, and mixtures thereof.

In some embodiments, the shell of the core-shell nanoparticles is a metal salt solution and a halide that reacts with the separated metal nanoparticles used to form the core, for example, to form a metal halide shell on the core. It may also be formed by mixing with a salt solution. The shell may be deposited directly on the metal core and completely surround the core as shown in FIG. 1A. In some embodiments, the metal salt used to form the shell is selected from the group consisting of alkali metal salts, alkaline earth metal salts, and transition metal salts. In certain embodiments, the metal salt used to form the shell is a transition metal salt. In certain embodiments, the metal salt used to form the shell is selected from the group consisting of lanthanum salt, cerium salt, and magnesium salt. In certain embodiments, the metal salt used to form the shell is selected from the group consisting of lanthanum salts and cerium salts. In certain embodiments, the metal salt is a lanthanum salt. In a preferred embodiment, the lanthanum salt is lanthanum nitrate. In some embodiments, the halide salt is sodium fluoride. In a non-limiting example, the shell comprises a metal fluoride or metal oxyfluoride containing material (ie, CeF ₃ , CeOF, LaOF, LaF ₃ ).

In some embodiments, the metal salt solution comprises two metal salts. In some such embodiments, one of the two metal salts is a barium salt. In some embodiments, the metal salt solution includes a barium salt and a lanthanum salt. In some embodiments, the metal salt solution includes barium nitrate and lanthanum nitrate. In some embodiments, the metal salt solution comprises barium nitrate and lanthanum nitrate in a ratio of about 1:10.

In another embodiment, the core (or electrode active material) may be separated from the shell (or encapsulant) by a void space. The composition and process according to such an embodiment may protect the electrode active material from side reactions with the electrolyte, may allow ion conduction through the encapsulant, and charge and discharge without allowing direct contact between the active material and the electrolyte. The encapsulant may have sufficient void space and/or encapsulant expansion/contraction properties to accommodate the volume change of the active material during the period.

The English core and electrode active materials are used interchangeably herein. Similarly, the terms shell and encapsulant are used interchangeably herein.

In another embodiment, the present disclosure relates to an electrode comprising the core-shell nanoparticles disclosed herein. All aspects and embodiments described in connection with the core-shell nanoparticles and their manufacturing methods apply to the electrode with the same force. In a non-limiting example, the electrode is part of an F-shuttle battery system.

In some embodiments, the present disclosure relates to an electrochemically active structure comprising: a core comprising an active material and a fluoride-containing shell at least partially surrounding the active material, wherein the fluoride-containing shell comprises a first metal and a second Metal, and the first metal is barium. All aspects described in connection with the above-described embodiment apply to this embodiment with the same force, and vice versa.

In some embodiments, the active material comprises metal nanoparticles selected from iron nanoparticles, cobalt nanoparticles, nickel nanoparticles, copper nanoparticles, lead nanoparticles, and alkaline earth metal nanoparticles.

In some embodiments, the active material includes copper nanoparticles.

In some embodiments, the fluoride containing shell is attached directly to the core.

In some embodiments, the fluoride-containing shell is spaced from the core to define a void space therebetween.

In some embodiments, the second metal is lanthanum.

In some embodiments, barium and lanthanum are present in a ratio of x to 1-x, so that the sum of moles of barium and moles of lanthanum in the empirical formula of the fluoride containing shell is 1.

In some embodiments, x is about 0.03 to about 0.15.

In some embodiments, x is about 0.03.

In some embodiments, the present disclosure relates to a method of making coated metal nanoparticles, the method comprising: a) providing a water/metal nanoparticle mixture; b) exposing the water/metal nanoparticle mixture to an inert atmosphere; And c) forming a fluoride-containing shell around the metal nanoparticle core, wherein the fluoride-containing shell comprises a first metal and a second metal, and the first metal is barium. All aspects described in connection with the above-described embodiment apply to this embodiment with the same force, and vice versa.

In some embodiments, the metal nanoparticles include iron nanoparticles, cobalt nanoparticles, nickel nanoparticles, copper nanoparticles, lead nanoparticles, or alkaline earth metal nanoparticles.

In some embodiments, the metal nanoparticles comprise copper nanoparticles.

In some embodiments, the fluoride containing shell is attached directly to the core.

In some embodiments, the fluoride-containing shell is spaced from the core to define a void space therebetween.

In some embodiments, the second metal is lanthanum.

In some embodiments, barium and lanthanum are present in a ratio of x to 1-x, so that the sum of moles of barium and moles of lanthanum in the empirical formula of the fluoride containing shell is 1.

In some embodiments, x is about 0.03 to about 0.15.

In some embodiments, forming the fluoride-containing shell comprises adding a first metal salt, a second metal salt, and a fluoride-containing salt to the water/metal nanoparticle mixture to create a fluoride-containing shell around the metal nanoparticle core. However, the first metal is a barium salt.

In some embodiments, the second metal is a lanthanum salt.

In some embodiments, the first metal salt is barium nitrate and the second metal salt is lanthanum nitrate.

In some embodiments, barium nitrate and lanthanum nitrate are used in a molar ratio of about 1:10.

In some embodiments, the present disclosure relates to an electrode comprising a core comprising copper nanoparticles, and a fluoride-containing shell at least partially surrounding the copper nanoparticles, wherein the fluoride-containing shell contains barium and lanthanum x to 1 in the ratio of -x, and as a result, the sum of the moles of barium and the moles of lanthanum in the empirical formula of the fluoride-containing shell is 1. All aspects described in connection with the above-described embodiment apply to this embodiment with the same force, and vice versa.

In some embodiments, x is about 0.03 to about 0.15.

In some aspects, the present disclosure relates to a fluoride shuttle battery comprising an electrode and a liquid electrolyte.

In some embodiments, the present disclosure relates to an electrochemically active structure comprising: a core comprising an active material and a fluoride-containing shell at least partially surrounding the active material, wherein the fluoride-containing shell comprises a first metal and a second Metal, and the first metal is a divalent or tetravalent metal cation. All aspects and embodiments described in connection with the above-described embodiment apply to this embodiment with the same force, and vice versa. The fluoride-containing shell may be doped with barium (i.e., make a barium doped shell) or can be doped with any possible divalent or tetravalent metal cations (i.e., divalent metal cation doped shell or tetravalent metal cation doped. Make a shell); In other words, doping is not limited to doping with barium.

"Inert atmosphere" refers to a gas mixture that contains little or no oxygen and contains an inert or non-reactive gas or gases having a high threshold before reacting. The inert atmosphere may be, but is not limited to, an inert gas such as molecular nitrogen or argon, or a mixture thereof.

A “reducing agent” is a substance that causes the reduction of another material while itself being oxidized. Reduction refers to the gain of electron(s) by a chemical species, and oxidation refers to the loss of electron(s) by a chemical species.

A “metal salt” is an ionic complex in which the cation(s) are positively charged metal ion(s) and the anion(s) are negatively charged ion(s). “Cationic” refers to positively charged ions, and “anionic” refers to negatively charged ions. In the “metal salt” according to the present disclosure, the anion may be any negatively charged chemical species. Metals in the metal salt according to the present disclosure may include alkali metal salts, alkaline earth metal salts, transition metal salts, aluminum salts, or post-transition metal salts, and hydrates thereof, However, it is not limited to these.

An “alkali metal salt” is a metal salt in which the metal ion is an alkali metal ion or a metal of Group I of the periodic table of the elements, such as lithium, sodium, potassium, rubidium, cesium, or francium.

“Alkaline earth metal salt” is a metal salt wherein the metal ion is an alkaline earth metal ion, or a group II metal of the periodic table of the elements, such as beryllium, magnesium, calcium, strontium, barium, or radium.

A “transition metal salt” is a metal salt in which the metal ion is a transition metal ion, or a metal in the d block of the periodic table of the elements, including lanthanide and actinide series. Transition metal salts are scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, silver, cadmium, lanthanum, Cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium (thulium), ytterbium (lutetium), hafnium (hafnium), tantalum (tantalum), tungsten, rhenium (rhenium), osmium (osmium), iridium (iridium), platinum (platinum), gold, mercury, Actinium, thorium, protactinium, uranium, neptunium, plutonium, americium, curium, berkelium, californium, einsteinium einsteinium), fermium, mendelevium, nobelium, and salts of lawrencium.

"Post-transition metal salt" is a metal salt in which the metal ion is a post-transition metal ion, such as gallium, indium, tin, thallium, lead, bismuth, or polonium.

"Halide salt" means a halide in which the anion(s) includes, but is not limited to, fluoride ion(s), chloride ion(s), bromide ion(s), iodide ion(s). It is an ionic complex that is an ion(s). A “fluoride salt” is an ionic complex in which the anion(s) are fluoride ion(s). According to the present disclosure, the cation of the halide salt or fluoride salt may be any positively charged chemical species.

A “metal fluoride” is an ionic complex in which the cation is one or more metal ion(s) and the anion(s) is fluoride ion(s). According to some aspects of the present disclosure, the metal salt(s) and fluoride salt react to form a metal fluoride shell around the metal nanoparticle core. Similarly, a “metal halide” is an ionic complex in which the cation is one or more metal ion(s) and the anion(s) is halide ion(s).

"Fluoride-containing" salts are ionic complexes in which the anion(s) contain fluoride ions, but are not limited to being fluorides by themselves. Instead, “fluoride-containing” salts include ionic complexes in which the anion(s) contains the fluoride itself in a complex with another ion or atom. "Fluoride-containing" salts suitable for use in aspects of the present disclosure include fluoride salts, non-metal fluoroanions such as tetrafluoroborate salts and hexafluorophosphate salts. , And oxyfluoride salts, including, but not limited to, those known to those of ordinary skill in the art. In some aspects of the present disclosure, the fluoride containing salt may include quaternary ammonium fluoride and a fluorinated organic compound. According to some aspects of the present disclosure, the metal salt and the fluoride-containing salt react to form a fluoride-containing shell around the metal nanoparticle core.

The term “electrode” refers to an electrical conductor in which ions and electrons are exchanged with an electrolyte and an external circuit. “Positive electrode” and “cathode” are used synonymously in this description and refer to an electrode having a higher (ie, higher) electrode potential in an electrochemical cell. “Negative electrode” and “anode” are used synonymously in this description and refer to an electrode having a lower (ie, lower) electrode potential in an electrochemical cell. Cathodic reduction refers to the gain of the electron(s) of the chemical species, and anode oxidation refers to the loss of the electron(s) of the chemical species. The positive and negative electrodes of the present invention may be provided in a range of various types of useful configurations and form factors as known in the field of electrochemistry and battery science, including thin electrode designs such as thin film electrode configurations. have. Electrodes are, for example, US Patent No. 4,052,539 and Oxtoby et al., [Principles of Modern Chemistry (1999), pp. 401-443], including those described in the art.

The term “electrochemical cell” refers to a device and/or device component that converts chemical energy into electrical energy and vice versa. An electrochemical cell has two or more electrodes (eg, a positive electrode and a negative electrode) and an electrolyte, wherein the electrode reaction occurring at the electrode surface results in a charge transfer process. Electrochemical cells include, but are not limited to, primary batteries, secondary batteries, and electrolysis systems. General cells and/or battery configurations are known in the art (see, for example, Oxtoby et al., Principles of Modern Chemistry (1999), pp. 401-443).

“Electrolyte” refers to an ionic conductor, which may be in a solid state, a liquid state (most common), or more rarely a gas (eg, plasma).

I. Core-shell nanoparticles comprising a metal core and a metal halide or metal oxyhalide shell

In one embodiment, core-shell nanoparticles are provided comprising a metal core surrounded by a metal halide or metal oxyhalide shell.

In an illustrative example, core-shell nanoparticles may be included in the electrodes of a rechargeable battery, such as an F-shuttle battery. For example, it is difficult to use metal nanoparticles in the electrodes of an F-shuttle battery because the metal is exposed to conditions leading to undesirable oxidation or melting of the metal. Thus, a halide shell is provided that is tailored to protect the metal core nanoparticles from the environment of the electrode, while maintaining the desired performance of the metal nanoparticles. In a non-limiting example, the core may comprise copper metal and the shell may comprise LaF ₃ . In another non-limiting example, the core may comprise copper metal, and the shell may comprise Ba _x La _1-x F _3-x .

A method of preparing core-shell nanoparticles includes providing a first mixture comprising metal nanoparticles and a reducing agent, and mixing the first mixture with a solution comprising one or more metal salts and halide salts to obtain metal nanoparticles. It may also include forming a metal halide or oxyhalide shell on the particles. In a non-limiting example, the solution includes a metal salt and a halide salt. In another non-limiting example, the solution includes two metal salts and halide salts. In some such examples, one of the two metal salts is a barium salt. In another such example, the two metal salts include a barium salt and a lanthanum salt.

I(a). Synthesis and separation of metal cores

In general, metal nanoparticles for use as metal cores may also be synthesized by reacting a metal salt solution with a reducing agent in the presence of one or more stabilizers. In an illustrative example, the metal salt solution includes copper (II) nitrate hemipentahydrate (Cu(NO ₃ ) ₂ ·2.5H ₂ O) as the metal salt. The metal salt is mixed with CTAB and water, and the pH of the mixture may be adjusted to a pH of about 10 to 11 using, for example, ammonium or sodium hydroxide.

Prior to addition of the reducing agent to the metal salt solution, the reducing agent may be mixed with one or more stabilizers and water, or before being combined with the metal salt solution, may be mixed for a period of time such as 20 minutes. The reducing agent is hydrazine, sodium borohydride, sodium cyanoborohydride, sodium dithionate, sodium dithionite, iron (II) sulfate (iron (II) sulfate), tin (II) chloride, potassium iodide, oxalic acid, formic acid, ascorbic acid, thio It is selected from the group consisting of a thiosulfate salt, a dithionate salt, a phosphorous acid, a phosphite salt, and a hypophosphite salt. In a preferred embodiment, the reducing agent is hydrazine.

The metal salt solution and the reducing agent are combined to form metal nanoparticles. The synthesis of metal nanoparticles is carried out in an oxygen-free atmosphere. Illustrative examples of an oxygen-free atmosphere include, but are not limited to, nitrogen, argon, helium, hydrogen, and mixtures thereof. Following synthesis, the metal nanoparticles are separated from the synthesis solution. It is to be understood that the method of separating the metal nanoparticles is not limited and may include one or more techniques such as filtering, decanting, and centrifugation. The metal nanoparticles may be washed one or more times with a solvent such as ethanol to remove any residual stabilizers or other organic materials from their surface.

I(b) shell formation

In general, the separated metal nanoparticles may be redispersed in an aqueous solution containing an additional reducing agent in an oxygen-free atmosphere. Then, the mixture containing the separated metal nanoparticles and a reducing agent is mixed with a metal salt solution and a halide salt solution used to form a metal halide shell on the metal nanoparticle core in an oxygen-free atmosphere. The metal salt solution and fluoride salt solution used to form the shell may be sequentially added to the nanoparticle mixture, or the metal salt solution and fluoride salt solution used to form the shell may be added simultaneously to the nanoparticle mixture. have. In some embodiments, the metal salt solution comprises a single metal salt. In another embodiment, the metal salt solution comprises two metal salts. In some such embodiments, the metal salt solution includes a barium salt. In some such embodiments, the metal salt solution includes a barium salt and a lanthanum salt. In some such embodiments, the metal salt solution includes barium nitrate and lanthanum nitrate. In some such embodiments, the metal salt solution comprises barium nitrate and lanthanum nitrate in a ratio of about 1:10.

II "Yoke-Shell" nanoparticles

(i) protective fluoride ion conductive coating

Useful protective encapsulation coatings include a fluoride-ion conducting phase that is chemically and electrochemically stable in the presence of a liquid FIB electrolyte. Such a phase allows the exchange of F- between the electrolyte and the active material. Suitable phases are known in the art and are, for example, ["The CRC Handbook of Solid State Electrochemistry", Chapter 6 (CRC, 1997, PJ Gellings and HJM Bouwmeester, Eds.)], [Sorokin and Sobolev, Crystallography Reports 2007]. , 52, 5, 842-863], [Sobolev et al., Crystallography Reports 2005, 50, 3, 478-485], and [Trnovcova et al., Russian Journal of Electrochemistry, 2009, 45, 6, 630-639]. Is explained. These are, for example, a crystalline phase, such as LaF ₃ , CaF ₂ , SnF ₂ , PbF ₂ , PbSnF ₄ , similar doped and/or solid solution phases (e.g. La _0.9 Ba _0.1 F _2.9 , Ca _0.8 Y _0.2 F _2.2 , Ca _0.5 Ba _0.5 F ₂ , and Pb _0.75 Bi _0.25 F _2.25 ), glassy phase such as 35InF ₃ 30SnF ₂ 35PbF ₂ , and mixed fluoride/other anionic phases such as LaOF do. For the purposes of this disclosure, any material or phase that allows the exchange of F- between the electrolyte and the active material, having a bulk ionic conductivity greater than 10-10 S/cm at 298K, is within the scope of the present invention. These phases, along with components selected to be electrochemically stable at the potential required for the reaction of the species contained in the coating by taking into account the standard redox potentials of the internal species and the shell components available in the standard text. Is selected. For a more detailed discussion of the selection of coating components in this regard, see the example of FIG. 1G.

Alternative protective coatings are polymers that are conductive to fluoride ions, for example borate-functionalized polymers, alkylammonium-functionalized polymers, or [Gorski et al., Anal. Chim. Acta 2009, 633, 181-187] and [Gorski et al., Anal. ChimActa 2010, 665,39-46].

The thickness of the protective coating can be achieved at an appropriate operating rate (e.g., a C rate corresponding to complete charging or discharging of the energy stored in the electrochemical cell within 1 hour) at around 298 K for charging/discharging of the electrochemical cell. The F- exchange between the electrolyte and the active material is chosen to occur on a timescale that allows it to occur and will depend on the ionic conductivity of the coating material or phase. For example, a coating of LaF ₃ or Ba _x La _1-x F _3-x may have a thickness between 1 and 200 nm, such as between about 5 nm and about 20 nm, or any integer therebetween or It is most useful to be a subrange. More generally, the coating thickness can be from about 1 nm to about 1 μm.

및 Kemnitz, Dalton Trans., 2008, 1117-1127] 및 [Fujihara 등등, J. Ceram. Soc. Japan, 1998, 106, 124-126]에서 설명되는 것과 유사한 졸-겔 합성이다. 코팅은, 제조시, 옵션 사항으로, 소망에 따라, 어닐링 단계를 위해 공기 또는 Ar과 같은 불활성 가스 중 어느 하나에서 상승된 온도에 노출될 수도 있다. 예를 들면, 졸-겔법에 의해 제조되는 LaF₃ 코팅은, 코팅을 어닐링하고 용매와 같은 불순물의 제거를 보조하기 위해, 공기 중에서 500 ℃까지 가열될 수도 있다. 이러한 방식으로, 플루오르화물 전도성 코팅 상(fluoride-conducting coating phase)은, 프리커서 재료, 그들의 화학량론적 비율, 및 초기 반응후 어닐링 단계(post-initial reaction annealing step)를 조정하는 것에 의해 소망에 따라 합성될 수도 있다. LaF₃ 코팅의 이러한 졸-겔 합성은 또한, 기술 분야에서 통상의 지식을 가진 자에게 공지되어 있는 방법에 의해, Ba_xLa_1-xF_3-x의 코팅을 제조하도록 수정될 수도 있다.The coating can be made by any suitable synthetic method. These include precipitation of solids from solutions containing fluorides or their constituent precursors, sol-gels or other soft chemical materials or "chimie douce" methods, hydrothermal synthesis, vacuum methods such as chemical vapor deposition, Solution chemical material technologies such as the formation of coatings by physical vapor deposition, sputtering, laser ablation and molecular beam epitaxy, electrochemical deposition, or fluorination of the material after deposition by reaction with a fluorine source. chemistry technique). For example, one preferred method for the preparation of a LaF ₃ coating is using a soluble lanthanum and fluorine source in a suitable solvent (e.g., La(CH ₃ COO) ₃ and CF ₃ COOH in water), [

And Kemnitz, Dalton Trans., 2008, 1117-1127] and Fujihara et al., J. Ceram. Soc. Japan, 1998, 106, 124-126] is a sol-gel synthesis similar to that described. The coating may, in manufacturing, optionally, if desired, be exposed to elevated temperatures in either air or an inert gas such as Ar for the annealing step. For example, a LaF ₃ coating prepared by the sol-gel method may be heated to 500° C. in air to anneal the coating and aid in the removal of impurities such as solvents. In this way, the fluoride-conducting coating phase can be synthesized as desired by adjusting the precursor materials, their stoichiometric ratios, and the post-initial reaction annealing step. May be. This sol-gel synthesis of LaF ₃ coatings may also be modified to prepare coatings of Ba _x La _1-x F _3-x , by methods known to those of ordinary skill in the art.

In another example, the LaF ₃ coating can be obtained from precipitation by slowly adding NH ₄ F to an aqueous La(NO ₃ ) ₃ solution in which the nanoparticles of the core material are suspended. Since LaF ₃ is very insoluble in water, its crystallization will begin on the surface of the suspended nanoparticles. The precipitation synthesis of the LaF ₃ coating may also be modified to produce a coating of Ba _x La _1-x F _3-x , by methods known to those of ordinary skill in the art.

Alternatively, a La ₂ O ₃ coating can be prepared using a sol-gel approach, followed by post-fluorination with F ₂ or HF, resulting in a significant portion of this oxide being LaOF and/or You can switch to LaF ₃ . This sol-gel approach may also be used to prepare coatings of Ba _x La _1-x F _3-x by methods known to those of ordinary skill in the art.

The fluoride conductive encapsulant and/or coating phase and material may be a three-dimensional structure (e.g., metal or metal fluoride nanoparticles, or an aggregate of nanoparticles), a two-dimensional structure (e.g., metal or Metal fluoride thin film), or a one-dimensional structure (eg, fibers or tubes of metal or metal fluoride). Similarly, the fluoride conducting phase may be fabricated on the exterior and/or interior surfaces of complex micro or mesoporous structures, such as zeolites or highly ordered template materials. This may include, but is not limited to, mesoporous silica, such as MCM-41 or SBA-15, or a metal organic framework or similar coordination polymer.

(ii) Active material encapsulated in fluoride ion conductive coating

Useful structures and compositions include between a metal and a metal fluoride phase (or between a lower valence metal fluoride species (MFm) and a higher valency metal fluoride species (MFn), where n> m for the same metal (M)). ) A metal or metal fluoride is encapsulated in a fluoride ion conductive coating (as described in (i) above) so that there is sufficient void space within the encapsulation to accommodate volume change upon conversion without rupture of the coating or material. do. Such structures and compositions are sized to fit within the fluoride conductive encapsulant, in some cases having at least sufficient void space available to convert up to 100% of the encapsulated metal atoms into the appropriate metal fluoride phase (e.g., In the case of the process Fe → FeF ₃ , from Table 1, at least 211% of the void space is required compared to the starting volume of Fe. In other cases, the degree of conversion is sufficient void space to achieve 100% conversion. In the absence of this, it may be electrochemically controlled (eg, by controlling the voltage limit and/or charge/discharge capacity) so that the encapsulant does not burst during cycling.. Also, the fluoride conductive encapsulant is conformal or metallic or metallic. Structures and compositions are also contemplated that have insufficient void space to fully accommodate the conversion of from to metal fluoride, but with adequate flexibility for stretching or shrinking without rupture or cracking of the encapsulant, such compositions as desired. It may be two-dimensional (eg, film-void-coating), or three-dimensional (eg, nanoparticle-void-coating, or more complex arrangements such as metal-impregnated zeolite-void-coating).

In still other embodiments, multiple concentrically arranged encapsulants are contemplated. Each concentrically arranged encapsulant may be separated by voids, and may be composed of the same or different materials. In still other embodiments of concentrically arranged encapsulants, the active material and the outermost encapsulant (in contact with the electrolyte) can allow the passage of fluoride ions and dimensional change in volume during cycling while rupturing the outermost encapsulant. It may be separated by a polymer or other flexible material that can be accommodated.

As will be appreciated, an active material completely enclosed within and disposed within the encapsulant, but having at least some remaining void space and/or a compressible non-active material (eg, polymer) will be referred to as a “yoke-shell” nanocomposite structure. I can. Such fully encapsulated structures can be based on various compositional arrangements of active material and fluoride conductive encapsulant. However, other arrangements are also contemplated including an active material that is only partially surrounded by a fluoride conductive protective coating. Such a structure may be a two-dimensional or three-dimensional non-fluoride conductive support structure (e.g., film, open sided cell) containing an active material having one or more sides coated with a fluoride conductive material to allow ion transport. cell), tube, or the like). Such support structures may include void spaces or dimensionally flexible polymers or other materials to accommodate volume changes during cycling without breaking the support structure or encapsulant.

Typical fabrication strategies for "yoke-shell" nanocomposite structures are described in [Lou et al., Adv. Mater., 2008, 20, 3987-4019. The metal “yoke” material discussed is generally Au, which is not considered to be a useful active material for FIB electrochemical cells. Likewise, the “shell” material described is often SiO ₂ , which is not considered a useful fluoride ion conductive material. Thus, a suitable fabrication strategy for "yoke-shell" nanocomposites useful in FIB electrochemical cells is schematically shown below. These are intended to be exemplary and do not limit the invention. In certain examples, Cu metal or CuF ₂ is used as an example of an active material “yoke” and LaF ₃ is used as an example of an encapsulant or “shell” material; Any material capable of accepting or releasing fluoride ions during an electrochemical reaction can be envisioned to constitute a "yoke" and any phase or material that allows the exchange of F- between the electrolyte and the active material is an encapsulant or shell. Since it can be conceived to constitute, as before, they do not limit the invention. In certain embodiments, the active material is less than 1 micron in diameter, most usefully, the active material “yoke” is between 1 nm and 500 nm in diameter and the encapsulant is from 2 nm to 100 nm in thickness.

) 합성 또는 졸-겔 반응) 하에서 테트라에틸오르쏘실리케이트(tetraethylorthosilicate; TEOS) 또는 나트륨 실리케이트(sodium silicate) 용액(물 유리)과 같은 가수 분해성 실리카 소스의 후속하는 첨가는, SiO₂에 의한 Cu 나노입자의 등각적인 코팅으로 나타난다. SiO₂ 층의 두께(및, 그러므로, 결과적으로 나타나는 공극 공간)는 사용되는 SiO₂ 프리커서의 양 및 반응 조건의 수정에 의해 제어될 수 있다. 그 다음, SiO₂ 코팅된 Cu 나노입자는 (옵션 사항으로 Lutensol(루텐솔) AO와 같은 계면활성제의 존재 하에서) 졸-겔 반응에 의해 LaF₃의 외부 층으로 코팅되는데, 그에 의해 이 코팅의 두께는 사용되는 LaF₃ 프리커서의 양 및 반응 조건에 의해 수정될 수 있다. 이 단계는 중간 Cu@SiO₂ 재료의 분리 및/또는 정제 이후에 행해질 수 있거나, 또는 SiO₂ 층의 형성 이후에 동일한 반응 혼합물에서 수행될 수 있다. 결과적으로 나타나는 Cu@SiO₂@LaF₃ 복합재는, 옵션 사항으로, 어닐링 단계를 겪을 수도 있고, 및/또는 SiO₂ 층은, 그 다음, 적절한 조건 하에서 NaOH 또는 HF와 같은 SiO₂에천트 재료에 대한 복합재의 노출에 의해 제거되어 Cu@LaF₃ "요크 쉘" 조성물을 제공한다. 이 재료는 후속하여, 옵션 사항으로 Cu 표면을 정제하기 위한 H₂와 같은 환원제의 존재 하에서, 최종 어닐링 단계를 겪을 수도 있다.1b schematically shows a typical route using a sacrificial inorganic "intermediate" layer such as SiO ₂ . For example, Cu nanoparticles may contain hydrazine or similar reducing agents in the presence of stabilizing and/or coordination species such as sodium citrate and/or surfactants (e.g., cetyltrimethylammonium bromide). It can be prepared by reduction of a solution of Cu ²⁺ ions using. Aminopropyltrimethoxysilane, APTS, (or other suitable bifunctional species such that one part of the molecule is coordinated to the Cu surface and the other part provides a reactive silicone moiety to the external environment. Exposure of Cu nanoparticles to a surface-modifying ligand such as) and appropriate conditions (e.g., Stauber (

) Under synthesis or sol-gel reaction), the subsequent addition of a hydrolyzable silica source such as tetraethylorthosilicate (TEOS) or sodium silicate solution (water glass), Cu nanoparticles by SiO ₂ Appears as a conformal coating of. The thickness of the SiO ₂ layer (and, therefore, the resulting void space) can be controlled by modification of the reaction conditions and the amount of SiO ₂ precursor used. Then, SiO ₂ coated Cu nanoparticles are coated with an outer layer of LaF ₃ by a sol-gel reaction (optionally in the presence of a surfactant such as Lutensol AO), whereby the thickness of this coating Can be modified by the amount of LaF ₃ precursor used and the reaction conditions. This step can be done after separation and/or purification of the intermediate Cu@SiO ₂ material, or can be carried out in the same reaction mixture after formation of the SiO ₂ layer. The resulting Cu@SiO ₂ @LaF ₃ composite may, optionally, undergo an annealing step, and/or the SiO ₂ layer, then, under appropriate conditions, to a SiO ₂ etchant material such as NaOH or HF. It is removed by exposure of the composite to provide a Cu@LaF ₃ "yoke shell" composition. This material may subsequently undergo a final annealing step, optionally in the presence of a reducing agent such as H ₂ to purify the Cu surface.

1D illustrates a similar route using a sacrificial polymer “intermediate” layer. For example, Cu nanoparticles are, by means of a polymer shell, amino-(amino-), hydroxyl-(hydroxyl-), carboxylate or other ionizable functional groups (such as poly(acrylic acid)). acid)), poly(ethyleneimine)), poly(vinyl alcohol)), poly(styrene sulfonate)), protein, polysaccharide, Or by formation of Cu nanoparticles in the presence of a polymer or copolymer characterized by gelatin), or by growth of a polymer from the surface of appropriately modified Cu nanoparticles (e.g., atom transfer radical polymerization) polymerization) by poly(styrene sulfonate) grown from an 11-aminoundecyl 2-bromoisobutyrate functionalized surface. The thickness of the polymer layer (and the resulting void space) can be controlled by the polymer concentration and/or molecular weight. Sol - it is the shell of the LaF ₃ growing around the outside of the Cu @ polymer nanocomposites by gel reaction, and provides a Cu @ ₃ @LaF polymer nanocomposites. The polymer layer is then removed by decomposition at elevated temperatures (in air or under an inert gas such as Ar) or dissolution in a suitable solvent (e.g., toluene, dichloromethane or acetone) to the desired Cu@LaF ₃ "yoke-shell" composition is provided. This material may subsequently undergo a final annealing step, optionally in the presence of a reducing agent such as H ₂ to purify the Cu surface. Alternatively, [McDonald and Devon, Adv. Colloid. Interf. Sci., 2002, 99, 181-213], a polymer core-shell architecture such as hollow latex-type particles may be used as a template. In this case, Cu nanoparticles are (preformed hollow latex By either exposure of Cu nanoparticles to the particles or coordination of Cu ions in solution to an ionizable prepolymer or copolymer, subsequent reduction of Cu ions to provide Cu nanoparticles, and then, for example, For example, it is captured) by the creation of a hollow structure through solvent removal, and if necessary, growth of the LaF ₃ shell, removal of the polymer and annealing are followed, resulting in a Cu@LaF ₃ "yoke-shell" composition.

Figure 1d shows an alternative route without the sacrificial "intermediate" layer. For example, Cu nanoparticles are Cu@LaF ₃ "core-shell" composites where the outer layer of LaF ₃ is grown by a sol-gel reaction-which may then, optionally, undergo an annealing step subsequently- Prior to providing, it is treated with a suitable surface-modifying ligand (eg 11-aminoundecanoic acid, AUDA). Appropriate etchants (e.g. KCN, HCl/H ₂ O ₂ or FeCl ₃ ; for a wide variety of metals and compounds, which are made possible by controlling the reaction conditions (e.g., etchant concentration, temperature, reaction time)) Appropriate etchants for Cu are given in ["The CRC Handbook of Metal Etchants" (CRC, 1990, P. Walker and WH Tarn eds.), and may be chosen so as not to affect the "shell" material). Partial etching of the “core” creates void spaces in the Cu@LaF ₃ particles, giving a “Yoke-shell” Cu@LaF ₃ composition. This material may subsequently undergo a final annealing step, optionally in the presence of a reducing agent such as H ₂ to purify the Cu surface.

1E depicts a change to the above-described "sacrificial" composition in which nanoparticles of an active material are grown on the surface of a "sacrificial" material (where it is the innermost material to be removed). For example, one or more Cu nanoparticles are grown on the surface of amino-functionalized poly(styrene) or SiO ₂ particles. The resulting composite material is treated with an appropriate Cu surface modification ligand (eg AUDA), after which the outer layer of LaF ₃ is grown by a sol-gel reaction. The innermost material is removed by pyrolysis, etching or dissolution, resulting in a "yoke-shell" Cu@LaF ₃ composition characterized by one or more Cu nanoparticles. This material may subsequently undergo a final annealing step, optionally in the presence of a reducing agent such as H ₂ to purify the Cu surface(s) and, optionally, to aggregate the Cu nanoparticles.

1F schematically depicts an alternative strategy in which the active material is grown in pores or internal structures of preformed “sacrificial” material. For example, Cu nanoparticles may be grown inside hollow SiO ₂ nanospheres (for possible synthetic approaches, see [Hah et al., Chem. Commun., 2004, 1012-1013]). Then, these Cu@SiO ₂ "core-shell" nanocomposites are coated with an outer layer of LaF ₃ by a sol-gel reaction (optionally in the presence of a surfactant such as Lutensol AO), thereby The thickness can be modified by the amount of LaF ₃ precursor used and the reaction conditions. The resulting Cu@SiO ₂ @LaF ₃ composite may, optionally, undergo an annealing step, and/or the SiO ₂ layer, then, under appropriate conditions, to a SiO ₂ etchant material such as NaOH or HF. It is removed by exposure of the composite to provide a Cu@LaF ₃ "yoke shell" composition. This material may subsequently undergo a final annealing step, optionally in the presence of a reducing agent such as H ₂ to purify the Cu surface. In a related synthesis, micro or mesoporous materials, such as zeolites, may be used as "templates" for Cu nanoparticle formation, followed by the subsequent Cu@LaF ₃ "yoke-shell" generation of a similar pattern.

Figure 1G also shows that a highly-electropositive metal or its metal fluoride such as CaF ₂ is a poly(styrene)-poly(acrylic acid) latex copolymer in a suitable solvent. ) depicts a similar alternative strategy for growing within the interior space of hollow materials such as latex copolymer). These polymeric encapsulated CaF ₂ nanocrystals are then formed into an outer layer of fluoride ion conducting material with adequate electrochemical stability so that it does not decrease itself at the conversion potential of CaF ₂ to Ca (~0.2 V versus Li+/Li). Is coated with. An example of a suitable protective material is a solid solution such as Ca _x Ba _y F ₂ (x + y = 1) in which the Ca ²⁺ and Ba ²⁺ ions in the protective shell are not substantially reduced during the conversion reaction of the CaF ₂ particles in the shell. Including; In contrast, the shell itself, characterized by an electrically less positive metal element (eg LaF ₃ ), will be preferentially reduced over the inner CaF ₂ particles. The resulting CaF ₂ @polymer@Ca _x Ba _y F ₂ composite may, optionally, be subjected to an annealing step, and/or, then, the polymer layer, a suitable solvent etchant material or high temperature to remove the polymer. It is removed by exposure of the composite to the CaF ₂ @Ca _x Ba _y F ₂ "yoke-shell" composition.

Encapsulation described, along with electrolytes, binders, additives, separators, battery casings or packaging, current collectors, electrical contacts, electronic charge and discharge controllers, and other elements of battery construction known to those skilled in the art. Using active material and/or yoke-shell nanocomposite electrodes, it is possible to create useful lithium-free electrochemical cells operable at temperatures ranging from -40 degrees Celsius to 200 degrees Celsius. Such electrochemical cells may have substantially irreversible electrochemical reactions during discharge, making them suitable for forming galvanic cells or primary batteries. Alternatively, certain structures and compositions having an electrochemical reaction are at least partially reversible through the application of an electric charge, and secondary (rechargeable) batteries can be formed.

In certain embodiments, an electrolyte suitable for the FIB battery system may include a fluoride salt and a solvent in which the fluoride salt is at least partially dissolved. The fluoride salt can be a metal fluoride or a non-metal fluoride. The solvent may be an organic liquid or an ionic liquid, or a mixture of both. In another embodiment, an electrolyte suitable for a FIB battery system may include a composite electrolyte containing a fluoride salt, a polymer, and, optionally, an organic liquid, an ionic liquid, or a mixture of the two. Electrolytes may include, but are not limited to, combinations of fluoride salts and solvents disclosed in U.S. Patent No. 9,166,249 entitled "Fluoride Ion Battery Compositions," the disclosure of which is incorporated herein by reference. Does not.

For example, liquid electrolyte salts suitable for FIB systems may contain complex cations that combine with fluoride anions. The cation may be characterized by an organic group such as an alkylammonium, alkylphosphonium or alkylsulfonium species, or a metal organic such as metallocenium species. Or it may be composed of a metal coordination complex motif. Solvents useful for such liquid electrolyte salts include non-aqueous solvents (referred herein as "organic") capable of dissolving the above-mentioned fluoride salts in a molar concentration of 0.01 M or more, preferably between 0.1 and 3 M. It can also be included. Examples of such solvents include acetone, acetonitrile, benzonitrile, 4-fluorobenzonitrile, pentafluorobenzonitrile, triethylamine (TEA), diisopropylethylamine, 1,2-dimethoxyethane, Ethylene carbonate, propylene carbonate (PC), γ-butyrolactone, dimethyl carbonate, diethyl carbonate (DEC), methyl ethyl carbonate, propyl methyl carbonate, tetrahydrofuran, 2-methyltetrahydrofuran, Nitromethane, benzene, toluene, chloroform, dichloromethane, 1,2-dichloroethane, dimethylsulfoxide, sulfolane, N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA) ), carbon disulfide, ethyl acetate, methyl butyrate, n-propyl acetate, methyl propionate, methyl formate, 4-methyl-1,3,-dioxolane, pyridine, methyl isobutyl ketone, methyl ethyl ketone, hexamethyl Phosphoramide, hexamethylphosphorus triamide, 1methyl-2-pyrrolidinone, 2-methoxyethyl acetate, trimethyl borate, triethylborate and substituted derivatives thereof, as well as ethylmethylsulfone, trimethylenesulfone, 1 -Methyltrimethylene sulfone, ethyl-sec-butyl sulfone, ethyl isopropyl sulfone (EIPS), 3,3,3-trifluoropropylmethyl sulfone, 2,2,2-trifluoroethyl sulfone, Bis(2,2,2-trifluoroethyl)ether (BTFE), glyme (e.g., diglyme, tetraglyme), 1, 2-dimethoxyethane (DME) and mixtures thereof. In certain embodiments, an ionic liquid material at room temperature, or an ionic liquid that holds the liquid at a temperature of less than 200 degrees Celsius (eg, ["Electrochemical Aspects of Ionic Liquids", E. Ohno ed., Wiley Interscience, New) York, 2005] is preferred. These are 1-methyl,1-propylpiperidinium bis(trifluoromethanesulfonyl)imide; MPPTFSI), butyltrimethylammonium bis(trifluoromethanesulfonyl)imide. )Imide (butyltrimethylammonium bis(trifluoromethanesulfonyl)imide; BTMATFSI) and 1-butyl,1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide; BMPTFSI ) And their fluoroalkylphosphate (FAP) anionic derivatives (e.g. MPPFAP), where FAP is a hydrophobic anion such as tris(pentafluoroethyl)trifluorophosphate). Ionic liquids that remain liquid in, all of which alone or in combination are useful solvents.

In certain other embodiments, an electrolyte suitable for the FIB battery system comprises a composition disclosed above with the addition of a fluoride ion complexing species such as an anion acceptor, a cation complexing species such as a crown ether, or a combination of both. Can include. Suitable anion acceptors include fluoride anions such as boron, aluminum, ammonium, H-bond donors or similar groups, such as McBreen et al., J. Power Sources, 2000, 89, 163 and West et al., J. Electrochem. Soc., 154, A929 (2007)] and species capable of binding aza ethers and alkyl and aryl boron and borate complexes, and [Nair et al., J. Phys. Chem. A, 113, 5918 (2009)], both of which are incorporated herein by reference. In particular, tris (hexafluoroisopropyl) borate, tris (pentafluorophenyl) borane and difluorophenyl boroxin (DFB), trifluorophenyl boroxin, bis (trifluoromethyl) phenyl boroxin , Trifluoromethyl)phenyl boroxine and all possible regioisomers of fluoro(trifluoromethyl)phenyl boroxine may be used.

As will be appreciated, a fluoride ion battery is a vehicle traction battery (electric vehicle (EV), hybrid vehicle (HEV), and plug-in hybrid (PHEV)) or vehicle starter or ignition battery. It is suitable for a wide range of primary or rechargeable applications, including but not limited to. FIB systems include emergency power, local energy storage, starters or ignitions, remote relay stations, communication base stations, uninterruptible power supplies (UPS), spinning reserves, peak shaving, or load leveling, or It may be a stationary battery useful for other electrical grid electricity storage or optimization applications. Like other portable applications such as flashlights, toys, power tools, portable radios and televisions, mobile phones, camcorders, laptops, tablets or handheld computers, portable instruments, cordless devices, wireless peripherals, or emergency beacons, watch batteries, Small format or small battery applications are contemplated including implanted medical device batteries, or sensing and monitoring system batteries (including gas or electricity meters). Applications in military or extreme environments are also possible, including use in satellites, ammunition, robots, unmanned aerial vehicles or for military emergency power or communications.

III(c) Comparative Example 1 and Experimental Example 1

In Comparative Example 1, copper nanoparticles were prepared and analyzed without a shell. First, 2 mmol of Cu(NO ₃ )2·2.5H ₂ O and 1.87 mmol CTAB were dissolved in 75 ml water at room temperature, and 0.5 ml NH ₄ OH (28 to 30 wt% NH _{3 in water} , 14.8M) was added. The pH was adjusted to about 10-11. A solution containing hydrazine (50-60% reagent grade 3 ml), CTAB (1.87 mmol), and citric acid (0.38 mmol) in water (75 ml) under argon was prepared, and a solution of copper nitrate was added. Mix for about 20 minutes before following. To maximize copper nanoparticle growth, the reaction mixture was stirred for 1.5 hours. The resulting copper nanoparticles (~ 50 nm) were separated and washed. Specifically, the reaction synthesis mixture was centrifuged, decanted, mixed with ethanol and sonicated. 3 shows an X-ray diffraction (XRD) spectrum of copper nanoparticles during preparation. Three peaks are visible, all corresponding to Cu (°2θ): 43.0, 50.5, and 74.0. However, upon exposure to air, Cu is oxidized to Cu ₂ O, which starts to form at least 4 days early and is the main product after 9 days. This is illustrated in Fig. 4 showing the appearance of the new peaks at 29.5, 42.3, 61.3 and 73.5 (°2θ), corresponding to Cu ₂ O.

In Experimental Example 1, core-shell nanoparticles including a core including copper nanoparticles coated with a shell containing lanthanum fluoride (Cu/LaF ₃ ) were prepared according to the present disclosure. ~50 nm copper nanoparticles were prepared using the same method as in Comparative Example 1, but with 3 ml of hydrazine (3 ml of 50-60% reagent grade) under an argon atmosphere following separation and washing of the copper nanoparticles. Redispersed in water. For a mixture of water, copper nanoparticles, and hydrazine, a solution of La(NO ₃ ) ₃ ·6H ₂ O (1 mmol in 15 ml H ₂ O) and a solution of NaF (1 mmol in 15 ml H ₂ O) is added. Became. The reaction mixture was stirred for 10 minutes and then centrifuged.

The precipitate was separated by centrifuge and analyzed by XRD. The XRD spectrum of the core-shell nanoparticles during synthesis is shown in FIG. 5. The XRD spectrum shows five peaks (°2θ): 25.0 (LaF ₃ ), 28.0 (LaF ₃ ), 43.5 (Cu), 50.4 (Cu), and 74.0 (Cu). 6 shows stacked XRD spectra of core-shell nanoparticles upon exposure to air for 9, 16, and 23 days. In contrast to Comparative Example 1, no spectral change was observed. 7A and 7B show TEM images of core-shell nanoparticles during synthesis. As shown, the copper nanoparticle core is covered with a LaF ₃ shell. The shell is about 0.30 nanometers thick. 8A to 8C show high-resolution TEM images of core-shell nanoparticles during synthesis. The black area in the center corresponds to the copper core, and the black and white areas around it correspond to the LaF ₃ shell. The figure shows a uniform coating of a copper core coated directly with a LaF ₃ shell.

Therefore, the core-shell nanoparticles synthesized in Experimental Example 1 provide a shell capable of protecting the underlying metal core. Such core-shell nanoparticles are useful for applications where operating conditions dissolve, oxidize, or otherwise contaminate the metal core. Illustrative examples include the use of core-shell nanoparticles as battery electrode materials.

In a non-limiting example as shown in FIG. 9, the core-shell nanoparticles of Experimental Example 1 may be included as an active material in the negative electrode (anode) of the F-shuttle battery. The LaF ₃ shell protects the copper core, allowing the copper core to not dissolve and act as an active material. As shown in FIGS. 10A and 10B, the core-shell nanoparticles of Experimental Example 1 were tested as an active material in the anode. The anode contained core-shell nanoparticles, a conductive agent (super P carbon), and a PVdF binder in a ratio of 8:1:1.

Comparative Example 2

Attempts have been made to prepare core-shell nanoparticles comprising a core comprising copper nanoparticles coated directly with a shell comprising lanthanum fluoride (Cu/LaF ₃ ). Comparative Example 2 was performed in the same manner as in Experimental Example 1, except that 1 mmol of LaCl ₃ 7H ₂ O was used instead of La(NO ₃ ) ₃ ·6H ₂ O.

The XRD spectrum of the nanoparticles synthesized in Comparative Example 2 is shown in FIG. 11. The XRD spectrum shows five peaks (°2θ): 24.5 (LaF ₃ ), 27.6 (LaF ₃ ), 43.6 (Cu), 50.5 (Cu), and 74.1 (Cu). Thus, Cu remains during the course of the reaction of LaCl ₃ and NaF.

However, the oxidation of Cu following exposure of the core-shell nanoparticles of Comparative Example 2 indicated that the shell was not formed correctly. 12 shows stacked XRD spectra of nanoparticles synthesized in Comparative Example 2 upon exposure to air for 8 days, 15 days, and 22 days. Additional peaks starting at day 8 (°2θ) are observed: 35.4, 36.4, 38.8, 42.5, 44.8, 48.7, 52.3, 61.5, 73.5. Peaks at at least 36.4, 42.5, 61.5, and 73.5 degrees (°2θ) are consistent with Cu ₂ O formation. The peaks at 43.6, 50.5 and 74.1 degrees (°2θ) consistent with Cu also decreased in intensity. As shown in Fig. 13, the TEM image shows a non-uniform partial coating of Cu nanoparticles by LaF ₃ , as well as LaF ₃ not related to the Cu nanoparticles. Thus, a shell made of LaCl ₃ ·7H ₂ O does not appear to be a preferred core-shell composition because it will leave the Cu core exposed to the environment of an electrochemical cell that may dissolve the Cu core. In addition, LaF ₃ , which is not associated with Cu nanoparticles, will reduce the overall efficiency of any system incorporating the mixture.

Study of stacked thin film electrodes

Core and shell materials can also be studied in thin film electrode configurations. Briefly, copper was sputtered to a thickness of about 80 nm onto a 1 mm thick glassy carbon substrate. After the formation of the Cu film, LaF ₃ was sputtered onto the Cu layer to a thickness of less than 5 nm, forming a double layer thin film; For comparison purposes, a single layer of Cu thin film without a LaF ₃ coating was also prepared. Ag wire immersed in 1-methyl-1-propylpyrrolidinium bis(trifluoromethylsulfonyl)imide (MPPyTFSI) and 0.01 M AgOTf as a reference electrode, and A thin film was studied in a three-electrode cell configuration using a Pt wire as a counter electrode and 0.1M tetramethylammonium fluoride (TMAF) in MPPyTFSI as an electrolyte. In contrast to Ag/Ag ⁺ , cyclic voltage current was measured in the range from -2.4 V to -0.7 V. The evaluation was performed in a glove box free of moisture and oxygen.

The obtained cyclic voltammetry curve is shown in FIG. 14. In the case of a bilayer thin film, the measured anode peak was symmetrical with the cathode peak, and no copper ions were detected in the electrolyte by ICP-MS. These results later indicate the reversible transport of fluoride ions from the LaF ₃ layer to Cu. In contrast, the cyclic voltammetry curve obtained for a single layer of Cu thin film is asymmetric. The anode current exceeds the cathode current, indicating the dissolution of Cu during the anode reaction. The ICP-MS data confirm this, indicating 5 ppm Cu in the electrolyte.

The Cu-LaF ₃ bilayer thin film electrode was also studied by XPS initially and after fluorination at the voltage shown in Fig. 15A. The initial time point (1 in Figure 15A) was studied at the time of deposition. The potential was then swept from OCV (about -1.5 V versus Ag/Ag ⁺ ) to -0.8 V and held for 1 hour. After the fluorination reaction, samples of the electrodes were taken for XPS depth profiling analysis.

In the initial XPS spectrum (Fig. 15B), the surface contains more La and F than Cu. After fluorination, fluoride ions can be detected at higher levels at deeper depths than in the initial XPS spectrum; In the initial spectrum, fluoride levels fell more rapidly with increasing depth. Overall, XPS data indicate that fluoride ions can penetrate into the copper layer. Thus, after reduction, fluoride ions can diffuse into the Cu core.

Example 3

Core-shell nanoparticles with shells of the formula Cu@Ba _x La _1-x F _3-x are schematically shown in FIG. 16; Cu@LaF ₃ is included for comparison. Initially, the copper nanoparticle core may be up to about 50 nm in diameter and the LaF ₃ or Ba _x La _1-x F _3-x coating may be about 5 nm thick. The CuF ₂ layer formed on the Cu core during battery charging can be grown to a thickness of about 3 nm in Cu@LaF ₃ nanoparticles. However, by doping Ba with the LaF ₃ shell, the CuF ₂ layer can be grown to a larger thickness.

The ionic conductivity of LaF ₃ is quite low, especially at room temperature. It is only about 10 ^-8.5 S/Cm, and limits the F anion migration. However, inclusion of Ba dopants in the LaF ₃ shell (ie, making Cu@Ba _x La _1-x F _3-x ) increases the conductivity of the shell. It has been reported that the conductivity of LaF ₃ increases by a factor of 100 upon Ba doping; For example, [M. Anji Reddy and M. Fichtner, Batteries based on fluoride shuttle, J. Mater. Chem. 2011, 21, 17059-17062]. The high ionic conductivity is advantageous for the production of CuF ₂ during charging and appears as a capacity improvement.

SEM, TEM, and EDX images of exemplary Cu@Ba _x La _1-x F _3-x nanoparticles are included in FIGS. 17A-17H. XPS can be used to determine the composition of each element. 18A-18D show representative XPS spectral data for core@shell nanoparticles containing Cu (64.83%), La (14.68%), Ba (0.28%), and F (20.21%), where It itself confirms that the nanoparticles are Cu@La _0.97 Ba _0.03 F _2.97 , including La (41.75 %), Ba (0.79 %) and F (57.46 %). The XRD spectra of Cu@LaF ₃ and Cu@La _0.97 Ba _0.03 F _2.97 are shown in FIG. 19.

20A and 20B illustrate the capacity improvement achieved upon Ba doping in accordance with some aspects of the present disclosure. 20A shows the voltage profile of the initial charge-discharge cycle of a Cu@LaF ₃ electrode or a Cu@Ba _x La _1-x F _3-x electrode compared to an Ag/Ag ⁺ reference electrode. The capacity transfer of the Ba-doped electrode reaches 95.2 mAh/g, compared to only 50.2 mAh/g for Cu@LaF ₃ (FIG. 20B ). Thus, the Ba doping of the LaF ₃ shell almost doubles its capacity. Through Ba doping, the ionic conduction of the LaF ₃ shell is improved by about 100 times; For example, [M. Anji Reddy and M. Fichtner, Batteries based on fluoride shuttle, J. Mater. Chem. 2011, 21, 17059-17062]. Fluoride ions can easily migrate through the shell and react with Cu to form CuF ₂ , and the amount of CuF ₂ formation directly determines the capacity of the battery. The more CuF ₂ formed, the greater the capacity of the battery. Therefore, by Ba doping of the LaF ₃ shell, the utilization of Cu can be almost doubled.

In addition, FIGS. 20C and 20D show the XRD of Cu@La _0.97 Ba _0.03 F _2.97 and Cu@LaF ₃ in the initial state, that is, in the electrode before first use, then after the initial charge and subsequent initial discharge. Spectra are shown respectively. CuF ₂ is formed after the initial charge, and then can be reduced to Cu after the initial discharge. 20C and 20D show that Cu can be circulated in a liquid electrolyte using two types of shells.

Because Cu is inexpensive, light metal, and has a high capacity (843.5 mAh/g theoretical capacity), Cu is a good cathode material for fluoride shuttle batteries. However, the main challenge for its use is that Cu cannot be charged to form CuF ₂ in the liquid electrolyte/cell due to Cu dissolution. In the case of Cu@LaF ₃ , the LaF ₃ shell effectively prevents Cu from dissolution during charging/discharging. As a result, Cu CuF ₂ is may be charged to CuF ₂ during filling, while discharge can be reduced to Cu. However, its capacity is low due to the low ionic conductivity of LaF ₃ . Through a Ba doped shell (eg La _0.97 Ba _0.03 F _2.97 ), the ionic conductivity of the shell can be improved 100 times, that is, the shell has a low resistance. The F ions easily pass through the shell so that more Cu can be fluorinated with CuF ₂ during charging. Compared to the undoped LaF ₃ shell, the capacity is doubled. With a Ba doped shell, CuF ₂ can be detected after filling. After discharge, CuF ₂ is reduced to Cu. It can be seen that in liquid cells, Cu is rechargeable and that Cu utilization can be improved using a Ba-doped shell.

While the aspects described herein have been described in connection with the exemplary aspects outlined above, various alternatives, modifications, alterations, improvements, and/or known or currently unpredictable or unpredictable. Alternatively, a practical equivalent example may be made clear to a person having at least ordinary knowledge in the technical field. Accordingly, the exemplary aspects as described above are intended to be illustrative, not restrictive. Various changes may be made without departing from the spirit and scope of the present disclosure. Therefore, this disclosure is intended to cover all known or later developed alternatives, modifications, variations, improvements, and/or substantial equivalents.

Accordingly, the claims are not intended to be limited to the aspects shown herein, but are intended to be accorded the full scope consistent with the language of the claims, wherein reference to the singular element is, unless specifically so stated, It is not intended to mean “one and only one”, but rather is intended to mean “one or more”. All structural and functional equivalents to elements of the various aspects described throughout the present disclosure known to those of ordinary skill in the art or to be known later, are expressly incorporated herein by reference and incorporated in the claims. It is intended to be covered by. Moreover, nothing disclosed herein is intended to be dedicated to the public, regardless of whether such disclosure is explicitly recited in the claims. No element of a claim is to be construed as a means plus function unless that element is explicitly stated using the phrase “means for doing”.

In addition, the word “example” is used herein to mean “serving as an example, illustration, or illustration”. Any aspect described herein as an “example” should not necessarily be interpreted as being preferred or advantageous over other aspects. Unless specifically stated otherwise, the term “some” refers to one or more. Combinations such as “at least one of A, B, or C”, “at least one of A, B, and C”, and “A, B, C, or any combination thereof” include A, B, and/ Or any combination of C, and may include multiple A, multiple B, or multiple C. Specifically, combinations such as “at least one of A, B, or C”, “at least one of A, B, and C”, and “A, B, C, or any combination thereof” are A alone, B alone, C alone, A and B, A and C, B and C, or A and B and C may also be, wherein any such combination may include one or more members or members of A, B, or C. May be. Nothing disclosed herein is intended to be dedicated to the public, regardless of whether such disclosure is explicitly recited in the claims.

Examples are presented to provide a complete disclosure and description of how to make and use the present invention to those skilled in the art, and are not intended to limit the scope of what the inventors conceive as their invention. It is also not intended to indicate that the experiment of is all or the only experiments performed. Efforts have been made to ensure accuracy with respect to the numbers used (eg, quantities, dimensions, etc.), but some experimental errors and deviations must be considered.

In addition, all references throughout this application, such as patent documents, including issued or issued patents or equivalents; Publication of patent applications; Non-patent literature documents or other source material; As if individually incorporated by reference, they are incorporated in their entirety by reference herein.

Claims (25)

As an electrochemically active structure,
A core comprising an active material, and
A fluoride-containing shell at least partially surrounding the active material
Including,
The fluoride-containing shell includes a first metal and a second metal, and the first metal is barium. An electrochemically active structure. The method of claim 1,
The active material contains metal nanoparticles selected from iron nanoparticles, cobalt nanoparticles, nickel nanoparticles, copper nanoparticles, lead nanoparticles, and alkaline earth metal nanoparticles, which are electrochemically active. Structure. The method of claim 1,
The active material will contain copper nanoparticles, electrochemically active structure. The method of claim 1,
Wherein the fluoride-containing shell is directly attached to the core. The method of claim 1,
The fluoride-containing shell is spaced apart from the core to define a void space therebetween. The method of claim 1,
The second metal is lanthanum (lanthanum), the electrochemically active structure. The method of claim 6,
The barium and the lanthanum are present in a ratio of x to 1-x, and as a result, the sum of the moles of barium and the moles of lanthanum in the empirical formula of the fluoride-containing shell is 1, which is electrochemically active. Structure. The method of claim 7,
x is between about 0.03 and about 0.15, the electrochemically active structure. The method of claim 8,
wherein x is about 0.03. As a method of preparing coated metal nanoparticles,
a) providing a water/metal nanoparticle mixture;
b) exposing the water/metal nanoparticle mixture to an inert atmosphere; And
c) forming a fluoride-containing shell around the metal nanoparticle core
Including,
The fluoride-containing shell includes a first metal and a second metal, and the first metal is barium. The method of producing a coated metal nanoparticle. The method of claim 10,
The metal nanoparticles are iron nanoparticles, cobalt nanoparticles, nickel nanoparticles, copper nanoparticles, lead nanoparticles, or alkaline earth metal nanoparticles. The method of producing a coated metal nanoparticle. The method of claim 10,
The method of manufacturing a coated metal nanoparticle, wherein the metal nanoparticles include copper nanoparticles. The method of claim 10,
The fluoride-containing shell is attached directly to the core, the method of producing a coated metal nanoparticle. The method of claim 10,
The fluoride-containing shell is spaced apart from the core so as to define a void space between the core and the core. The method of claim 10,
The second metal is lanthanum, the method of producing a coated metal nanoparticles. The method of claim 15,
The barium and the lanthanum are present in a ratio of x to 1-x, and as a result, the sum of the moles of barium and the moles of lanthanum in the empirical formula of the fluoride-containing shell is 1, to prepare a coated metal nanoparticle. Way. The method of claim 16,
x is about 0.03 to about 0.15, wherein the method of producing a coated metal nanoparticle. The method of claim 10,
The step of forming the fluoride-containing shell comprises adding a first metal salt, a second metal salt, and a fluoride-containing salt to the water/metal nanoparticle mixture to create a fluoride-containing shell around the metal nanoparticle core. Including, wherein the first metal salt is a barium salt, a method of producing a coated metal nanoparticle. The method of claim 18,
The second metal salt is a lanthanum salt, the method of producing a coated metal nanoparticles. The method of claim 19,
The first metal salt is barium nitrate, and the second metal salt is lanthanum nitrate. The method of producing a coated metal nanoparticle. The method of claim 20,
The barium nitrate and the lanthanum nitrate are used in a molar ratio of about 1:10, the method of producing a coated metal nanoparticle. As an electrode,
A core comprising copper nanoparticles, and
A fluoride-containing shell at least partially surrounding the copper nanoparticles,
The fluoride-containing shell contains barium and lanthanum in a ratio of x to 1-x, and as a result, the sum of the moles of barium and the moles of lanthanum in the empirical formula of the fluoride-containing shell is 1. The method of claim 22,
x is about 0.03 to about 0.15. A fluoride shuttle battery comprising the electrode of claim 22 and a liquid electrolyte. As an electrochemically active structure,
A core containing an active material, and
A fluoride-containing shell at least partially surrounding the active material
Including,
The fluoride-containing shell includes a first metal and a second metal, and the first metal is a divalent or tetravalent metal cation. An electrochemically active structure.

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