Electrolyte formulations and additives for iron anode electrochemical systems

Abstract

Systems, methods, and apparatus of various aspects include the use of tin, antimony, and / or indium as an additive to an electrolyte and / or an electrode in an electrochemical system having an iron-based anode, such as a battery. In some aspects, the addition of tin, antimony, and / or indium may improve cycling of the iron-based anode. Systems, methods, and apparatus of various aspects include the use of high hydroxide concentration electrolytes in electrochemical systems, such as batteries. In some aspects, the high hydroxide concentration electrolyte may increase the amount of charge stored in the cell (i.e., the capacity of the battery pack material) and / or reduce the overpotential of the battery (i.e., increase the voltage).

Description

[0001] Related Applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 17 / 661,256, filed on April 28, 2022, entitled “Electrolyte Formulations and Additives for Iron Anode Electrochemical Systems,” the entire contents of which are incorporated herein by reference for all purposes. Background Art

[0003] Energy storage technologies play an increasingly important role in the electric grid; at the most basic level, these storage assets provide smoothing to better match generation and demand on the grid. The services performed by energy storage devices benefit the grid at multiple time scales (from milliseconds to years). Today, energy storage technologies exist that can support time scales from milliseconds to hours, but long-duration and ultra-long-duration (in general, >8 hours) energy storage systems are needed.

[0004] Iron-based negative electrode electrochemical systems (or alternatively, iron-based anode electrochemical systems) are attractive options for electrochemical energy storage. However, iron-based negative electrodes may have difficulty achieving high performance, especially at lower discharge rates, such as discharge rates associated with full discharge times greater than about 8 hours (e.g., 8 hours, greater than 8 hours, 8-16 hours, 16 hours, greater than 16 hours, 16-24 hours, 24 hours, greater than 24 hours, 24-30 hours, 30 hours, greater than 30 hours, etc.). Direct reduced iron ("DRI") is an excellent candidate for iron-based negative electrodes due to its cost, but despite the promising material properties of DRI, electrodes made from DRI may face challenges in achieving performance improvements.

[0005] Iron-based alkaline electrochemical systems are attractive options for grid-scale, long-duration energy storage due to the low equity cost of iron and alkaline electrolyte components. However, iron-based materials have some disadvantages in alkaline electrolytes, especially competition with the hydrogen evolution reaction and self-discharge. In addition, grid-scale energy storage requires the use of raw materials that are lower in cost and therefore lower in purity than conventional iron electrode materials. Therefore, it may be difficult to circulate iron electrode materials, especially the metallic iron-iron hydroxide reaction (step 1 reaction). In most iron electrode systems, this step 1 reaction is critical to achieving high round-trip efficiencies of the battery pack.

[0006] Therefore, there is a need to improve the design and composition of electrochemical systems with iron-based materials, such as iron-based anodes, to enhance the performance of such systems.

[0007] This background section is intended to introduce various aspects of the art that may be relevant to embodiments of the present invention. Therefore, the foregoing discussion in this section provides a framework for a better understanding of the present invention and should not be regarded as an admission of prior art. Summary of the invention

[0008] A plurality of systems, methods and apparatuses include using tin, antimony and / or indium as additives to electrolytes and / or electrodes in electrochemical systems such as batteries having iron-based anodes. In some aspects, the addition of tin, antimony and / or indium can improve the cycling of the iron-based anodes.

[0009] Embodiments may include a battery comprising: a first electrode comprising direct reduced iron (DRI) or another sponge iron powder; an electrolyte; and a second electrode, wherein the first electrode or the electrolyte comprises an additive containing an element having low hydrogen evolution reaction (HER) activity and / or improving the characteristics of the battery. In some embodiments, the element comprises tin, antimony, and / or indium. In various embodiments, improving the characteristics of the battery may include one or more of: improving the charging of the first electrode; improving the conditioning process of the first electrode; improving the reversibility of the half-cell reaction of the first electrode; and improving the discharge capacity of the first electrode.

[0010] Systems, methods, and apparatus of various aspects include using high hydroxide concentration electrolytes in electrochemical systems such as batteries. In some aspects, the high hydroxide concentration electrolyte can increase the amount of charge storage stored in the battery (i.e., the capacity of the battery material) and / or reduce the overpotential of the battery (i.e., increase the voltage).

[0011] Embodiments may include a battery comprising: a first electrode comprising direct reduced iron (DRI) or another sponge iron powder; an electrolyte comprising a hydroxide; and a second electrode, wherein the electrolyte further comprises an additive comprising at least one of tin, lead, or antimony. In some embodiments, the total hydroxide concentration in the electrolyte may be about 6M or greater.

[0012] Various embodiments may include alkyl polyglucosides used as co-additives for metal HER inhibitors. Various embodiments may include incorporating tin into current collectors. Various embodiments may include incorporating tin into sponge iron. Various embodiments may include hydrogen oxidation catalysts and / or hydrogen getters as additives for electrochemical cell anodes. Various embodiments may include lignin sulfonates used as electrolyte additives and / or anion selective membranes. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying drawings, which are incorporated herein and constitute a part of this specification, illustrate exemplary embodiments of the claims and, together with the general description given above and the detailed description given below, serve to explain features of the claims.

[0014] Figure 1 is a schematic diagram of an electrochemical cell according to various embodiments of the present disclosure.

[0015] Figure 2A-2C It is the Pourbaix diagram of tin.

[0016] Figure 3 It is the Pulbaitu of antimony.

[0017] Figure 4 Graphs showing experimental results for different DRI types using different hydroxide concentrations according to various embodiments.

[0018] Figure 5 It is a graph of the solubility of KOH versus temperature.

[0019] Figure 6 This is the phase diagram of K2Sn(OH)6-KOH-H2O system at 25.0℃.

[0020] Figure 7 Aspects of an electrochemical cell including a lignosulfonate membrane according to various embodiments are shown.

[0021] Figure 8-16 Several example systems are shown in which one or more aspects of various embodiments may be used as part of a bulk energy storage system. DETAILED DESCRIPTION

[0022] A number of embodiments will be described in detail with reference to the accompanying drawings. Where possible, the same reference numerals will be used throughout the drawings to refer to the same or similar parts. Reference to specific examples and implementations is for illustrative purposes and is not intended to limit the scope of the claims. The following description of the embodiments of the present invention is not intended to limit the present invention to these embodiments, but is intended to enable those skilled in the art to make and use the present invention. Unless otherwise indicated, the drawings are not drawn to scale.

[0023] As used herein, room temperature is 25° C. unless otherwise specified. Also, standard temperature and pressure are 25° C. and 1 atmosphere. Unless otherwise expressly stated, all tests, test results, physical properties and values ​​related to temperature, pressure, or both are provided at standard ambient temperature and pressure.

[0024] In general, unless otherwise indicated, the term "about" and the symbol "~" as used herein are intended to encompass a variance or range of ±10%, the experimental or instrument error associated with obtaining the stated value, and preferably the greater of these.

[0025] As used herein, ranges of values ​​used herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein. Unless otherwise indicated herein, each separate value within a range is incorporated into the specification as if it were individually recited herein.

[0026] As used herein, unless otherwise indicated, the terms %, weight % (abbreviated as weight %) and mass % are used interchangeably and refer to the weight of the first component as a percentage of the total weight of, for example, a formulation, mixture, particle, pellet, agglomerate, material, structure or product. As used herein, unless otherwise indicated, "volume %" and "% volume" and similar such terms refer to the volume of the first component as a percentage of the total volume of, for example, a formulation, mixture, particle, pellet, agglomerate, material, structure or product.

[0027] As used herein, unless otherwise indicated, the term "mole" (abbreviated "M") is used to refer to molar concentration, also known as molarity, which is defined as the number of moles of a substance per liter (mol / L) in a solution. As an example, a substance having a concentration of 1 mol / L in a solution is referred to herein as 1 M or having a concentration of 1 M. Similarly, millimole (mM) is used herein to mean one thousandth of a mole per liter.

[0028] It should be noted that it is not necessary to provide or address the theoretical basis for the novel and groundbreaking methods, materials, performances, or other beneficial features and characteristics that are the subject of or related to the embodiments of the present invention. However, a variety of theories are provided in this specification to further advance the technology in this field. Unless otherwise expressly stated, the theories proposed in this specification in no way limit, restrict, or narrow the scope of protection provided by the claimed invention. These theories may not be necessary or practical to use the present invention. It should also be understood that the present invention may lead to new and heretofore unknown theories to explain the functional characteristics of the embodiments of the methods, articles, materials, devices, and systems of the present invention; these later developed theories should not limit the scope of protection provided by the present invention.

[0029] The multiple embodiments of the systems, devices, techniques, methods, activities and operations described in this specification can be used in a variety of other activities and other fields beyond those described herein. In addition, these embodiments can be used, for example, with the following: other devices or activities that may be developed in the future; and, with existing devices or activities that can be partially modified based on the teachings of this specification. In addition, the multiple embodiments and examples described in this specification can be used in whole or in part with each other, and can be used in different and multiple combinations. Therefore, the configurations provided in the multiple embodiments of this specification can be used with each other. For example, according to the teachings of this specification, components of the embodiments with A, A' and B and components of the embodiments with A", C and D can be used with each other in multiple combinations, such as A, C, D and A, A", C and D, etc. Therefore, the scope of protection provided by the present invention should not be limited to specific embodiments, or the configurations or arrangements described in the embodiments in specific embodiments, examples or specific drawings.

[0030] As used herein, unless otherwise specified, the term specific gravity, also known as apparent density, should be given its broadest possible meaning and generally refers to the weight per unit volume of a structure (e.g., the bulk shape of a material). This property will include the internal pores of the particle as a fraction of its volume. It can be measured with a low viscosity fluid that wets the surface of the particle, as well as other techniques.

[0031] As used herein, unless otherwise indicated, the term actual density, which may also be referred to as true density, should be given its broadest possible meaning and generally refers to the weight of a material per unit volume when no voids are present in the material. This measurement and property is substantially minus any internal porosity of the material, e.g., it does not include any voids in the material.

[0032] Therefore, porous foam balls (e.g. spheres) can be used to illustrate the relationship between the three density properties. The weight of the spheres filling the container is the bulk density of the spheres:

[0033]

[0034] The weight of a single ball divided by the spherical volume of that ball is its apparent density:

[0035]

[0036] The weight of the material that makes up the skeleton of the sphere (i.e. the sphere with all void volume removed) divided by the remaining volume of that material is the skeleton density:

[0037]

[0038] As used herein, unless otherwise indicated, the terms agglomerate and aggregate should be given their broadest possible meaning and generally refer to a collection of particles in a powder.

[0039] The following examples are provided to illustrate various embodiments of the systems and methods of the present invention. These examples are for illustrative purposes, may be prophetic, and should not be considered limiting, and do not otherwise limit the scope of the present invention.

[0040] Various embodiments related to the use of direct reduced iron (DRI) as a material in a battery (or cell), as a component of a battery (or cell), and combinations and variations of these are discussed. In various embodiments, DRI can be produced from a material obtained from the reduction of a natural or processed iron ore without reaching the melting temperature of iron, or can be a material obtained from the reduction of a natural or processed iron ore. In various embodiments, the iron ore can be taconite or magnetite or hematite or goethite, etc. In various embodiments, DRI can be in the form of pellets, which can be spherical or substantially spherical. In various embodiments, DRI can be porous, containing open and / or closed internal pores. In various embodiments, DRI can contain material that has been further processed by hot or cold briquetting. In various embodiments, DRI can be produced by reducing iron ore pellets to form a more metallic (more reducible, less highly oxidized) material, such as iron metal (Fe 0 ), pyrite (FeO), or a composite pellet comprising an iron metal and a residual oxide phase. In a number of non-limiting embodiments, DRI can be reduced iron ore taconite, directly reduced ("DR") taconite, reduced "blast furnace (BF) grade" pellets, reduced "electric arc furnace (EAF) grade" pellets, "cold direct reduced iron (CDRI)" pellets, direct reduced iron ("DRI") pellets, hot briquette iron (HBI), or any combination thereof. In the iron and steelmaking industries, DRI is sometimes referred to as "sponge iron"; this usage is particularly common in India.

[0041] Although the term "sponge iron" is used in the specific case of direct reduction in the steelmaking industry, sponge iron is a broader class of iron-based materials. Sponge iron can be any material formed by solid-state reduction of iron, and its iron-based structure has a greater porosity than before reduction. Sponge iron is not necessarily made from ore. Instead, sponge iron can be made from any Fe-O species that can form a porous structure by reduction. Such raw materials may include mill scales, acid digestion and purification raw materials, and sintered materials, ores, processed ores or any other Fe-O species suitable for forming a structure with increased porosity by reduction.

[0042] Embodiments of iron materials (including, for example, embodiments of DRI materials) used in the various embodiments described herein (including as electrode materials) may have one, more than one, or all of the material properties described in Table 1 below. As used in this specification (including Table 1), unless otherwise expressly stated, the following terms have the following meanings: "specific surface area" refers to the total surface area of ​​the material per unit mass, including the surface area of ​​pores in the porous structure; "carbon content" or "carbon (wt%)" refers to the mass of total carbon as a percentage of the total mass of DRI; "cementite content" or "cementite (wt%)" refers to the mass of Fe3C as a percentage of the total mass of DRI; "total Fe (wt%)" refers to the mass of total iron as a percentage of the total mass of DRI; "metallic Fe (wt%)" refers to Fe 0 The percentage of the mass of iron in the Fe state to the total mass of DRI; “metallization” refers to the 0 Unless otherwise stated, weight and volume percentages and apparent densities used herein should be understood to exclude any electrolyte that has penetrated the pores or fugitive additives within the pores.

[0043] Table 1

[0044]

[0045]

[0046] *Specific surface area is preferably determined by the Brunauer-Emmett-Teller adsorption method ("BET"), more preferably BET as described in ISO 9277 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests such as methylene blue (MB) staining, ethylene glycol monoethyl ether (EGME) adsorption, electrokinetic analysis of complex ion adsorption, and protein retention (PR) methods can be used to provide results that can be correlated with BET results.

[0047] ** Actual density is preferably determined by helium (He) pycnometry, more preferably as described in ISO 12154 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests may be employed to provide results that can be correlated with He pycnometry results. Actual density may also be referred to in the art as "true density" or "skeletal density."

[0048] ***Apparent density is preferably determined by immersion in water, more preferably as described in ISO 15968 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests may be employed to provide results that can be correlated with the He pycnometer results. Porosity may be defined as the ratio of apparent density to actual density:

[0049]

[0050] ****d 孔，90％体积 , preferably determined by mercury (Hg) intrusion porosimetry, more preferably as described in ISO 15901-1 (the entire disclosure of which is incorporated herein by reference); it being recognized that other tests such as gas adsorption may be employed to provide results that can be correlated with Hg intrusion results. d 孔，90％体积 It is the pore size above which 90% of the total pore volume exists.

[0051] *****d 孔，50％表面积 , preferably determined by mercury (Hg) intrusion porosimetry, more preferably as described in ISO 15901-1 (the entire disclosure of which is incorporated herein by reference); it being recognized that other tests such as gas adsorption may be employed to provide results that can be correlated with Hg intrusion results. d 孔，50％表面积 It is the pore size above which 50% of the surface area is free.

[0052] #Total Fe (wt%) is preferably determined by dichromate titration, more preferably as described in ASTM E246-10 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests such as tin (II) chloride reduction titration, titanium (III) chloride reduction titration, inductively coupled plasma (ICP) spectroscopy can be used to provide results that can be correlated with dichromate titration.

[0053] ##Metallic Fe (wt%) is preferably determined by iron (III) chloride titration, more preferably as described in ISO 16878 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests such as bromine-methanol titration may be employed to provide results that can be correlated to iron (III) chloride titration.

[0054] ###Metallation (%) is preferably determined by the ratio of metallic Fe to total Fe, each preferably determined by the aforementioned method.

[0055] ####Carbon (wt%) is preferably determined by infrared absorption after combustion in an induction furnace, more preferably as described in ISO 9556 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests such as various combustion and inert gas fusion techniques (such as described in ASTM E1019-18) may be employed to provide results that can be correlated to infrared absorption after combustion in an induction furnace.

[0056] #####Fe 2+ (wt %) is preferably determined by titration, more preferably as described in ASTM D3872-05 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests such as Mössbauer spectroscopy, X-ray absorption spectroscopy, etc. can be employed to provide results that can be correlated with titration.

[0057] $Fe 3+ (wt%) is preferably determined by total Fe (wt%), metallic Fe (wt%), Fe 2+ (wt%) and Fe 3+ Specifically, the equation total Fe (wt%) = metallic Fe (wt%) + Fe 2+ (wt%) +Fe 3+ (weight %) is certain to hold due to the law of conservation of mass, so Fe 3+ (weight %) can be calculated as: Fe 3+ (weight %) = total Fe (weight %) - metallic Fe (weight %) - Fe 2+ (weight%).

[0058] $$SiO2 (wt%) is preferably determined by gravimetric analysis, more preferably as described in ISO 2598-1 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests such as reduced molybdenum silicate spectrophotometry, x-ray diffraction (XRD) may be employed to provide results that can be correlated with gravimetric analysis. In certain methods, the SiO2 wt% is not determined directly, but rather the Si concentration (including neutral and ionic species) is measured and the SiO2 wt% is calculated assuming a stoichiometric SiO2, i.e., assuming a Si:O molar ratio of 1:2.

[0059] $$$ Ferrite (wt %, XRD) is preferably determined by x-ray diffraction (XRD).

[0060] $$$$Wuxite (FeO, wt. %, XRD) is preferably determined by x-ray diffraction (XRD).

[0061] $$$$$Goethite (FeOOH, wt. %, XRD) is preferably determined by x-ray diffraction (XRD).

[0062] + Cementite (Fe3C, wt. %, XRD) is preferably determined by x-ray diffraction (XRD).

[0063] Additionally, embodiments of iron materials (including, for example, embodiments of DRI materials) for use in the various embodiments described herein (including as electrode materials) can have one or more of the following characteristics, features, or properties as described in Table 1A (note that values ​​from one row or column can appear with values ​​in a different row or column).

[0064] Table 1A

[0065]

[0066] Total Fe (wt%) is preferably determined by dichromate titration, more preferably as described in ASTM E246-10 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests such as tin (II) chloride reduction titration, titanium (III) chloride reduction titration, inductively coupled plasma (ICP) spectroscopy can be used to provide results that can be correlated with dichromate titration.

[0067] ! ! SiO2 (wt%) is preferably determined by gravimetric analysis, more preferably as described in ISO 2598-1 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests such as reduced molybdenum silicate spectrophotometry, x-ray diffraction (XRD) can be used to provide results that can be correlated with gravimetric analysis. In some methods, the SiO2 wt% is not determined directly, but the Si concentration (including neutral and ionic species) is measured and the SiO2 wt% is calculated assuming a stoichiometric SiO2, i.e., assuming a Si:O molar ratio of 1:2.

[0068] !!!Al2O3 (wt%) is preferably determined by flame atomic absorption spectrometry, more preferably as described in ISO 4688-1 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests such as X-ray diffraction (XRD) may be employed to provide results that correlate with flame atomic absorption spectrometry. In certain methods, the Al2O3 wt% is not determined directly, but the Al concentration (including neutral and ionic species) is measured and the Al2O3 wt% is calculated assuming a stoichiometric Al2O3, i.e., assuming a molar ratio of Al:O of 2:3.

[0069] MgO (wt%) is preferably determined by flame atomic absorption spectrometry, more preferably as described in ISO 10204 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests such as X-ray diffraction (XRD) may be employed to provide results that can be correlated with flame atomic absorption spectrometry. In certain methods, MgO wt% is not determined directly, but rather the Mg concentration (including neutral and ionic species) is measured and the MgO wt% is calculated assuming a stoichiometric MgO, i.e., assuming a Mg:O molar ratio of 1:1.

[0070] !!!!!! CaO (wt%) is preferably determined by flame atomic absorption spectrometry, more preferably as described in ISO 10203 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests such as X-ray diffraction (XRD) may be employed to provide results that can be correlated with flame atomic absorption spectrometry. In certain methods, the CaO wt% is not determined directly, but rather the Ca concentration (including neutral and ionic species) is measured and the CaO wt% is calculated assuming a stoichiometric CaO, i.e., assuming a Ca:O molar ratio of 1:1.

[0071] & TiO2 (wt%) is preferably determined by diantipyryl methane spectrophotometry, more preferably as described in ISO 4691 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests such as X-ray diffraction (XRD) may be employed to provide results that can be correlated with diantipyryl methane spectrophotometry. In certain methods, TiO2 wt% is not determined directly, but the Ti concentration (including neutral and ionic species) is measured and the TiO2 wt% is calculated assuming a stoichiometric TiO2, i.e., assuming a Ti:O molar ratio of 1:2.

[0072] &&The actual density is preferably determined by helium (He) pycnometer method, more preferably as described in ISO 12154 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests may be employed to provide results that can be correlated with He pycnometer results. The actual density may also be referred to in the art as "true density" or "skeletal density".

[0073] &&&The apparent density is preferably determined by immersion in water, more preferably as described in ISO 15968 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests may be employed to provide results that can be correlated with the He pycnometer results.

[0074] &&&&Volume density (kg / m 3 ) is preferably determined by measuring the mass of a test portion introduced into a container of known volume up to the level of its surface, more preferably as described in method 2 of ISO 3852 (the entire disclosure of which is incorporated herein by reference); it being recognized that other tests may be employed to provide results that can be correlated with mass methods.

[0075] &&&&&&Porosity is preferably determined by the ratio of apparent density to actual density:

[0076]

[0077] The properties described in Table 1 may also be present in embodiments together with, in addition to, or in place of the properties in Table 1A. Greater and lesser values ​​of these properties may also be present in various embodiments.

[0078] In embodiments, the specific surface area of ​​the pellets may be about 0.05 m 2 / g to about 35m 2 / g, about 0.1m 2 / g to about 5m 2 / g, about 0.5m 2 / g to about 10m 2 / g, about 0.2m 2 / g to about 5m2 / g, about 1m 2 / g to about 5m 2 / g, about 1m 2 / g to about 20m 2 / g, greater than about 1m 2 / g, greater than about 2m 2 / g, less than about 5m 2 / g, less than about 15m 2 / g, less than about 20m 2 / g, and combinations and variations of these ranges, as well as larger and smaller values.

[0079] Typically, iron ore pellets are produced by crushing, grinding or grinding the iron ore into a fine powder form and then refining it by removing the impurity phases (so-called "gangue") released by the grinding operation. Typically, as the ore is ground into finer (smaller) particle sizes, the purity of the resulting concentrate increases. The concentrate is then formed into pellets by a granulation or pelletizing process (using, for example, a drum or pan granulator). Typically, a greater energy input is required to produce higher purity ore pellets. Iron ore pellets are typically marketed or sold in two main categories, namely blast furnace (BF) grade pellets and direct reduction (DR grade) (sometimes also referred to as electric arc furnace (EAF) grade), the main difference being that the content of SiO2 and other impurity phases in the BF grade pellets is higher relative to the DR grade pellets. Typical key specifications for DR grade pellets or raw materials are a total Fe content in the range of 6369 wt% to 69 wt%, such as 67 wt%, and a SiO2 content in the mass percentage of less than 3 wt%, such as 1 wt%. Typical key specifications for BF grade pellets or feedstock are a total Fe content in the range of 60 to 67 wt%, such as 63 wt%, and a SiO2 content in the range of 2 to 8 wt%, such as 4 wt%, in mass%.

[0080] In certain embodiments, DRI may be produced by reduction of "blast furnace" pellets, in which case the resulting DRI may have the material properties described below in Table 2. Using reduced BF grade DRI may be advantageous because less input energy is required to produce the pellets, which translates into lower cost for the finished material.

[0081] Table 2

[0082] Material properties Scope of implementation plan <![CDATA[Specific surface area * > <![CDATA[0.21-25m 2 / g]]> <![CDATA[Actual density ** > 5.5-6.7g / cc <![CDATA[Apparent density *** > 3.1-4.8g / cc <![CDATA[Minimum d 孔，90％体积 **** > 50nm-50μm <![CDATA[Minimum d 孔，50％表面积 ***** > 1nm-10μm <![CDATA[Total iron (wt%) # > 81.8-89.2％ <![CDATA[Iron metal (wt%) ## > 68.7-83.2％ <![CDATA[Degree of Metallization (%) ### > 84-95％ <![CDATA[Carbon (% by weight) #### > 0.03-0.35％ <![CDATA[Fe 2+ (weight%) ##### ]]> 2-8.7％ <![CDATA[Fe 3+ (weight%) $ ]]> 0.9-5.2％ <![CDATA[SiO2 (wt%) $$ > 3-7％ <![CDATA[Ferrite (wt%, XRD) $$$ > 80-96％ <![CDATA[Wüstite (FeO, wt%, XRD) $$$$ > 2-13％ <![CDATA[Goethite (FeOOH, wt%, XRD) $$$$$ > 0-11％ <![CDATA[Cementite (Fe3C, wt%, XRD) + > 0-80％

[0083] *Specific surface area is preferably determined by the Brunauer-Emmett-Teller adsorption method ("BET"), more preferably BET as described in ISO 9277 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests, such as methylene blue (MB) staining, ethylene glycol monoethyl ether (EGME) adsorption, electrokinetic analysis of complex ion adsorption, and protein retention (PR) methods can be used to provide results that can be correlated with BET results.

[0084] ** Actual density is preferably determined by helium (He) pycnometry, more preferably as described in ISO 12154 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests may be employed to provide results that can be correlated with He pycnometry results. Actual density may also be referred to in the art as "true density" or "skeletal density."

[0085] ***Apparent density is preferably determined by immersion in water, more preferably as described in ISO 15968 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests may be employed to provide results that can be correlated with the He pycnometer results. Porosity may be defined as the ratio of apparent density to actual density:

[0086]

[0087] ****d 孔，90％体积 , preferably determined by mercury (Hg) intrusion porosimetry, more preferably as described in ISO 15901-1 (the entire disclosure of which is incorporated herein by reference); it being recognized that other tests such as gas adsorption may be employed to provide results that can be correlated with Hg intrusion results. d 孔，90％体积 It is the pore size above which 90% of the total pore volume exists.

[0088] *****d 孔，50％表面积 , preferably determined by mercury (Hg) intrusion porosimetry, more preferably as described in ISO 15901-1 (the entire disclosure of which is incorporated herein by reference); it being recognized that other tests such as gas adsorption may be employed to provide results that can be correlated with Hg intrusion results. d 孔，50％表面积 It is the pore size above which 50% of the surface area is free.

[0089] #Total Fe (wt%) is preferably determined by dichromate titration, more preferably as described in ASTM E246-10 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests such as tin (II) chloride reduction titration, titanium (III) chloride reduction titration, inductively coupled plasma (ICP) spectroscopy can be used to provide results that can be correlated with dichromate titration.

[0090] ##Metallic Fe (wt%) is preferably determined by iron (III) chloride titration, more preferably as described in ISO 16878 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests such as bromine-methanol titration may be employed to provide results that can be correlated to iron (III) chloride titration.

[0091] ###Metallation (%) is preferably determined by the ratio of metallic Fe to total Fe, each preferably determined by the aforementioned method.

[0092] ####Carbon (wt%) is preferably determined by infrared absorption after combustion in an induction furnace, more preferably as described in ISO 9556 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests such as various combustion and inert gas fusion techniques (such as described in ASTM E1019-18) may be employed to provide results that can be correlated to infrared absorption after combustion in an induction furnace.

[0093] #####Fe 2+ (wt %) is preferably determined by titration, more preferably as described in ASTM D3872-05 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests such as Mössbauer spectroscopy, X-ray absorption spectroscopy, etc. can be employed to provide results that can be correlated with titration.

[0094] Fe 3+ (wt%) is preferably determined by total Fe (wt%), metallic Fe (wt%), Fe 2+ (wt%) and Fe 3+ Specifically, the equation total Fe (wt%) = metallic Fe (wt%) + Fe 2+ (wt%) +Fe 3+ (weight %) is certain to hold due to the law of conservation of mass, so Fe 3+ (weight %) can be calculated as: Fe 3+ (weight %) = total Fe (weight %) - metallic Fe (weight %) - Fe 2+ (weight%).

[0095] $$SiO2 (wt%) is preferably determined by gravimetric analysis, more preferably as described in ISO 2598-1 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests such as reduced molybdenum silicate spectrophotometry, x-ray diffraction (XRD) may be employed to provide results that can be correlated with gravimetric analysis. In certain methods, the SiO2 wt% is not determined directly, but rather the Si concentration (including neutral and ionic species) is measured and the SiO2 wt% is calculated assuming a stoichiometric SiO2, i.e., assuming a Si:O molar ratio of 1:2.

[0096] $$$ Ferrite (wt %, XRD) is preferably determined by x-ray diffraction (XRD).

[0097] $$$$Wuxite (FeO, wt. %, XRD) is preferably determined by x-ray diffraction (XRD).

[0098] $$$$$Goethite (FeOOH, wt. %, XRD) is preferably determined by x-ray diffraction (XRD).

[0099] + Cementite (Fe3C, wt. %, XRD) is preferably determined by x-ray diffraction (XRD).

[0100] The characteristics described in Table 2 may also be present in embodiments together with, or in addition to or in place of, the characteristics in Table 1 and / or Table 1A. Greater and lesser values ​​of these characteristics may also be present in multiple embodiments.

[0101] In certain embodiments, DRI can be produced by reduction of DR grade pellets, in which case the resulting DRI can have material properties as described below in Table 3. Using reduced DR grade DRI can be advantageous because the iron content in the pellets is higher, which increases the energy density of the battery.

[0102] Table 3

[0103]

[0104]

[0105] *Specific surface area is preferably determined by the Brunauer-Emmett-Teller adsorption method ("BET"), more preferably BET as described in ISO 9277 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests, such as methylene blue (MB) staining, ethylene glycol monoethyl ether (EGME) adsorption, electrokinetic analysis of complex ion adsorption, and protein retention (PR) methods can be used to provide results that can be correlated with BET results.

[0106] ** Actual density is preferably determined by helium (He) pycnometer method, more preferably as described in ISO 12154 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests may be employed to provide results that can be correlated with He pycnometer results. Actual density may also be referred to in the art as "true density" or "skeletal density".

[0107] ***Apparent density is preferably determined by immersion in water, more preferably as described in ISO 15968 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests may be employed to provide results that can be correlated with the He pycnometer results. Porosity may be defined as the ratio of apparent density to actual density:

[0108]

[0109] ****d 孔，90％体积 , preferably determined by mercury (Hg) intrusion porosimetry, more preferably as described in ISO 15901-1 (the entire disclosure of which is incorporated herein by reference); it being recognized that other tests such as gas adsorption may be employed to provide results that can be correlated with Hg intrusion results. d 孔，90％体积 It is the pore size above which 90% of the total pore volume exists.

[0110] *****d 孔，50％表面积 , preferably determined by mercury (Hg) intrusion porosimetry, more preferably as described in ISO 15901-1 (the entire disclosure of which is incorporated herein by reference); it being recognized that other tests such as gas adsorption may be employed to provide results that can be correlated with Hg intrusion results. d 孔，50％表面积 It is the pore size above which 50% of the surface area is free.

[0111] #Total Fe (wt%) is preferably determined by dichromate titration, more preferably as described in ASTM E246-10 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests such as tin (II) chloride reduction titration, titanium (III) chloride reduction titration, inductively coupled plasma (ICP) spectroscopy can be used to provide results that can be correlated with dichromate titration.

[0112] ##Metallic Fe (wt%) is preferably determined by iron (III) chloride titration, more preferably as described in ISO 16878 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests such as bromine-methanol titration may be employed to provide results that can be correlated to iron (III) chloride titration.

[0113] ###Metallation (%) is preferably determined by the ratio of metallic Fe to total Fe, each preferably determined by the aforementioned method.

[0114] ####Carbon (wt%) is preferably determined by infrared absorption after combustion in an induction furnace, more preferably as described in ISO 9556 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests such as various combustion and inert gas fusion techniques (such as described in ASTM E1019-18) may be employed to provide results that can be correlated to infrared absorption after combustion in an induction furnace.

[0115] #####Fe 2+ (wt %) is preferably determined by titration, more preferably as described in ASTM D3872-05 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests such as Mössbauer spectroscopy, X-ray absorption spectroscopy, etc. can be employed to provide results that can be correlated with titration.

[0116] $Fe 3+ (wt%) is preferably determined by total Fe (wt%), metallic Fe (wt%), Fe 2+ (wt%) and Fe 3+ Specifically, the equation total Fe (wt%) = metallic Fe (wt%) + Fe 2+ (wt%) +Fe 3+ (weight %) is certain to hold due to the law of conservation of mass, so Fe 3+ (weight %) can be calculated as: Fe 3+ (weight %) = total Fe (weight %) - metallic Fe (weight %) - Fe 2+ (weight%).

[0117] $$SiO2 (wt%) is preferably determined by gravimetric analysis, more preferably as described in ISO 2598-1 (the entire disclosure of which is incorporated herein by reference); it is recognized that other tests such as reduced molybdenum silicate spectrophotometry, x-ray diffraction (XRD) may be employed to provide results that can be correlated with gravimetric analysis. In certain methods, the SiO2 wt% is not determined directly, but rather the Si concentration (including neutral and ionic species) is measured and the SiO2 wt% is calculated assuming a stoichiometric SiO2, i.e., assuming a Si:O molar ratio of 1:2.

[0118] $$$ Ferrite (wt %, XRD) is preferably determined by x-ray diffraction (XRD).

[0119] $$$$Wuxite (FeO, wt. %, XRD) is preferably determined by x-ray diffraction (XRD).

[0120] $$$$$Goethite (FeOOH, wt. %, XRD) is preferably determined by x-ray diffraction (XRD).

[0121] + Cementite (Fe3C, wt. %, XRD) is preferably determined by x-ray diffraction (XRD).

[0122] The characteristics described in Table 3 may also be present in embodiments together with, or in addition to or in place of, the characteristics in Table 1, Table 1A, and / or Table 2. Greater and lesser values ​​of these characteristics may also be present in various embodiments.

[0123] Electrochemical cells, such as batteries, store electrochemical energy by utilizing an electrochemical potential that creates a voltage difference between a positive electrode and a negative electrode. If the electrodes are connected by a conductive element, this voltage difference generates an electric current. In a battery, the negative and positive electrodes are connected in series by external and internal resistive elements. Typically, the external element conducts electrons and the internal element (electrolyte) conducts ions. Since the charge imbalance cannot be maintained between the negative and positive electrodes, the two flows must provide ions and electrons at the same rate. In operation, the electron flow can be used to drive external devices. Rechargeable batteries can be recharged by applying a reverse voltage difference, which drives a current and ion flow in the opposite direction to the discharged battery in use.

[0124] Embodiments of the present invention include devices, systems and methods for long-term and ultra-long-term, low-cost energy storage. In this article, "long-term" and / or "ultra-long-term" may refer to energy storage periods of 8 hours or longer, such as an energy storage period of 8 hours, an energy storage period of 8 hours to 20 hours, an energy storage period of 20 hours, an energy storage period of 20 hours to 24 hours, an energy storage period of 24 hours, an energy storage period of 24 hours to a week, an energy storage period of a week to a year (e.g., from a few days to a few weeks to a few months), etc. In other words, "long-term" and / or "ultra-long-term" energy storage batteries may refer to electrochemical cells that can be configured to store energy for a time span of several days, weeks, or seasons. For example, an electrochemical cell may be configured to store energy generated by a solar cell when the sun is abundant in the summer and solar power generation exceeds grid demand, and release the stored energy when the sun may not be sufficient to meet grid demand in the winter.

[0125] Typically, in embodiments, the long-term energy storage battery can be a long-term electrochemical battery. Typically, such a long-term electrochemical battery can store electricity generated by a power generation system in the following situations: (i) the energy source or fuel used for the power generation is available, abundant, cheap, and combinations and variations of these; (ii) when the energy requirements or power demand of the power grid, customers or other users are less than the amount of electricity generated by the power generation system, the price paid for providing such energy to the power grid, customers or other users is lower than the economic efficiency point of generating such energy (for example, the cost of power generation exceeds the market price of electricity), and combinations and variations of these; and (iii) combinations and variations of (i) and (ii) and other reasons. Then, when it is economically feasible or there is other need, the electricity stored in the long-term electrochemical battery can be distributed to the power grid, customers or other users. For example, the electrochemical cell can be configured to store energy generated by solar cells when the sun is abundant in the summer and solar power generation exceeds the demand of the power grid, and release the stored energy when the sun may not be enough to meet the demand of the power grid in the winter.

[0126] According to other embodiments, the present invention includes devices, systems and methods for shorter energy storage of less than about 8 hours. For example, the electrochemical cell can be configured to store energy generated by a solar cell during a diurnal cycle, where solar power generation at noon may exceed grid demand, and release the stored energy in the evening when sunlight may not be sufficient to meet grid demand. As another example, the invention can include energy storage used as a backup power source when the power supplied by the grid is insufficient, for facilities including homes, commercial buildings, factories, hospitals or data centers, where the required discharge duration can range from a few minutes to several days.

[0127] In some embodiments, the electrochemical cell comprises a negative electrode, a positive electrode, an electrolyte, and a separator (e.g., Figure 1 shown). Figure 1 An exemplary electrochemical cell 100, such as a battery, is shown, comprising a negative electrode and electrolyte 102, which are separated from a positive electrode and electrolyte 103 by a separator 104. The separator 104 can be supported by a polypropylene mesh 105 and a polyethylene frame 108 of the cell 100. A current collector 107 can be associated with the respective electrodes of the negative electrode 102 and the positive electrode 103 and supported by a polyethylene backing 106. In some embodiments, the temperature of the electrochemical cell 100 can be controlled, for example, by insulation around the cell 100 and / or a heater 150. For example, the heater 150 can increase the temperature of the cell 100 and / or specific components of the cell, such as the electrolytes 102, 103. Figure 1 The configuration of the electrochemical cell 100 in is merely an example of one electrochemical cell configuration according to various embodiments and is not intended to be limiting. Other configurations, such as electrochemical cells with different types of mesh and / or without polypropylene mesh 105, electrochemical cells with different types of frames and / or without polyethylene frames 108, electrochemical cells with different types of current collectors and / or without current collectors, electrochemical cells with different types of backsheets and / or without polyethylene backsheets 106, electrochemical cells with different types of insulation and / or without insulation, and / or electrochemical cells with different types of heaters and / or without heaters 150 may be substituted. Figure 1 An exemplary configuration of electrochemical cell 100 is shown, and other configurations are consistent with various embodiments.

[0128] In some embodiments, multiple Figure 1 The electrochemical cells 100 in the stack can be electrically connected in series to form a stack. In certain other embodiments, multiple electrochemical cells 100 can be electrically connected in parallel. In certain other embodiments, the electrochemical cells 100 are connected in a mixed series-parallel electrical configuration to achieve a favorable combination of delivered current and voltage.

[0129] According to a plurality of embodiments, the negative electrode comprises a pelletized, briquette, pressed or sintered iron-containing compound. Such iron-containing compounds may include one or more forms of iron, ranging from highly reduced (more metallic) iron to highly oxidized (more ionic) iron. In a plurality of embodiments, the pellets may include a variety of iron compounds, such as iron oxides, hydroxides, sulfides, carbides or combinations thereof. In a plurality of embodiments, the negative electrode may be a sintered iron agglomerate with a variety of shapes. In some embodiments, atomized iron powder or sponge iron powder may be used as a raw material for forming a sintered iron electrode. In some embodiments, the green body may also include a binder, such as a polymer or an inorganic clay-like material. In a plurality of embodiments, sintered iron agglomerate pellets may be formed in a furnace (e.g., a continuously fed calciner, a batch fed calciner, a shaft furnace, a rotary calciner, a rotary hearth furnace, etc.). In a plurality of embodiments, the pellets may include a reduced and / or sintered iron-containing precursor known to those skilled in the art as direct reduced iron (DRI), and / or its byproduct materials. Various embodiments may include treating the pellets, including DRI pellets, using electrical, electrochemical, mechanical, chemical, and / or thermal processes prior to introducing the pellets into an electrochemical cell.

[0130] According to various embodiments, an electrochemical cell, e.g. Figure 1 The battery 100 comprises a negative electrode (also referred to as an anode), a positive electrode (also referred to as a cathode) and an electrolyte. The negative electrode may be an iron material. The electrolyte may be an aqueous solution. In certain embodiments, the electrolyte may be an alkaline solution (pH>10). In certain embodiments, the electrolyte may be a near-neutral solution (10>pH>4).

[0131] In one example, the half-cell reactions occurring at the negative electrode during discharge and oxidation in an alkaline electrolyte are: Step 1) (OH )2 +2e - ; and step 2) In step 1 (also referred to herein as "step 1 reaction" or "reaction step 1"), ferrous hydroxide may be formed on the surface of the iron forming the negative electrode. In step 2 (also referred to herein as "step 2 reaction" or "reaction step 2"), the ferrous hydroxide is then further oxidized to form magnetite. There is a net volume increase upon discharge, which is absorbed by the pores of the negative electrode. According to the negative electrode reaction in this example, the theoretical capacity of metallic iron is 960 mAh / gFe in step 1 and 320 mAh / gFe in step 2.

[0132] Iron-based electrodes (also known as Fe anodes) are difficult to recharge due to competition with hydrogen evolution (H2), a side reaction that does not result in recharging of the battery because the electrons are transferred to the H2 instead of being stored in the more reducing iron-containing negative electrode. In addition, the ability of electrons to move through the anode can also hinder the charging and discharging reactions. When there are no or limited pathways for electrons to move through the anode, the charging and discharging efficiency of the anode can be reduced. Another issue that can hinder the recharging of iron-based electrodes is pore clogging. In some cases, methods of increasing the surface area of ​​iron-based anodes can also lead to pore clogging of the anode. When the pores of the anode are clogged, ions cannot enter and exit the anode, and the anode cannot be recharged. Coupled with the difficulty of recharging iron anodes, this clogging can lead to a huge loss in specific discharge capacity.

[0133] In various embodiments, one or more additives such as lead (Pb), tin (Sn), antimony (Sb), copper (Cu), silver (Ag), gold (Au), etc. can be added to the electrochemical cell. Adding one or more additives according to various embodiments can improve the charging of the iron-based negative electrode (Fe anode). In various embodiments, the one or more additives may include such elements, which have a low hydrogen evolution reaction (HER) in their metallic form. In various embodiments, the electrochemical cell to which the one or more additives are added may include an electrolyte containing one or more hydroxides. In various embodiments, the electrochemical cell to which the one or more additives are added may include an electrolyte that does not include a hydroxide.

[0134] In various embodiments, additives that inhibit hydrogen evolution, such as metals with low hydrogen evolution reaction (HER) activity (e.g., lead (Pb), tin (Sn), antimony (Sb), indium (In), etc.) can be added to the electrochemical cell to improve the charging of the iron-based negative electrode (Fe anode). In various embodiments, additives that inhibit hydrogen evolution, such as metals with low hydrogen evolution reaction (HER) activity (e.g., lead (Pb), tin (Sn), antimony (Sb), indium (In), etc.) can be added to the electrolyte and / or the anode of the electrochemical cell.

[0135] Low hydrogen evolution reaction (HER) activity additives can be defined relative to the HER activity of iron. In a first example, an additive having a hydrogen evolution reaction (HER) exchange current density lower than that of iron can be considered a low hydrogen evolution reaction (HER) activity additive. In a second example, a battery comprising a low HER activity additive has a reduced hydrogen evolution rate (e.g., measured by in situ sensing of hydrogen production) in the battery compared to a battery that does not contain a low HER activity additive. In a third example, a battery comprising a low HER activity additive produces less hydrogen at a given state of charge than a comparable battery that does not contain a low HER activity additive. In one set of examples, the significantly reduced HER activity can be a 50% or more reduction in HER activity. In another set of examples, the significantly reduced hydrogen production can be a 10% or more reduction in HER activity.

[0136] The low HER activity additive can also be defined by the coulombic efficiency of a cell containing an iron anode. The low HER activity additive will increase the coulombic efficiency of the cell compared to a cell containing only an iron anode material. The significantly higher coulombic efficiency can be ≥5% higher than a cell containing only an anode material. In various embodiments, the low HER activity additive can be added to the electrochemical cell in solid form (e.g., metallic form) and / or in liquid form.

[0137] In various embodiments, additives that improve the conductive network in the iron anode, such as highly conductive metals (tin (Sn), copper (Cu), indium (In), silver (Ag), gold (Au)) or derivatives thereof, can be added to the electrochemical cell to improve the charging of the iron-based negative electrode (Fe anode). In various embodiments, additives that improve the conductive network in iron, such as highly conductive metals (tin (Sn), copper (Cu), indium (In), silver (Ag), gold (Au)) or derivatives thereof, can be added to the electrolyte and / or the anode of the electrochemical cell. The highly conductive metal can be a metal element with a resistivity of less than 125 nano-ohm meters (nΩ·m).

[0138] In various embodiments, additives that help retain other additives in the electrode or electrolyte (e.g., lead (Pb), tin (Sn), antimony (Sb), indium (In), etc.) can be added to the electrochemical cell to improve the charging of the iron-based negative electrode (Fe anode). These additives can form soluble or slightly soluble complexes or solid compounds with other additives present in the cell. In various embodiments, metals that form complexes with other additives in solution (e.g., lead (Pb), tin (Sn), antimony (Sb), indium (In), or derivatives thereof) can be added to the electrolyte and / or anode of the electrochemical cell.

[0139] In various embodiments, additives such as tin (Sn) that improve the reversibility of Fe(II) to Fe(0) can be added to electrochemical cells to improve the charging of iron-based negative electrodes (Fe anodes).

[0140] In various embodiments, additives incorporated into the Fe anode or present in the conditioning process can be added to the electrochemical cell to improve the charging of the iron-based negative electrode (Fe anode). Without being bound by a particular theory, the conditioning process is a step in which the surface area and interconnectivity of the Fe anode surface change. This conditioning process can be achieved by a thorough discharge of several cycles by reaction steps 1 and 2 or only reaction step 1 before the battery reaches the rated discharge capacity (>200mAh / g, 200-250mAh / g, >250mAh / g, 250-300mAh / g, >300mAh / g, 300-350mAh / g, >350mAh / g, 350-400mAh / g, >400mAh / g, etc.). Thereafter, the anode can be reversibly cycled with high capacity and high efficiency as required by the application. The presence and / or incorporation of additives such as Sn, Sb, In, Cu, Ag, Au in the anode can improve discharge capacity and efficiency. Although reaction steps 1 and / or 2 are associated with the conditioning process, the conditioning process may not be so limited and may not require additional reactions and / or different reactions beyond reaction steps 1 and / or 2. Charging of an iron-based negative electrode (Fe anode) during the conditioning process in the presence of an additive may be affected by a variety of factors, such as additive concentration (e.g., stannate concentration, etc.), charge capacity, temperature, and / or morphology / structure of the anode material.

[0141] The conditioning process can be determined based on the target discharge capacity. In a first example, the additive can increase the discharge capacity during the conditioning process to be greater than 200 mAh / g. A good conditioning additive can increase the discharge capacity after conditioning compared to the discharge capacity of a battery containing only iron anode material. A significant increase in capacity may be ≥5% compared to a battery containing only anode material. In various embodiments, the conditioning additive can be added to the electrochemical cell in solid form (such as metal form) and / or liquid form.

[0142] The conditioning process can be determined based on the number of cycles or time required to reach the target discharge capacity. In a first example, the additive can reduce the time required to reach the target discharge capacity. A good conditioning additive can reduce the number of cycles or time required to reach a given discharge capacity compared to a battery containing only iron anode material. A significant acceleration of time may be ≥5% compared to a battery containing only anode material. A significant acceleration of time may be a 5% reduction in the number of cycles compared to a battery containing only anode material. In various embodiments, the conditioning additive can be added to the electrochemical cell in solid form (such as metal form) and / or liquid form.

[0143] The conditioning process can be determined based on the ratio of the discharge capacity of reaction step 1 to the discharge capacity of reaction step 2 (the ratio of reaction step 1 / reaction step 2). In a first example, the additive can increase the ratio of reaction step 1 / reaction step 2 during the conditioning process. A good conditioning additive can increase the ratio of reaction step 1 / reaction step 2 compared to a battery containing only an iron anode material. A significant improvement in the ratio of reaction step 1 / reaction step 2 may be ≥5% compared to a battery containing only an anode material. In various embodiments, the conditioning additive can be added to the electrochemical cell in solid form (such as a metal form) and / or in liquid form.

[0144] In various embodiments, tin can be used to maintain cell performance for battery packs with different OH concentrations (4 M to 8 M). Cells with higher tin concentrations are less sensitive to total hydroxide concentration, particularly in terms of reaction-capacity fraction and voltaic efficiency.

[0145] In various embodiments, the tin depassivates the surface of a Fe anode in an electrochemical cell.

[0146] In various embodiments, tin can increase the discharge capacity of a Fe anode in an electrochemical cell.

[0147] In various embodiments, tin (Sn) and / or tin-containing compounds may be included (e.g., added, present, etc.) in an electrochemical cell, such as in an electrolyte, as part of an electrode, as a reservoir in an electrochemical cell, etc. The inclusion of tin and / or tin-containing compounds may reduce the tendency of hydrogen evolution at the iron anode, thereby promoting more efficient recharging of the iron electrode; that is, when recharging, more step 1 reaction capacity is reversed, thereby producing more metallic iron in the charged state. In the subsequent discharge step, this results in a greater step 1 reaction capacity. Without being bound by any particular scientific explanation or particular operating theory, it is believed that the increase in hydrogen evolution overpotential may be due to the deposition of tin as a metal, oxide, mixed Fe-Sn oxide, or Fe-Sn alloy on the iron anode, resulting in a decrease in HER activity on the iron anode compared to the HER activity in the absence of tin. The reduction in HER activity may also be due to alloying, the formation of surface phases, the electrodeposition of tin or tin derivatives, or the complexation of tin with the iron anode material. Regardless of the mechanism of action, a significant advantage of a battery containing tin is that the charging efficiency of the iron anode is improved compared to the charging efficiency in the absence of tin. Tin is highly soluble in alkaline solution (pH>10) electrolytes, and the inclusion of tin and / or tin-containing compounds in the electrolyte can result in tin-plated iron anodes in the electrolyte. Figure 6 This is the phase diagram of K2Sn(OH)6-KOH-H2O system at 25.0℃. Figure 6 The solid circles in the figure represent the solution composition, and the black circles represent the wet residue composition. Figure 6 As shown, the maximum solubility of 6M KOH at 25.0°C is 0.272M K2Sn(OH)6, and the maximum solubility of 10-13M OH is closer to 6mM K2Sn(OH)6. Depositing tin on the iron anode may increase the reaction capacity of step 1, that is, This may be due to the new phase FeSnO that can better recharge the iron anode. x The presence of tin in the iron anode may also introduce a secondary high potential reaction, namely Due to a more efficient or altered charging mechanism, the total high potential discharge capacity is increased. For example, the inclusion of tin and / or tin-containing compounds can increase the discharge potential of the iron anode to greater than 0.75V, greater than 0.8V, greater than 0.85V, greater than 0.9V, etc. The inclusion of tin and / or tin-containing compounds can improve the circulation of the iron anode in the electrochemical cell. In various embodiments, the tin and / or tin-containing compounds may include metallic tin, stannates, thiostannates, and / or any other tin source. As specific examples, metallic tin (Sn), sodium stannate trihydrate (Na2SnO3·3H2O), potassium stannate trihydrate (K2SnO3·3H2O), calcium stannate (CaSnO3), magnesium stannate (MgSnO3), barium stannate (BaSnO3), cobalt stannate (Co2SnO4), tin oxide (SnO2), cylindrical cassiterite (Pb3Sn4FeSb2S 14 ), silver tin sulfide (Ag8SnS6), copper iron tin sulfide (Cu2FeSnS 4 ), lead-tin alloy (60 / 40Sn / Pb solder; 63 / 37Sn / Pb solder; Terne I alloy: 10-20% Sn, the balance is Pb), zinc-tin alloy (Terne II alloy: 10-20% Sn, the balance is Zn) or tin sulfide (SnS or SnS2) can be included in the electrochemical cell, for example in the electrolyte and / or in the electrode. In various embodiments, the tin source can be a solid tin source and / or a soluble tin source. Figure 2A-2C It is Pulbaitu of Tin.

[0148] In various embodiments, tin and / or tin-containing compounds may be included as part of an electrolyte in an electrochemical cell. As an example, tin and / or tin-containing compounds may be added to the electrolyte in an amount such that the added tin and / or tin-containing compound is equal to about 0.1 millimolar (mM) to about the saturation limit of the tin and / or tin-containing compound in the electrolyte. As a specific example, tin and / or tin-containing compounds may be present in the electrolyte at the following concentrations: 0.1 mM, 0.1 mM to 10 mM, 0.1 mM to 100 mM (or 0.1 M), 10 mM, 10 mM to 100 mM (or 0.1 M), 10 mM to 50 mM, 50 mM, 50 mM to 60 mM, 10 mM to 70 mM, 10 mM to 60 mM, 50 mM to 100 mM (or 0.1 M), 50 mM to 70 mM, 60 mM to 70 mM, 60 mM, 70 mM, 70 mM to 100 mM (or 0.1 M), 10 mM to 80 mM, 50 mM to 80 mM, 60mM to 80mM, 70mM to 80mM, 80mM, 80mM to 100mM (or 0.1M), 100mM (or 0.1M), 100mM (or 0.1M) to 1M, 1M, 100mM (or 0.1M) to 750mM (or .75M), 750mM (or .75M), 100mM (or 0.1M) to 500mM (or .5M), 500mM (or .5M), 100mM (or 0.1M) to 600mM (or .6M), 600mM (or .6M), 100mM (or 0.1M) to 670mM (or .67M), 670mM (or .67M), 500mM (or 0.5M) to 670mM (or .67M), 600mM (or 0.6M) to 670mM (or .67M), 650mM (or 0.65M) to 670mM (or .67M), 650mM (or .65M), 0.1mM to the saturation limit of tin and / or tin-containing compounds in the electrolyte, 10mM to the saturation limit of tin and / or tin-containing compounds in the electrolyte, 50mM to the saturation limit of tin and / or tin-containing compounds in the electrolyte, 100mM (or 0.1M) to the saturation limit of tin and / or tin-containing compounds in the electrolyte, 500mM (or 0.5M) to the saturation limit of tin and / or tin-containing compounds in the electrolyte The saturation limit of tin and / or tin-containing compounds in the electrolyte is 600 mM (or 0.6 M) to the saturation limit of tin and / or tin-containing compounds in the electrolyte, 650 mM (or 0.65 M) to the saturation limit of tin and / or tin-containing compounds in the electrolyte, 650 mM (or 0.65 M) to the saturation limit of tin and / or tin-containing compounds in the electrolyte, 670 mM (or 0.67 M) to the saturation limit of tin and / or tin-containing compounds in the electrolyte, 750 mM (or 0.75 M) to the saturation limit of tin and / or tin-containing compounds in the electrolyte, below the saturation limit of tin and / or tin-containing compounds in the electrolyte, at the saturation limit of tin and / or tin-containing compounds in the electrolyte, etc.As a further example, tin and / or tin-containing compounds can be added to the electrolyte in an amount such that the added tin and / or tin-containing compounds are equal to about 0.01 wt % to about 20 wt % of the electrolyte. As a specific example, tin and / or tin-containing compounds can be present in the electrolyte at 0.01 wt %, 0.01 wt % to 0.1 wt %, 0.1 wt %, 0.01 wt % to 5 wt %, 0.1 wt % to 5 wt %, 0.1 wt % to 20 wt %, 5 wt %, 5 wt % to 20 wt %, 20 wt %, etc.

[0149] In various embodiments, tin and / or tin-containing compounds may be included as part of an anode in an electrochemical battery. For example, tin and / or tin-containing compounds may be incorporated into the anode, such as by mixing with an iron source of the anode, depositing on the anode surface, incorporating into an anode bed, etc. As an example, tin and / or tin-containing compounds may be added to the anode in an amount such that the added tin and / or tin-containing compounds are equal to about 0.1 wt % to about 40 wt % of the anode based on the dry mass of the anode (without electrolyte included in the wt % figure). As a specific example, tin and / or tin-containing compounds can be present in the anode in the following amounts: 0.1 wt%, 0.1 wt% to 6 wt%, 0.1 wt% to 1 wt%, about 1 wt%, about 1 wt% to about 3 wt%, about 3 wt%, about 3 wt% to about 6 wt%, about 1 wt% to about 6 wt%, about 6 wt%, 6 wt% to 20 wt%, 0.1 wt% to 5 wt%, 0.1 wt% to 0.5 wt%, about 0.5 wt%, 0.5 wt% to 5 wt%, about 5 wt%, 5 wt% to 6 wt%, 5 wt % to 7 wt %, 6 wt % to 7 wt %, about 7 wt %, about 1 wt % to about 20 wt %, 20 wt %, about 20 wt %, about 7 wt % to about 20 wt %, about 20 wt % to about 35 wt %, about 35 wt %, about 1 wt % to about 35 wt %, about 7 wt % to about 35 wt %, 35 wt %, about 1 wt % to about 40 wt %, about 7 wt % to about 40 wt %, about 20 wt % to about 40 wt %, about 35 wt % to about 40 wt %, about 40 wt %, 40 wt %, and the like. Additionally, tin and / or tin-containing compounds may be added to the anode in an amount such that the resulting tin incorporated into the anode is from about 0.044 wt % tin to about 20 wt % tin relative to the weight of the active material of the anode (e.g., relative to the weight of the active iron material of the anode), such as from about 0.044 wt % tin, 0.044 wt % tin to 0.1 wt % tin, about 0.1 wt % tin, 0.1 wt % tin to 6 wt % tin, 0.1 wt % tin to 1 wt % tin, about 1 wt % tin to about 3 wt % tin. wt % tin, about 3 wt % tin, about 3 wt % tin to about 6 wt % tin, about 1 wt % tin to about 6 wt % tin, about 6 wt % tin, 6 wt % tin to 20 wt % tin, 0.1 wt % tin to 5 wt % tin, about 5 wt % tin, 5 wt % tin to 6 wt % tin, 5 wt % tin to 7 wt % tin, 6 wt % tin to 7 wt % tin, about 7 wt % tin, 6 wt % tin to 10 wt % tin, about 10 wt % tin, 10 wt % tin to 20 wt % tin, about 20 wt % tin, and the like.

[0150] In various embodiments, stannates, such as sodium stannate trihydrate (Na2SnO3·3H2O), potassium stannate trihydrate (K2SnO3·3H2O), etc., can be added to or present in the electrochemical cell. In various embodiments, stannates, such as sodium stannate trihydrate (Na2SnO3·3H2O), potassium stannate trihydrate (K2SnO3·3H2O), etc., can be added to or present in the Fe anode or electrolyte of the electrochemical cell such as a battery in an amount of about 0.1 wt % to about 35 wt %. As an example, stannates, such as sodium stannate trihydrate (Na2SnO3·3H2O), potassium stannate trihydrate (K2SnO3·3H2O), etc., can be added to or present in an Fe anode or electrolyte of an electrochemical cell such as a battery in an amount of about 0.1 wt%, about 0.1 wt% to about 15 wt%, about 15 wt%, about 15 wt% to about 20 wt%, about 20 wt%, about 20 wt% to about 35 wt%, about 35 wt%, etc.

[0151] In one experiment, 0.1M sodium stannate (Na2SnO3·3H2O) was dissolved in a 6M potassium hydroxide-based electrolyte to provide a tin source for incorporation into the anode. Specifically, after the sodium stannate was dissolved, the composition of the electrolyte to which the sodium stannate was added was 5.95M KOH, 0.05M LiOH, 0.007M Na2S, 0.1M Na2SnO3·3H2O, and the experiment showed that tin was incorporated, absorbed or found in the anode. Throughout the cycling process (20+ cycles), the battery exhibited increased total capacity, step 1 capacity, and increased voltaic efficiency, resulting in longer round-trip efficiency. In various embodiments, when the electrolyte composition is adjusted, such as by using NaOH as part of the electrolyte in addition to or instead of KOH, a molar concentration similar to the molar concentration produced by the weight percentage addition listed in the potassium hydroxide-based electrolyte can be used to achieve similar performance levels. Other experiments have demonstrated that when a sulfide may be included in the anode or electrochemical cell, a sulfide such as Na2S may not need to be included in the electrolyte. In such experiments, the composition of the electrolyte to which the sodium stannate was added after it was dissolved and before contact with the anode or other electrode was 5.95 M KOH, 0.05 M LiOH, and 0.04 M Na2SnO3.3H2O.

[0152] In another experiment, 5 wt% sodium stannate (Na2SnO3·3H2O) (equivalent to 2.22 wt% Sn to active iron material) was mixed with the iron source of the anode before testing. Specifically, after dissolving the sodium stannate, the composition of the electrolyte to which the sodium stannate was added was 5.95M KOH, 0.05M LiOH, 0.01M Na2S, 5 wt% Na2SnO3·3H2O, and the experiment showed that in addition to increasing the total capacity and step 1 capacity, tin was also incorporated into the anode.

[0153] In some embodiments, tin oxide (SnO2) can be dissolved in the electrolyte at a concentration of 0.01 wt% to 20 wt%. In some aspects, the SnO2 source can be a cassiterite ore. In some aspects, relative to mined cassiterite ore, the SnO2 source can be a refined and / or purified SnO2 material.

[0154] In some embodiments, cylindrical cassiterite (Pb3Sn4FeSb2S 14 ) is added to the electrolyte and / or the electrode.

[0155] In some embodiments, copper iron tin sulfide (Cu2FeSnS 4 ) is added to the electrolyte and / or the electrode.

[0156] In some embodiments, metallic tin may be added to the electrolyte and / or the electrodes.

[0157] In some embodiments, tin sulfide (SnS or SnS2) may be added to the electrolyte and / or the electrode.

[0158] In certain embodiments where the tin and / or tin-containing compound is a solid, the specific surface area (m 2 / g, as measured by the Brunauer-Emmett-Teller method of gas adsorption), to provide a specified reactivity level such that there is a constant flux of tin into the liquid phase, or to maintain the tin concentration in the liquid electrolyte phase at or above a certain critical concentration.

[0159] In some embodiments, the electrolyte used with the iron negative electrode may include tin-containing ions. The specific type of tin-containing ions may vary based on the pH and potential of the solution. In alkaline electrolytes, the tin ions may be SnO3 2- or Sn(OH)6 2- In some embodiments, the concentration of the tin-containing ions may be selected such that the dissolved tin in the solution is equal to 0.01 wt % to 35 wt % of the active material iron in the negative electrode.

[0160] In various embodiments, tin and / or tin-containing compounds can be included in the electrochemical cell in any suitable manner so that the tin is incorporated into the iron anode. As an example, the tin and / or tin-containing compounds can be supplied to the electrochemical cell in any of the various ways discussed for placing additives in the electrochemical cell.

[0161] In some embodiments, tin and / or tin-containing compounds can be deposited on the anode and / or cathode of the electrochemical cell, for example, by electroless deposition. In some embodiments, a tin reservoir can be provided in the electrochemical cell. The tin reservoir can allow more tin than the solubility limit allows to be added to the electrochemical cell. In some embodiments, the tin reservoir can be electrically connected to a source of oxidation potential to promote tin to dissolve due to the formation of tin-containing soluble ion species. In some embodiments, tin and / or tin-containing compounds can enter the electrolyte supersaturatedly. In some embodiments, tin and / or tin-containing compounds can be arranged in the electrolyte as foil, rod or other size specifications, and can be dissolved into the electrolyte over time. In certain embodiments, the electrode maintained in a more positive (more anode) potential can initially be tinned. As a non-limiting example, in an iron-air battery pack, the air cathode can initially be tinned so that the tin species (species) are electrically driven to leave the cathode and enter the solution. In certain embodiments, the air electrode can be an oxygen evolution reaction (OER) electrode. The tin (or tin-containing) coating can be applied, for example, by "hot dipping" or other processes known to those skilled in the art. When the tin-coated electrode is initially polarized to the anode potential while in contact with an alkaline electrolyte, the tin species can be electrochemically dissolved into the solution and form stannates in the electrolyte. In multiple embodiments, the tin coating can be applied to any part of the oxidized surface. In some embodiments, there may be a bulk or other shaped structure of tin electrically and mechanically connected to the OER electrode and / or oxygen reduction reaction (ORR) electrode, and the bulk or other shaped structure of tin may be corroded away, thereby adding tin to the electrolyte. In some embodiments, the tin wire or tin rod may be mechanically isolated from the second electrode during charging but electrically short-circuited so that the tin is dissolved in the electrochemical cell. In some embodiments, the tin wire or tin rod may be mechanically and electrically connected to the second electrode during charging so that the tin is dissolved in the electrochemical cell. In some embodiments, the tin wire or tin rod may be mechanically and electrically isolated from all electrodes and allowed to dissolve into the electrolyte over time.

[0162] In various embodiments, tin and / or tin-containing compounds can be added to the electrochemical cell while the electrochemical cell is in operation. For example, tin and / or tin-containing compound inserts can be replaced in the electrochemical cell, additional tin and / or tin-containing compounds can be pumped into and / or otherwise added to the electrochemical cell, and / or tin and / or tin-containing compounds can be added in other ways to maintain a selected molar amount and / or weight percent of tin and / or tin-containing compounds in the electrolyte and / or electrode.

[0163] In various embodiments, antimony (Sb) and / or antimony-containing compounds can be included (e.g., added, present, etc.) in an electrochemical cell, such as in an electrolyte, as part of an electrode, as a reservoir in an electrochemical cell, etc. Antimony and / or antimony-containing compounds can replace or be combined with the above-described tin and / or tin-containing compounds, and can operate in a similar manner to coat an iron anode and reduce or terminate the HER reaction to help improve charging / recharging of an electrochemical cell. Figure 3 is the Pourbaix diagram of antimony. As a specific example, antimony dialkyl dithiophosphate (SbC 18 H 42 O6P3S6), antimony selenide (Sb2Se3), antimony (III) oxide (Sb2O3), antimony (V) oxide (Sb2O5), metallic antimony, antimony acetate (SbC6H9O6), antimony potassium tartrate (Sb2K2C8H4O 12 ), sodium antimony tartrate (Sb2Na2C8H4O 12 ), antimony sulfate (Sb2(SO4)3), antimony (III) sulfide (Sb2S3), potassium antimonate trihydrate (KSb2O3·3H2O), or mixtures thereof may be included in an electrochemical cell, for example in an electrolyte and / or an electrode.

[0164] In various embodiments, antimony (Sb) and / or antimony-containing compounds may be included as part of an electrolyte in an electrochemical cell. As an example, antimony (Sb) and / or antimony-containing compounds may be added to the electrolyte in an amount such that the amount of antimony (Sb) and / or antimony-containing compounds added is equal to about 0.1 millimolar (mM) to about the saturation limit of the antimony (Sb) and / or antimony-containing compounds in the electrolyte.As a specific example, antimony (Sb) and / or antimony-containing compounds may be present in the electrolyte at the following concentrations: 0.1 mM, 0.1 mM to 10 mM, 0.1 mM to 100 mM (or 0.1 M), 10 mM, 10 mM to 100 mM (or 0.1 M), 10 mM to 50 mM, 50 mM, 50 mM to 60 mM, 10 mM to 70 mM, 10 mM to 60 mM, 50 mM to 100 mM (or 0.1 M), 50 mM to 70 mM, 60 mM to 70 mM, 60 mM, 70 mM, 70 mM to 100 mM (or 0.1 M), 10 mM to 80 mM, 50 mM to 80 mM, 60 mM to 80 mM , 70mM to 80mM, 80mM, 80mM to 100mM (or 0.1M), 100mM (or 0.1M), 100mM (or 0.1M) to 1M, 1M, 100mM (or 0.1M) to 750mM (or .75M), 750mM (or .75M), 100mM (or 0.1M) to 500mM (or .5M), 500mM (or .5M), 100mM (or 0.1M) to 600mM (or .6M), 600mM (or .6M), 100mM (or 0.1M) to 670mM (or .67M), 670mM (or .67M), 500mM (or 0.5M) to 670 mM (or .67M), 600mM (or 0.6M) to 670mM (or .67M), 650mM (or 0.65M) to 670mM (or .67M), 650mM (or .65M), 0.1mM to the saturation limit of antimony (Sb) and / or antimony-containing compounds in the electrolyte, 10mM to the saturation limit of antimony (Sb) and / or antimony-containing compounds in the electrolyte, 50mM to the saturation limit of antimony (Sb) and / or antimony-containing compounds in the electrolyte, 100mM (or 0.1M) to the saturation limit of antimony (Sb) and / or antimony-containing compounds in the electrolyte, 500mM (or 0.5M) to the saturation limit of antimony (Sb) and / or antimony-containing compounds in the electrolyte, 6 00mM (or 0.6M) to the saturation limit of antimony (Sb) and / or antimony-containing compounds in the electrolyte, 650mM (or 0.65M) to the saturation limit of antimony (Sb) and / or antimony-containing compounds in the electrolyte, 650mM (or 0.65M) to the saturation limit of antimony (Sb) and / or antimony-containing compounds in the electrolyte, 670mM (or 0.67M) to the saturation limit of antimony (Sb) and / or antimony-containing compounds in the electrolyte, 750mM (or 0.75M) to the saturation limit of antimony (Sb) and / or antimony-containing compounds in the electrolyte, below the saturation limit of antimony (Sb) and / or antimony-containing compounds in the electrolyte, at the saturation limit of antimony (Sb) and / or antimony-containing compounds in the electrolyte, etc.As a further example, antimony (Sb) and / or an antimony-containing compound may be added to the electrolyte in an amount such that the added antimony (Sb) and / or antimony-containing compound is equal to about 0.01 wt % to about 20 wt % of the electrolyte. As a specific example, antimony (Sb) and / or an antimony-containing compound may be present in the electrolyte at 0.01 wt %, 0.01 wt % to 0.1 wt %, 0.1 wt %, 0.01 wt % to 5 wt %, 0.1 wt % to 5 wt %, 0.1 wt % to 20 wt %, 5 wt %, 5 wt % to 20 wt %, 20 wt %, etc.

[0165] In various embodiments, antimony (Sb) and / or antimony-containing compounds may be included as part of the anode in an electrochemical battery. For example, antimony (Sb) and / or antimony-containing compounds may be incorporated into the anode, such as mixed with an iron source of the anode, deposited on the anode surface, incorporated into the anode bed, etc. As an example, antimony (Sb) and / or antimony-containing compounds may be added to the anode in an amount such that the antimony (Sb) and / or antimony-containing compounds added are equal to about 0.1 wt % to about 40 wt % of the anode based on the dry mass of the anode (without electrolyte included in the wt % figure). As a specific example, antimony (Sb) and / or an antimony-containing compound can be present in the anode in the following amounts: 0.1 wt %, 0.1 wt % to 6 wt %, 0.1 wt % to 1 wt %, about 1 wt %, about 1 wt % to about 3 wt %, about 3 wt %, about 3 wt % to about 6 wt %, about 1 wt % to about 6 wt %, about 6 wt %, 6 wt % to 20 wt %, 0.1 wt % to 5 wt %, 0.1 wt % to 0.5 wt %, about 0.5 wt %, 0.5 wt % to 5 wt %, about 5 wt %, 5 wt % to 6 wt %. %, 5 to 7 weight %, 6 to 7 weight %, about 7 weight %, about 1 to about 20 weight %, 20 weight %, about 20 weight %, about 7 weight % to about 20 weight %, about 20 weight % to about 35 weight %, about 35 weight %, about 1 to about 35 weight %, about 7 weight % to about 35 weight %, 35 weight %, about 1 to about 40 weight %, about 7 weight % to about 40 weight %, about 20 weight % to about 40 weight %, about 35 weight % to about 40 weight %, about 40 weight %, 40 weight %, and the like.

[0166] In one experiment, 0.1M antimony acetate (Sb(C2H3O)2) was dissolved in a 6M potassium hydroxide-based electrolyte to provide an antimony source for incorporation into the anode. Specifically, after dissolving the antimony acetate, the composition of the electrolyte was 5.95M KOH, 0.05M LiOH, and 0.1M Sb(C2H3O)2. Throughout the cycling process (50+ cycles), the cell exhibited increased total capacity, step 1 capacity, and increased coulombic efficiency, resulting in longer round-trip efficiency.

[0167] In another experiment, 0.005M sodium antimony tartrate (Na2Sb2(C4H2O6)2) was dissolved in a 6M potassium hydroxide-based electrolyte to provide an antimony source for incorporation into the anode. Specifically, after dissolving the sodium antimony tartrate, the composition of the electrolyte was 5.95M KOH, 0.05M LiOH, and 0.005M Na2Sb2(C4H2O6)2. Throughout the cycling process (50+ cycles), the cell exhibited increased total capacity, step 1 capacity, and increased coulombic efficiency, resulting in longer round-trip efficiency.

[0168] In various embodiments, indium (In) and / or indium-containing compounds can be included (e.g., added, present, etc.) in an electrochemical cell, such as in an electrolyte, as part of an electrode, as a reservoir in an electrochemical cell, etc. Indium and / or indium-containing compounds can replace or be combined with tin and / or tin-containing compounds and / or antimony and / or antimony-containing compounds discussed above, and can operate in a similar manner to coat an iron anode and reduce or terminate the HER reaction to help improve charging / charging of an electrochemical cell. As specific examples, metallic indium (In), indium (III) chloride (InCl3), indium (III) hydroxide (In(OH)3), indium (III) oxide (In2O3), indium (III) sulfate (In2(SO4)3), indium (III) sulfide (In2S3), indium phosphide (InP), indium (III) acetate (In(C3H3O2)3), indium (III) nitrate (In(NO3)3), indium (III) sulfide (In2S3), indium (III) selenide (In2Se3), indium nitride (In Indium (III) bromide (InBr3), indium (I) oxide (In2O), indium (II) oxide (InO), indium (II) selenide (InSe), indium (I) bromide (InBr), indium antimonide (InSb), or mixtures thereof, may be included in an electrochemical cell, for example, in an electrolyte and / or an electrode. In various embodiments, the tin source may be a solid tin source or a soluble tin source. Figure 2A-2C It is Pulbaitu of Tin.

[0169] In various embodiments, indium and / or indium-containing compounds may be included as part of an electrolyte in an electrochemical cell. As an example, indium and / or indium-containing compounds may be added to an electrolyte in an amount such that the added indium and / or indium-containing compounds are equal to about 0.1 millimoles (mM) to about the saturation limit of the indium and / or indium-containing compounds in the electrolyte. As a specific example, indium and / or indium-containing compounds may be present in the electrolyte at the following concentrations: 0.1 mM, 0.1 mM to 10 mM, 0.1 mM, 10 mM, 0.1 mM to 1 mM, 1 mM, 1 mM to 5 mM, 5 mM, 5 mM to 10 mM, 0.1 mM to the saturation limit of indium and / or indium-containing compounds in the electrolyte, 1 mM to the saturation limit of indium and / or indium-containing compounds in the electrolyte, 5 mM to the saturation limit of indium and / or indium-containing compounds in the electrolyte, below the saturation limit of indium and / or indium-containing compounds in the electrolyte, etc. As a further example, indium and / or an indium-containing compound can be added to the electrolyte in an amount such that the added indium and / or indium-containing compound is equal to about 0.01 wt % to about 20 wt % of the electrolyte. As a specific example, indium and / or an indium-containing compound can be present in the electrolyte in an amount of 0.01 wt %, 0.01 wt % to 0.1 wt %, 0.1 wt %, 0.01 wt % to 5 wt %, 0.1 wt % to 5 wt %, 0.1 wt % to 20 wt %, 5 wt %, 5 wt % to 20 wt %, 20 wt %, etc.

[0170] In various embodiments, indium and / or indium-containing compounds may be included as part of an anode in an electrochemical battery. For example, indium and / or indium-containing compounds may be incorporated into the anode, such as by mixing with an iron source of the anode, depositing on the anode surface, incorporating into an anode bed, etc. As an example, indium and / or indium-containing compounds may be added to the anode in an amount such that the added indium and / or indium-containing compounds equals about 0.1 wt % to about 15 wt % of the anode based on the dry mass of the anode (without electrolyte included in the wt % figure). As a specific example, indium and / or an indium-containing compound can be present in the anode at 0.1 wt%, 0.1 wt% to 6 wt%, 0.1 wt% to 1 wt%, about 1 wt%, about 1 wt% to about 3 wt%, about 3 wt% to about 6 wt%, about 1 wt% to about 6 wt%, about 6 wt%, 6 wt% to 10 wt%, 0.1 wt% to 5 wt%, 0.1 wt% to 0.5 wt%, about 0.5 wt%, 0.5 wt% to 5 wt%, about 5 wt%, 5 wt% to 6 wt%, 5 wt% to 7 wt%, 6 wt% to 7 wt%, about 7 wt%, about 1 wt% to about 15 wt%, 15 wt%, about 15 wt%, about 7 wt% to about 15 wt%, about 7 wt% to about 10 wt%, about 7 wt%, about 10 wt%, about 10 wt% to about 12 wt%, about 12 wt%, about 12 wt% to about 15 wt%, and the like.

[0171] Multiple embodiments include using tin-containing compounds, antimony-containing compounds, and / or indium-containing compounds as additives to electrolytes and / or electrodes in electrochemical systems (such as batteries) with iron-based anodes. In multiple embodiments, the addition of stannates, antimony, and / or indium can increase the total capacity, step 1 capacity, coulombic efficiency, voltaic efficiency, and cycle of the iron-based anode. In multiple embodiments, stannates, antimony, and / or indium are added as additives to the electrolyte and / or electrodes of electrochemical systems (such as batteries) with iron-based anodes, and the discharge capacity of the iron-based anode can be greater than 200mAh / g, for example, 200mAh / g to 300mAh / g, greater than 300mAh / g, 300mAh / g to 350mAh / g, 350mAh / g, 350mAh / g to 400mAh / g, 400mAh / g, greater than 400mAh / g, etc. In various embodiments, stannate, antimony and / or indium are added as additives to the electrolyte and / or electrode of an electrochemical system (such as a battery) having an iron-based anode, and the discharge potential of the iron-based anode can be greater than 0.70V, such as 0.70V to 0.75V, 0.75V, greater than 0.75V, 0.75V to 0.8V, 0.8V, greater than 0.8V, 0.8V to 0.85V, 0.85V, greater than 0.85V, 0.85V to 0.9V, 0.9V, greater than 0.9V, etc. Various embodiments can provide an iron-based anode with a highly reversible step 1 reaction. Various embodiments can provide an iron-based anode with a highly reversible step 1 reaction in the presence of stannate, antimony and / or indium.

[0172] Various embodiments may include an electrochemical cell comprising an iron anode having a high hydroxide concentration electrolyte, such as a hydroxide concentration equal to or greater than about 6M (e.g., about 6M, 6M, about 6M or greater, about 6M to about 7M, 6M to 7M, about 6.5M, 6.5M, about 6M to about 6.5M, 6.5M to about 7M, about 7M or greater, about 7M to about 11M, about 7M to about 10M, about 6M to about 7.5M, about 6.5M to about 7.5M, about 7M to about 7.5M, about 7.5M, about 7.5M to about 9.5M, greater than 6M to less than 9.5M, greater than 6.5M to less than 9.5M, greater than 7M to less than 9.5M, greater than 7.5M to less than 9.5M, etc.). The high hydroxide concentration electrolyte may enable a better step 1 reaction, i.e. For iron electrode electrochemical cells, such as iron anode batteries, various embodiments can include a high concentration alkaline electrolyte comprising a high hydroxide concentration, for example a hydroxide concentration equal to or greater than about 6 M (e.g., about 6 M, 6 M, about 6 M or greater, about 6 M to about 7 M, 6 M to 7 M, about 6.5 M, about 6.5 M or greater, about 6 M to about 6.5 M, 6.5 M, 6 M to 6.5 M, about 6.5 M to about 7 M, 6.5 M to 7 M, about 7 M or greater, about 7 M, about 7 M to about 7.5 M, about 7.5 M, about 6 M to about 7.5 M, about 6.5 M to about 7.5 M, 7.5 M, about 7 M to about 11 M, about 7 M to about 10 M, about 7.5 M to about 9.5 M, greater than 7.5 M to less than 9.5 M, etc.). In various embodiments, the hydroxide in the electrolyte may include any one or more of KOH, NaOH, LiOH, RbOH, CsOH, FrOH, Be(OH)2, Ca(OH)2, Mg(OH)2, Sr(OH)2, Ra(OH)2, Ba(OH)2, and mixtures thereof. In various embodiments, KOH, NaOH, and LiOH are combined in a ratio such that [KOH]>[NaOH]>[LiOH]. Various embodiments may include about 4M KOH, 2M NaOH, 0.05M LiOH, or other combinations thereof. In various embodiments, KOH, NaOH, and LiOH are combined in a ratio such that [NaOH]>[KOH]>[LiOH]. Various embodiments may include about 4M NaOH, 2M NaOH, 0.05M LiOH, or other combinations thereof.

[0173] Conventionally, iron-based batteries operate for no more than about sixteen hours, with a duration of four to twelve hours being more typical. In other words, conventionally, iron-based batteries operate for no more than about sixteen hours in discharge mode, with a duration of four to twelve hours being more typical for the duration of the discharge mode. Therefore, conventionally, iron-based batteries are tested with a relatively high discharge rate, for example, for 1 to 8 hours to discharge the full capacity of a conventional iron-based battery. These shorter conventional discharge times and relatively high discharge rates for conventional testing make it possible for longer discharge times (e.g., longer than 24 hours, 24 hours to 30 hours, more than 30 hours, 30 hours to 100 hours, more than 100 hours, 100 hours to 150 hours, more than 150 hours, etc.) to have an effect on iron-based electrochemical cells that has not been studied. Specifically, the effects of high hydroxide electrolytes (e.g., hydroxide electrolytes having about 6 M or more hydroxide in the electrolyte) on iron-based electrochemical cells having longer discharge times (e.g., longer than 24 hours, 24 hours to 30 hours, greater than 30 hours, 30 hours to 100 hours, greater than 100 hours, 100 hours to 150 hours, greater than 150 hours, etc.) have not been previously studied.

[0174] The inventors have experimentally discovered that certain anode materials at hydroxide concentrations less than about 6M result in worse performance than those anode materials at higher hydroxide concentrations (e.g., about 6M, 6M, or greater than 6M hydroxide concentrations). The inventors have specifically discovered that when using lower purity (and therefore lower cost) materials and cycling at lower rates, the effect of hydroxide content on performance is much stronger than expected in the prior art. Therefore, in the commercial context of long-term, ultra-low-cost grid-scale energy storage, high hydroxide content has unique and unexpected advantages for battery performance, and not only helps to increase the amount of charge storage stored in the battery (i.e., the capacity of the battery material), but also can effectively reduce the overpotential of the battery (i.e., increase the voltage). High hydroxide concentrations, such as hydroxide concentrations equal to or greater than about 6M, are not intuitively pursued because they result in an electrolyte with lower conductivity, higher viscosity, and higher cost than a low hydroxide electrolyte. The inventors have found that the hydroxide content has a very strong effect on the battery capacity at a duration longer than 24-30 hours, and the preferred hydroxide concentration in the electrolyte is greater than 7M. Hydroxide concentrations up to about 11 M have been tested, with enhanced performance even at these very high concentrations. The upper limit of hydroxide concentration is the solubility limit, e.g. Figure 5 The solubility limit depends on temperature, and the electrochemical cell, such as a battery, may be insulated and / or otherwise heated to obtain a higher operating temperature and, therefore, a higher hydroxide solubility. In some embodiments, when side reactions in the electrolyte result in a net loss of hydroxide, it may be beneficial to exceed the solubility limit to obtain an excess supply of solid hydroxide in order to maintain the highest possible concentration of hydroxide. In various embodiments, hydroxide replenishment may also be achieved by quantitatively adding a hydroxide salt to the electrolyte over the life of the battery.

[0175] In some embodiments, the electrolyte may have a total hydroxide concentration greater than 7M, including KOH+NaOH greater than 6M and LiOH greater than 0.05. In some embodiments, the electrolyte may have a total hydroxide concentration less than or equal to 11M. In some embodiments, the electrolyte may have a total hydroxide concentration less than or equal to 11M, including LiOH less than or equal to 1M and KOH less than or equal to 10M. In some embodiments, when the electrolyte is based on KOH, the total hydroxide concentration may be greater than 7M and less than 10M. In some embodiments, when the electrolyte is based on KOH, the total hydroxide concentration may be greater than 7.5M and less than 9.5M.

[0176] In some embodiments, sulfide may be included in the electrolyte as an additional additive, and the sulfide concentration is 0.001M to 0.5M, typically sodium sulfide. In some embodiments, sulfide may be included in the electrolyte as an additional additive, and the sulfide concentration is 0.00001M to 0.5M, typically sodium sulfide. Sulfide can be added to the electrolyte using other salts, such as potassium sulfide. In some embodiments, additional sulfide may not be added to the electrolyte. For example, sulfide may not be present in the electrolyte. In some embodiments, sulfide may be present in other aspects of the electrochemical cell, such as in the form of an anode additive. As an example, when sulfide is not present in the electrolyte, sulfide or a sulfide-containing compound may be an additive to the anode. In multiple embodiments, other electrolyte additives known in the art for enhancing performance or iron electrodes may also be used in the electrolyte. In multiple embodiments, the solvent in the electrolyte may generally be water, and preferably high-purity water, such as deionized water.

[0177] Figure 4 A graph showing experimental results for different DRI types using different hydroxide concentrations according to various embodiments. By cycling the anode half-cells with different concentrations of hydroxide electrolyte, it was found that the relative purity of the DRIs between various lower purity iron materials (in Figure 4 The diagram is represented as "DRI type", specifically, Figure 4 In the example of the four different lower purity iron materials labeled "1", "2", "3" and "4" in the Figure 1, 6M hydroxide in the electrolyte resulted in worse performance than higher concentrations of hydroxide (e.g., 7M or higher). More specifically, it was found that increasing the hydroxide content of the electrolyte resulted in an increase in capacity achieved by the following iron oxidation reaction, namely step 1 reaction By increasing the capacity achieved by the step 1 reaction, not only does this increase the total energy stored in the battery pack, it also increases the cell's voltaic efficiency, resulting in an overall higher round-trip efficiency.

[0178] Various embodiments include using high hydroxide concentration electrolytes, such as 7 molar (M) hydroxide concentrations or higher, in electrochemical systems such as batteries. In various embodiments, high hydroxide concentration electrolytes, such as 7M hydroxide concentrations or higher, can increase the amount of charge stored in the battery (i.e., the capacity of the battery material), improve Coulombic efficiency (i.e., increase the amount of electrons stored in the intended charge products rather than being wasted in side reactions), and / or reduce the overpotential of the battery (i.e., increase the voltage).

[0179] In various embodiments, the alkyl polyglucosides can be used as co-additives to metal HER inhibitors.

[0180] A variety of additives are used in battery packs to optimize performance for multiple metrics, including available capacity and coulombic efficiency, among others. Certain types of additives that are good HER inhibitors may also be electrochemically active in the same or similar potential window as the target electrode (e.g., metal HER inhibitors or conductive additives). Because these additives can be reversibly deposited on the electrode, the electrode microstructure changes over time and may form dendrites or passivation films that can short-circuit the battery or cause other failures.

[0181] In various embodiments, organic additives, such as a class of compounds known as alkyl polyglucosides (APGs), can be used to control the chemical or electrochemical deposition of metal ions to prevent the formation of dendrites or to create and maintain specific structures on the surface of the electrode. APG is an organic surfactant derived from glucose and fatty alcohols. The alcohol functional groups of APG can increase solubility in aqueous solutions. APG molecules are believed to adsorb on the iron surface and limit the deposition rate of the additive on the surface, thereby promoting the formation of uniform, controlled deposits on the surface. In some embodiments, organic additives including but not limited to APGs may be included in the electrolyte as additional additives. In some embodiments, the organic additives may be included in the electrolyte after the first charge (i.e., "added to the battery in a specified amount"). In some embodiments, the organic additives may include other surfactant chemicals, including but not limited to linear alkylbenzene sulfonates, lignin sulfonates, fatty alcohol ethoxylates and / or alkylphenol ethoxylates.

[0182] Various embodiments may include incorporating tin into the current collector.

[0183] Additives that slow hydrogen evolution or reduce HER activity on the iron electrode can be used to improve the efficiency of iron oxide reduction. These additives can be incorporated in a variety of ways and different size specifications to maximize the interaction and effect with the target electrode. In various embodiments, additives that reduce HER activity can be incorporated into the current collector.

[0184] Multiple embodiments may include incorporating tin or other metals / species into the current collector. In multiple embodiments, the metal / species incorporated into the current collector may be a HER inhibiting metal / substance or a metal / species that reduces HER activity. In some embodiments, metals / species including but not limited to tin are plated on the current collector. In some embodiments, metals / species including but not limited to tin are plated on the current collector with a layer of thickness sufficient to provide tin or other HER inhibiting species in an amount equal to or less than 0.1M when dissolved in the electrolyte. In some embodiments, metals / species including but not limited to tin are coated on one or both sides of the current collector in contact with the anode by hot-dip tinning. In some embodiments, metals / species including but not limited to tin are electroplated on the current collector. In some embodiments, the current collector is stainless steel, carbon steel, or nickel. In some embodiments, a mixture of metals / species including but not limited to tin and lead is used.

[0185] Various embodiments may include doping the sponge iron with tin.

[0186] Tin can be a performance-enhancing additive in electrochemical energy storage systems using iron anodes. More uniform incorporation of tin-containing additives is expected to improve the performance of iron electrodes. Low-cost sponge iron-based materials may not be incorporated with tin at the time of production, which may limit the performance of these materials due to uneven incorporation. Similarly, sulfide additives, including Na2S, FeS, SnS, SnS2, MnS, and ZnS, have been shown to enhance the performance of iron anodes. It can be difficult to uniformly incorporate any solid-state additive into a sponge iron precursor, especially in a cost-effective manner.

[0187] In various embodiments, the desired additives may be incorporated into the powder mixture used to produce the sponge iron prior to reducing the sponge iron. In various embodiments, the additives may be incorporated in a manner to ensure that they reach the final product in a desired state (rather than evaporating away or changing state in a manner that would irreversibly cause the additive to lose its function).

[0188] In some embodiments, cassiterite concentrate or some other tin oxide (e.g., SnO2) source may be incorporated into the iron concentrate used to make direct reduced iron (DRI) so that it does not evaporate during the firing step and then co-reduced with the iron oxide after the reduction process is complete to produce a tin-containing sponge. In some embodiments, sodium sulfide, zinc sulfide, or manganese sulfide is added to the iron oxide powder and reduced to form an iron oxide sponge containing sodium sulfide, zinc sulfide, or manganese sulfide. In some embodiments, a solid-state additive (e.g., cylindrical cassiterite (PbSn4FeSb2S 14 )) is incorporated into the iron concentrate. In some embodiments, tin or other desired solid additives are incorporated into the iron concentrate before reduction.

[0189] In various embodiments, if the solid additive is soluble in the electrolyte, the solid additive may also be a pore former to increase the porosity of the iron electrode. In one example, a tin-based additive may be provided that dissolves in the electrolyte of the iron anode. In this case, the additive performs multiple design functions simultaneously.

[0190] Various embodiments may include a hydrogen oxidation catalyst and / or a hydrogen getter as an additive to the anode of an electrochemical cell.

[0191] During the operation of an electrochemical energy storage (ESS), the electrodes of the ESS participate in electrochemical reduction and oxidation reactions. Hydrogen is a possible product of the ESS reduction reaction from the protic electrolyte or aqueous electrolyte produced at the negative electrode (negode). In some embodiments, it may be desirable to precipitate hydrogen by electrolysis of the electrolyte (e.g., in a flow battery in which the anode electrolyte contains a soluble hydrogenation product). However, in other embodiments, such as in a metal-air battery, the evolution of hydrogen (e.g., during charging of the metal negative electrode) may have adverse consequences for the operation and performance of the ESS.

[0192] The first undesirable consequence of hydrogen evolution at the metal anode during charging may be the formation of hydrogen gas bubbles. The formation of bubbles within the electrolyte may adversely affect the performance of the ESS by limiting the contact between the electrolyte and the anode surface. Limiting the contact between the electrolyte and the anode surface may have a chain reaction of negative reactions, such as limiting the rate performance of the ESS and causing uneven current distribution (hot spots) on the anode surface. The formation of hydrogen gas may lead to pressure accumulation, for example, in an ESS comprising a sealed compartment or a quasi-sealed compartment, which also includes a reducing metal anode (iron anode). In addition, the pressure accumulation may adversely affect the safety and operating conditions of the ESS by causing compartment leakage or becoming a fuel source for uncontrolled combustion or reduction side reactions within the ESS.

[0193] A second undesirable consequence of hydrogen evolution at the metal anode during charging may be the conversion of charge into parasitic byproducts that are useless for productive charging or discharging, such as reducing the efficiency of ESS.

[0194] Multiple embodiments can mitigate the adverse effects caused by hydrogen evolution. In some embodiments, the adverse effects caused by hydrogen evolution can be mitigated by including a molecular hydrogen getter for capturing hydrogen in a soluble or quasi-soluble form. The getter can be a degasser, an absorbent, or a scavenger. Examples of reversible getters include zirconium, magnesium-nickel alloys; AB5 lanthanide-nickel alloys, graphite materials (graphite, graphene, low-dimensional carbon materials); phenyl propargyl ether; diphenyl propargyl ether. In addition, an irreversible getter can be combined with or replace a reversible getter in multiple embodiments. In multiple embodiments, the getter can be a surface in contact with the electrolyte. In multiple embodiments, the getter can be a filler material mixed into the anode composite. In multiple embodiments, the getter can be a molecular component of the electrolyte. The purpose of the getter can be to isolate H2-against bubbles (mechanical / surface barrier effect), isolate H2 to prevent it from being consumed as fuel in combustion reactions or side reactions, and capture hydrogen so that it can be consumed in the HOR, increasing the reversible capacity of the ESS.

[0195] In some embodiments, the adverse effects caused by hydrogen evolution can be mitigated by including a HOR catalyst. The purpose of the catalyst can be to consume hydrogen in a productive oxidation (HOR) upon discharge, increasing the reversible capacity of the ESS and improving the Coulombic efficiency (and, by extension, the round-trip energy efficiency of the ESS system).

[0196] Various embodiments may include lignin sulfonates for use as electrolyte additives and / or anion selective membranes.

[0197] The irreversible loss of sulfide in the iron anode during the cycling of the electrochemical cell or through calendar aging is one of the main reasons for the loss of available capacity of the iron anode over time. Sulfide can be added to the anode or electrolyte of an iron-based battery to activate the anode material. A certain amount of sulfide may be released when the iron is reduced during charging. After being released from the iron surface, the sulfide can migrate to the positive electrode and oxidize rapidly and irreversibly. In the absence of an applied potential, oxidation can still occur in the presence of an electrode with a sufficiently positive open circuit potential or an oxidant (such as oxygen). This oxidation causes oxidized sulfur species such as sulfate to accumulate in the electrolyte and at the positive electrode. In some electrolytes, sulfates can precipitate as alkaline sulfates, blocking the active area of ​​the electrode by blocking pores through chemical adsorption or physical adsorption, or physically blocking the diffusion path to the electrode surface through the accumulation of precipitates in the electrolyte.

[0198] In various embodiments, additives may be added to the anode or electrolyte to reduce the migration of sulfide to the positive electrode or to consume sulfide or sulfate released from the anode. In various embodiments, additionally or alternatively, an anion selective membrane or separator may be introduced between the negative electrode and the positive electrode to prevent (or further prevent) the migration of specific ions.

[0199] In various embodiments, lignin and its derivatives, such as lignin sulfonates, can be used as additives in electrolytes, as part of membranes, and / or as sulfide sinks in batteries containing iron anodes. In caustic solutions, lignin can react with sulfides and their oxidation byproducts to form lignin sulfonates, and can prevent sulfide from migrating to the positive electrode by reacting with sulfides before the sulfides reach the positive electrode. The resulting lignin sulfonates can then chelate impurities in the electrolyte, preventing potentially harmful chemicals or ions from interacting with either electrode. In various embodiments, lignin sulfonates can be incorporated into the system by electrical connection to the anode, in a permeable container adjacent to the anode and / or in the electrolyte.

[0200] In some embodiments, lignin, lignin sulfonate, or a mixture of the two can be added directly to the electrolyte solution (e.g., 5.95M KOH, 0.05M LiOH, 0.01M Na2S) in a range of 0.1% to 10% by volume before, immediately before, or during the cycle. In some embodiments, lignin sulfonate type additives, including but not limited to sodium lignin sulfonate, can be included in the electrolyte as an additional additive at a concentration of 0.1% to 10% by volume. In some embodiments, lignin sulfonate type can be included at a concentration of 0.1% to 1% by volume. In some embodiments, lignin sulfonate type additives can be included at a concentration of 1% to 10% by volume. In some embodiments, lignin sulfonate type additives can be included in the electrolyte after a period of time after the formation cycle (i.e., "added to the battery in a specified amount"). In some embodiments, lignin sulfonate type additives can be included in the electrolyte after the sulfide in the solution is determined to be below a certain threshold (e.g., <1.0E-3M or <1.0E-6M). In some embodiments, the lignin sulfonate-type additive may include other chemical species, including but not limited to other functionalized sulfonic acids.

[0201] In some embodiments, lignin, lignin sulfonate, or a mixture of the two can be added directly to the anode. In some embodiments, lignin sulfonate type additives, including but not limited to sodium lignin sulfonate, can be directly included in the anode as an additive. In some embodiments, lignin sulfonate type can be directly included in the anode as an additive. In some embodiments, lignin sulfonate type additives can be included in the anode as an additive. In some embodiments, lignin sulfonate type additives can be included in the anode before being assembled into an electrode. In some embodiments, lignin sulfonate type additives can be incorporated into the outside of the anode after formation.

[0202] In various embodiments, lignin, lignin sulfonate, or a mixture of both can be coated on a membrane placed in an electrochemical cell. Figure 7 Aspects of electrochemical cells including lignin sulfonate membranes according to multiple embodiments are shown. In some embodiments, lignin, lignin sulfonate, or a mixture of the two can be coated on a membrane (e.g., cellulose, Celgard, etc.) and then placed between the Fe negative electrode and the Ni positive electrode. The battery can then be filled with an electrolyte solution containing a sulfide (e.g., 5.95M KOH, 0.05M LiOH, 0.01M Na2S) and cycled normally. In some embodiments, lignin, lignin sulfonate, or a mixture of the two is coated on a membrane (e.g., cellulose, Celgard, etc.) and then placed between the Fe negative electrode and the Ni positive electrode containing a sulfide source. The battery can then be filled with a sulfide-free electrolyte solution (e.g., 5.95M KOH, 0.05M LiOH) and cycled normally. In some embodiments, lignin, lignin sulfonate, or a mixture of the two is coated on a membrane (e.g., cellulose, Celgard, etc.) and then placed between the Fe negative electrode and the Ni positive electrode containing a sulfide source. The cell can then be filled with a sulfide containing electrolyte solution (e.g., 5.95M KOH, 0.05M LiOH, 0.01M Na2S) and cycled normally.

[0203] Multiple embodiments may provide devices and / or methods for large-capacity energy storage systems, such as long-duration energy storage (LODES) systems, short-duration energy storage (SDES) systems, and the like. As an example, multiple embodiments may provide battery packs for large-capacity energy storage systems, such as battery packs for LODES systems. Renewable energy sources are becoming increasingly common and cost-effective. However, many renewable energy sources face intermittency issues that hinder the adoption of renewable energy sources. The impact of the intermittent trend of renewable energy sources can be mitigated by pairing renewable energy sources with large-capacity energy storage systems, such as LODES systems, SDES systems, and the like. In order to support the use of combined power generation, transmission, and storage systems (e.g., power plants with renewable power generation sources paired with large-capacity energy storage systems and transmission facilities located at either power plants and / or large-capacity energy storage systems), it is necessary to support the design and operation of such combined power generation, transmission, and storage systems. Devices and methods, such as the devices and methods of multiple embodiments described herein.

[0204] The combined power generation, transmission and storage system can be a power plant including one or more power generation sources (e.g., one or more renewable energy power generation sources, one or more non-renewable energy power generation sources, a combination of renewable energy and non-renewable energy power generation sources, etc.), one or more transmission facilities, and one or more large-capacity energy storage systems. The transmission facilities at any one of the power plant and / or the large-capacity energy storage system can be jointly optimized with the power generation and storage system, or constraints can be imposed on the design and operation of the power generation and storage system. The combined power generation, transmission and storage system can be configured to meet multiple output targets under multiple design and operation constraints.

[0205] Figure 8-16 Various exemplary systems are shown, wherein one or more aspects of various embodiments can be used as part of a bulk energy storage system such as a LODES system, a SDES system, etc. For example, reference is made herein to Figure 1-16 The described multiple embodiments can be used as battery packs for large-capacity energy storage systems such as LODES systems, SDES systems, etc., and / or, the multiple electrodes described herein can be used as components of large-capacity energy storage systems. As used herein, the term "LODES system" can refer to a large-capacity energy storage system configured to have a rated duration (energy / power ratio) of 24 hours (h) or longer (such as a duration of 24h, a duration of 24h to 50h, a duration greater than 50 hours, a duration of 24h to 150h, a duration greater than 150h, a duration of 24h to 200h, a duration greater than 200h, a duration of 24h to 500h, a duration greater than 500h, etc.).

[0206] Figure 8An exemplary system is shown in which one or more aspects of multiple embodiments can be used as part of a large-capacity energy storage system. As a specific example, a large-capacity energy storage system incorporating one or more aspects of multiple embodiments can be a LODES system 2404. As an example, the LODES system 2404 can include a battery pack of multiple embodiments described herein, multiple electrodes described herein, etc. The LODES system 2404 can be electrically connected to a wind farm 2402 and one or more transmission facilities 2406. The wind farm 2402 can be electrically connected to the transmission facility 2406. The transmission facility 2406 can be electrically connected to the power grid 2408. The wind farm 2402 can generate electricity, and the wind farm 2402 can output the generated electricity to the LODES system 2404 and / or the transmission facility 2406. The LODES system 2404 can store electricity received from the wind farm 2402 and / or the transmission facility 2406. The LODES system 2404 can output the stored electricity to the transmission facility 2406. The transmission facility 2406 may output power received from one or both of the wind farm 2402 and the LODES system 2404 to the grid 2408, and / or may receive power from the grid 2408 and output the power to the LODES system 2404. The wind farm 2402, the LODES system 2404, and the transmission facility 2406 may together constitute a power plant 2400, which may be a combined power generation, transmission, and storage system. The power generated by the wind farm 2402 may be supplied directly to the grid 2408 via the transmission facility 2406, or may be first stored in the LODES system 2404. In some cases, the power supplied to the grid 2408 may come entirely from the wind farm 2402, entirely from the LODES system 2404, or from a combination of the wind farm 2402 and the LODES system 2404. The dispatch of power from the combined wind farm 2402 and LODES system 2404 of the power plant 2400 can be controlled according to an established long-term (multi-day or even multi-year) plan, or can be controlled according to the day-ahead (24-hour forecast) market conditions, or can be controlled according to the market conditions of the previous hour, or can be controlled in response to real-time pricing signals.

[0207] As an example of the operation of power plant 2400, LODES system 2404 can be used to reshape and "fix" the electricity generated by wind farm 2402. In one such example, wind farm 2402 can have a peak power generation output (capacity) of 260 megawatts (MW) and a capacity factor (CF) of 41%. LODES system 2404 can have a rated power (capacity) of 106MW, a rated duration (energy / power ratio) of 150 hours (h), and an energy efficiency of 15,900 megawatt hours (MWh). In another such example, wind farm 2402 can have a peak power generation output (capacity) of 300MW and a capacity factor (CF) of 41%. LODES system 2404 can have a rated power of 106MW, a rated duration (energy / power ratio) of 200h, and an energy efficiency of 21,200MWh. In another such example, wind farm 2402 can have a peak power generation output (capacity) of 176MW and a capacity factor (CF) of 53%. The LODES system 2404 may have a rated power (capacity) of 88 MW, a rated duration (energy / power ratio) of 150 h, and an energy efficiency of 13,200 MWh. In another such example, the wind farm 2402 may have a peak power generation output (capacity) of 277 MW and a capacity factor (CF) of 41%. The LODES system 2404 may have a rated power (capacity) of 97 MW, a rated duration (energy / power ratio) of 50 h, and an energy efficiency of 4,850 MWh. In another such example, the wind farm 2402 may have a peak power generation output (capacity) of 315 MW and a capacity factor (CF) of 41%. The LODES system 2404 may have a rated power (capacity) of 110 MW, a rated duration (energy / power ratio) of 25 h, and an energy efficiency of 2,750 MWh.

[0208] Fig. 9 An exemplary system is shown in which one or more aspects of the various embodiments can be used as part of a bulk energy storage system. As a specific example, a bulk energy storage system incorporating one or more aspects of the various embodiments can be a LODES system 2404. As an example, the LODES system 2404 can include a battery pack of the various embodiments described herein, a plurality of electrodes described herein, and the like. Fig. 9 The system can be similar to Figure 82402. The LODES system 2404 may be electrically connected to the PV farm 2502 and one or more transmission facilities 2406. The PV farm 2502 may be electrically connected to the transmission facility 2406. The transmission facility 2406 may be electrically connected to the grid 2408. The PV farm 2502 may generate electricity and the PV farm 2502 may output the generated electricity to the LODES system 2404 and / or the transmission facility 2406. The LODES system 2404 may store the electricity received from the PV farm 2502 and / or the transmission facility 2406. The LODES system 2404 may output the stored electricity to the transmission facility 2406. The transmission facility 2406 may output the electricity received from one or both of the PV farm 2502 and the LODES system 2404 to the grid 2408, and / or may receive electricity from the grid 2408 and output the electricity to the LODES system 2404. PV farm 2502, LODES system 2404, and transmission facility 2406 together may constitute power plant 2500, which may be a combined power generation, transmission, and storage system. The power generated by PV farm 2502 may be supplied directly to grid 2408 via transmission facility 2406, or may be first stored in LODES system 2404. In some cases, the power supplied to grid 2408 may come entirely from PV farm 2502, entirely from LODES system 2404, or from a combination of PV farm 2502 and LODES system 2404. The dispatch of power from the combined PV farm 2502 and LODES system 2404 of power plant 2500 may be controlled according to a determined long-term (multi-day or even multi-year) plan, or may be controlled according to day-ahead (24-hour forecast) market conditions, or may be controlled according to market conditions one hour earlier, or may be controlled in response to real-time pricing signals.

[0209] As an example of the operation of power plant 2500, LODES system 2404 can be used to reshape and "fix" the electricity generated by PV farm 2502. In one such example, PV farm 2502 can have a peak power generation output (capacity) of 490MW and a capacity factor (CF) of 24%. LODES system 2404 can have a rated power (capacity) of 340MW, a rated duration (energy / power ratio) of 150h, and an energy efficiency of 51,000MWh. In another such example, PV farm 2502 can have a peak power generation output (capacity) of 680MW and a capacity factor (CF) of 24%. LODES system 2404 can have a rated power (capacity) of 410MW, a rated duration (energy / power ratio) of 200h, and an energy efficiency of 82,000MWh. In another such example, PV farm 2502 can have a peak power generation output (capacity) of 330MW and a capacity factor (CF) of 31%. The LODES system 2404 may have a rated power (capacity) of 215 MW, a rated duration (energy / power ratio) of 150 h, and an energy efficiency of 32,250 MWh. In another such example, the PV farm 2502 may have a peak power generation output (capacity) of 510 MW and a capacity factor (CF) of 24%. The LODES system 2404 may have a rated power (capacity) of 380 MW, a rated duration (energy / power ratio) of 50 h, and an energy efficiency of 19,000 MWh. In another such example, the PV farm 2502 may have a peak power generation output (capacity) of 630 MW and a capacity factor (CF) of 24%. The LODES system 2404 may have a rated power (capacity) of 380 MW, a rated duration (energy / power ratio) of 25 h, and an energy efficiency of 9,500 MWh.

[0210] Fig.10 An exemplary system is shown in which one or more aspects of the various embodiments can be used as part of a bulk energy storage system. As a specific example, a bulk energy storage system incorporating one or more aspects of the various embodiments can be a LODES system 2404. As an example, the LODES system 2404 can include a battery pack of the various embodiments described herein, a plurality of electrodes described herein, and the like. Fig.10 The system can be similar to Figure 8 and Fig. 9system, except that wind farm 2402 and photovoltaic (PV) farm 2502 can all be generators working together in power plant 2600. PV farm 2502, wind farm 2402, LODES system 2404 and transmission facility 2406 together can constitute power plant 2600, which can be a combined power generation, transmission and storage system. The electricity generated by PV farm 2502 and / or wind farm 2402 can be directly supplied to grid 2408 through transmission facility 2406, or can be first stored in LODES system 2404. In some cases, the electricity supplied to grid 2408 can come entirely from PV farm 2502, entirely from wind farm 2402, entirely from LODES system 2404, or from a combination of PV farm 2502, wind farm 2402 and LODES system 2404. The dispatch of electricity from the combined wind farm 2402, PV farm 2502 and LODES system 2404 from power plant 2600 can be controlled according to a determined long-term (multi-day or even multi-year) plan, or can be controlled according to the day-ahead (24-hour forecast) market conditions, or can be controlled according to the market conditions of the previous hour, or can be controlled in response to real-time pricing signals.

[0211] As an example of the operation of power plant 2600, LODES system 2404 can be used to reshape and "fix" the electricity generated by wind farm 2402 and PV farm 2502. In one such example, wind farm 2402 can have a peak power generation output (capacity) of 126MW and a capacity factor (CF) of 41%, and PV farm 2502 can have a peak power generation output (capacity) of 126MW and a capacity factor (CF) of 24%. LODES system 2404 can have a rated power (capacity) of 63MW, a rated duration (energy / power ratio) of 150h, and an energy efficiency of 9,450MWh. In another such example, wind farm 2402 can have a peak power generation output (capacity) of 170MW and a capacity factor (CF) of 41%, and PV farm 2502 can have a peak power generation output (capacity) of 110MW and a capacity factor (CF) of 24%. LODES system 2404 may have a rated power (capacity) of 57 MW, a rated duration (energy / power ratio) of 200 h, and an energy efficiency of 11,400 MWh. In another such example, wind farm 2402 may have a peak power generation output (capacity) of 105 MW and a capacity factor (CF) of 51%, and PV farm 2502 may have a peak power generation output (capacity) of 70 MW and a capacity factor (CF) of 31. LODES system 2404 may have a rated power (capacity) of 61 MW, a rated duration (energy / power ratio) of 150 h, and an energy efficiency of 9,150 MWh. In another such example, wind farm 2402 may have a peak power generation output (capacity) of 135 MW and a capacity factor (CF) of 41%, and PV farm 2502 may have a peak power generation output (capacity) of 90 MW and a capacity factor (CF) of 24%. LODES system 2404 may have a rated power (capacity) of 68 MW, a rated duration (energy / power ratio) of 50 h, and an energy efficiency of 3,400 MWh. In another such example, wind farm 2402 may have a peak power generation output (capacity) of 144 MW and a capacity factor (CF) of 41%, and PV farm 2502 may have a peak power generation output (capacity) of 96 MW and a capacity factor (CF) of 24%. LODES system 2404 may have a rated power (capacity) of 72 MW, a rated duration (energy / power ratio) of 25 h, and an energy efficiency of 1,800 MWh.

[0212] Fig.11An exemplary system is shown in which one or more aspects of multiple embodiments can be used as part of a large-capacity energy storage system. As a specific example, a large-capacity energy storage system incorporating one or more aspects of multiple embodiments can be a LODES system 2404. As an example, the LODES system 2404 can include a battery pack of multiple embodiments described herein, multiple electrodes described herein, etc. The LODES system 2404 can be electrically connected to one or more transmission facilities 2406. In this way, the LODES system 2404 can operate in a "stand-alone" manner to arbitrate energy around market prices and / or avoid transmission constraints. The LODES system 2404 can be electrically connected to one or more transmission facilities 2406. The transmission facility 2406 can be electrically connected to a power grid 2408. The LODES system 2404 can store electricity received from the transmission facility 2406. The LODES system 2404 can output the stored electricity to the transmission facility 2406. Transmission facility 2406 may output power received from LODES system 2404 to grid 2408 and / or may receive power from grid 2408 and output the power to LODES system 2404 .

[0213] LODES system 2404 and transmission facilities 2406 together can constitute power plant 900. As an example, power plant 900 can be located downstream of transmission constraints, close to the power consumption end. In such an example where power plant 2700 is located downstream, LODES system 2404 can have a duration of 24h to 500h, and can undergo one or more full discharges per year to support peak power consumption when transmission capacity is insufficient to serve customers. In addition, in such an example where power plant 2700 is located downstream, LODES system 2404 can undergo several shallow discharges (daily or at a higher frequency) to adjudicate the difference between night and daytime electricity prices and reduce the total cost of power service to customers. As a further example, power plant 2700 can be located upstream of transmission constraints, close to the power generation end. In such an example where power plant 2700 is located upstream, LODES system 2404 can have a duration of 24h to 500h, and can undergo one or more full charges per year to absorb excess power generation when transmission capacity is insufficient to distribute power to customers. Additionally, in such an example where the power plant 2700 is located upstream, the LODES system 2404 may undergo several shallow charges and discharges (daily or at a higher frequency) to arbitrate the difference between nighttime and daytime electricity prices and maximize the value of the output of the power generation facility.

[0214] Fig.12An exemplary system is shown in which one or more aspects of multiple embodiments can be used as part of a large-capacity energy storage system. As a specific example, a large-capacity energy storage system incorporating one or more aspects of multiple embodiments can be a LODES system 2404. As an example, the LODES system 2404 can include a battery pack of multiple embodiments described herein, multiple electrodes described herein, etc. The LODES system 2404 can be electrically connected to a commercial and industrial (C&I) customer 2802, such as a data center, a factory, etc. The LODES system 2404 can be electrically connected to one or more transmission facilities 2406. The transmission facility 2406 can be electrically connected to a power grid 2408. The transmission facility 2406 can receive electricity from the power grid 2408 and output the electricity to the LODES system 2404. The LODES system 2404 can store the electricity received from the transmission facility 2406. The LODES system 2404 can output the stored electricity to the C&I customer 2802. In this manner, LODES system 2404 may operate to reshape power purchased from grid 2408 to match the consumption patterns of C&I customers 2802 .

[0215] LODES system 2404 and transmission facility 2406 may together constitute power plant 2800. As an example, power plant 2800 may be located near the electricity consumption end, i.e., near C&I customer 2802, such as between power grid 2408 and C&I customer 2802. In such an example, LODES system 2404 may have a duration of 24h to 500h, and may purchase electricity from the market, thereby charging LODES system 2404 when electricity is cheaper. LODES system 2404 may then discharge to provide electricity to C&I customer 2802 when the market price is expensive, thus offsetting the market purchase of C&I customer 2802. As an alternative configuration, power plant 2800 is not located between power grid 2408 and C&I customer 2802, power plant 2800 may be located between renewable energy sources such as PV farms, wind farms, etc., and transmission facility 2406 may be connected to the renewable energy sources. In such an alternative example, the LODES system 2404 can have a duration of 24 hours to 500 hours, and the LODES system 2404 can be charged when the renewable energy output is available. Then, the LODES system 2404 can be discharged to provide electricity generated by the renewable energy to the C&I customer 2802, thereby meeting part or all of the electricity demand of the C&I customer 2802.

[0216] Fig.13An exemplary system is shown in which one or more aspects of multiple embodiments can be used as part of a large-capacity energy storage system. As a specific example, a large-capacity energy storage system incorporating one or more aspects of multiple embodiments can be a LODES system 2404. As an example, the LODES system 2404 can include a battery pack of multiple embodiments described herein, multiple electrodes described herein, etc. The LODES system 2404 can be electrically connected to a wind farm 2402 and one or more transmission facilities 2406. The wind farm 2402 can be electrically connected to the transmission facility 2406. The transmission facility 2406 can be electrically connected to a C&I customer 2802. The wind farm 2402 can generate electricity, and the wind farm 2402 can output the generated electricity to the LODES system 2404 and / or the transmission facility 2406. The LODES system 2404 can store electricity received from the wind farm 2402.

[0217] The LODES system 2404 may output the stored electricity to a transmission facility 2406. The transmission facility 2406 may output the electricity received from one or both of the wind farm 2402 and the LODES system 2404 to the C&I customer 2802. The wind farm 2402, the LODES system 2404, and the transmission facility 2406 may together constitute a power plant 2900, which may be a combined power generation, transmission, and storage system. The electricity generated by the wind farm 2402 may be supplied directly to the C&I customer 2802 via the transmission facility 2406, or may be first stored in the LODES system 2404. In some cases, the electricity supplied to the C&I customer 2802 may come entirely from the wind farm 2402, entirely from the LODES system 2404, or from a combination of the wind farm 2402 and the LODES system 2404. The LODES system 2404 may be used to reshape the electricity generated by the wind farm 2402 to match the consumption pattern of the C&I customer 2802. In one such example, the LODES system 2404 may have a duration of 24 hours to 500 hours and may be charged when the renewable energy generation of the wind farm 2402 exceeds the load of the C&I customer 2802. The LODES system 2404 may then be discharged when the renewable energy generation of the wind farm 2402 does not reach the load of the C&I customer 2802, so as to provide a reliable renewable energy profile to the C&I customer 2802 to offset some or all of the electricity consumption of the C&I customer 2802.

[0218] Fig.14An exemplary system is shown in which one or more aspects of multiple embodiments can be used as part of a large-capacity energy storage system. As a specific example, a large-capacity energy storage system incorporating one or more aspects of multiple embodiments can be a LODES system 2404. As an example, the LODES system 2404 can include a battery pack of multiple embodiments described herein, multiple electrodes described herein, etc. The LODES system 2404 can be part of a power plant 3000, which is used to integrate a large amount of renewable energy generation into a microgrid, and coordinate the renewable energy generation output by, for example, a PV electric field 2502 and a wind farm 2402 with the existing thermal power generation output by, for example, a thermal power plant 3002 (e.g., a gas power plant, a coal-fired power plant, a diesel generator set, etc., or a combination of multiple thermal power generation methods), while the renewable energy generation and thermal power generation provide high-availability loads for C&I customers 2802. A microgrid, such as a microgrid composed of a power plant 3000 and a thermal power plant 3002, can provide 90% or higher availability. The electricity generated by PV farm 2502 and / or wind farm 2402 may be supplied directly to C&I customer 2802 or may first be stored in LODES system 2404 .

[0219] In some cases, the power supplied to C&I customer 2802 may come entirely from PV farm 2502, entirely from wind farm 2402, entirely from LODES system 2404, entirely from thermal power plant 3002, or from any combination of PV farm 2502, wind farm 2402, LODES system 2404, and / or thermal power plant 3002. As an example, LODES system 2404 of power plant 3000 may have a duration of 24 hours to 500 hours. As a specific example, C&I customer 2802 load may have a peak of 100 MW, LODES system 2404 may have a rated power of 14 MW and a duration of 150 hours, the price of natural gas may be $6 per million British thermal units (MMBTU), and the renewable energy share may be 58%. As another specific example, the C&I customer 2802 load may have a peak of 100 MW, the LODES system 2404 may have a rated power of 25 MW and a duration of 150 h, the price of natural gas may be $8 / MMBTU, and the renewable energy share may be 65%.

[0220] Fig.15An exemplary system is shown in which one or more aspects of multiple embodiments can be used as part of a bulk energy storage system. As a specific example, a bulk energy storage system incorporating one or more aspects of multiple embodiments can be a LODES system 2404. As an example, the LODES system 2404 can include a battery pack of multiple embodiments described herein, multiple electrodes described herein, etc. The LODES system 2404 can be used to supplement a nuclear power plant 3102 (or other inflexible power generation facilities, such as thermal power plants, biomass power plants, etc., and / or any other type of power plant with a ramp rate of less than 50% of rated power for one hour and a high capacity factor of 80% or more) to increase the flexibility of the combined output of the power plant 3100 consisting of the combined LODES system 2404 and the nuclear power plant 3102. The nuclear power plant 3102 can be operated at a high capacity factor and at the highest efficiency point, while the LODES system 2404 can be charged and discharged to effectively reshape the output of the nuclear power plant 3102 to match customer power consumption and / or market electricity prices. As an example, the LODES system 2404 of the power plant 3100 may have a duration of 24h to 500h. In a specific example, the nuclear power plant 3102 may have a rated output of 1000MW, and due to low market electricity prices, the nuclear power plant 3102 may be forced to enter a long period of minimum stable power generation or even shut down. The LODES system 2404 can avoid facility shutdown and charge when market prices are low; the LODES system 2404 can then discharge and increase total output power generation when market pricing is high.

[0221] Fig.16An exemplary system is shown, in which one or more aspects of multiple embodiments can be used as part of a large-capacity energy storage system. As a specific example, a large-capacity energy storage system incorporating one or more aspects of multiple embodiments can be a LODES system 2404. As an example, the LODES system 2404 can include a battery pack of multiple embodiments described herein, multiple electrodes described herein, etc. The LODES system 2404 can operate in conjunction with the SDES system 3202. The LODES system 2404 and the SDES system 3202 together can constitute a power plant 3200. As an example, the LODES system 2404 and the SDES system 3202 can be optimized together, whereby the LODES system 2404 can provide a variety of services, including long-term backup and / or bridging multi-day fluctuations (e.g., multi-day fluctuations in market pricing, renewable energy generation, power consumption, etc.), and the SDES system 3202 can provide a variety of services, including fast auxiliary services (e.g., voltage control, frequency regulation, etc.) and / or bridging intraday fluctuations (e.g., intraday fluctuations in market pricing, renewable energy generation, power consumption, etc.). The SDES system 3202 may have a duration of less than 10 hours and a round trip efficiency greater than 80%. The LODES system 2404 may have a duration of 24h to 500h and a round trip efficiency greater than 40%. In one such example, the LODES system 2404 may have a duration of 150 hours and support a customer's electricity consumption for up to one week of insufficient renewable energy generation. The LODES system 2404 may also support customer electricity consumption during an intraday power generation shortage event, supplementing the capabilities of the SDES system 3202. In addition, the SDES system 3202 may provide power to customers during an intraday power generation shortage event and provide power regulation and quality services such as voltage regulation and frequency regulation.

[0222] Various examples of aspects of various embodiments are described in the following paragraphs.

[0223] Example 1. A battery comprising: a first electrode comprising iron; an electrolyte; and a second electrode, wherein the first electrode or the electrolyte comprises an additive. Example 2. The battery according to Example 1, wherein the additive comprises an element having low hydrogen evolution reaction (HER) activity and / or improving charging of the first electrode. Example 3. The battery according to any one of Examples 1-2, wherein the iron comprises direct reduced iron (DRI) and / or another sponge iron powder. Example 4. The battery according to any one of Examples 1-3, wherein the element comprises tin and / or antimony. Example 5. The battery according to Example 4, wherein the additive comprises sodium stannate trihydrate (Na2SnO3·3H2O), metallic tin, potassium stannate trihydrate (K2SnO3·3H2O), tin oxide (SnO2), cylindrical cassiterite (Pb3Sn4FeSb2S14 ), copper iron tin sulfide (Cu2FeSnS 4), lead-tin alloy (60 / 40Sn / Pb solder; 63 / 37Sn / Pb solder; Terne I alloy: 10-20% Sn, balance Pb), zinc-tin alloy (Terne II alloy: 10-20% Sn, balance Zn), or tin sulfide (SnS or SnS2). Example 6. A battery pack according to any one of Examples 1-5, wherein the concentration of the additive in the electrolyte is 0.1 mM or greater. Example 7. A battery pack according to Example 6, wherein the concentration of the additive in the electrolyte is about 10 mM. Example 8. A battery pack according to Example 6, wherein the concentration of the additive in the electrolyte is about 100 mM. Example 9. A battery pack according to Example 6, wherein the concentration of the additive in the electrolyte is about 10 mM to about 100 mM. Example 10. The battery pack according to Example 6, wherein the concentration of the additive in the electrolyte is about 650 mM, or wherein the concentration of the additive in the electrolyte is about 50 mM. Example 11. The battery pack according to Example 6, wherein the concentration of the additive in the electrolyte is about 670 mM. Example 12. The battery pack according to Example 6, wherein the concentration of the additive in the electrolyte is about 750 mM. Example 13. The battery pack according to Example 6, wherein the additive is at or below the saturation limit in the electrolyte. Example 14. The battery pack according to any one of Examples 1-5, wherein the amount of the additive in the first electrode is about 0.1 wt % to about 20 wt % of the first electrode. Example 15. The battery pack according to Example 14, wherein the amount of the additive in the first electrode is about 1 wt %. Example 16. The battery pack according to Example 14, wherein the amount of the additive in the first electrode is about 6 wt %. Example 17. The battery pack according to Example 14, wherein the amount of the additive in the first electrode is about 1 wt % to 10 wt %. Example 18. A battery according to any one of Examples 1-17, wherein the electrolyte comprises lithium hydroxide (LiOH), potassium hydroxide (KOH) and / or sodium hydroxide (NaOH), and optionally sodium sulfide (Na2S). Example 19. A battery according to any one of Examples 1-18, wherein the additive is plated on the second electrode. Example 20. A battery according to any one of Examples 1-19, wherein the additive is placed in a reservoir suspended in the electrolyte. Example 21. A battery according to any one of Examples 1-3 and 18-20, wherein the additive comprises antimony. Example 22. A battery according to any one of Examples 1-21, wherein the electrolyte comprises one or more hydroxides, and the total hydroxide concentration in the electrolyte is about 6M or greater. Example 23. A battery according to any one of Examples 1-21, wherein the electrolyte comprises one or more hydroxides, and the total hydroxide concentration in the electrolyte is greater than 7M.Example 24. The battery pack according to Example 23, wherein the total hydroxide concentration in the electrolyte is greater than 7M and less than or equal to 11M. Example 25. The battery pack according to Example 24, wherein the electrolyte comprises greater than 6M of KOH and NaOH combined and greater than or equal to 0.05M LiOH. Example 26. The battery pack according to Example 24, wherein the electrolyte comprises greater concentrations of KOH, NaOH, and LiOH such that the molar concentration of KOH is greater than the molar concentration of NaOH and the molar concentration of NaOH is greater than the molar concentration of LiOH. Example 27. The battery pack according to Example 23, wherein the total hydroxide concentration in the electrolyte is greater than 7M and less than 10M. Example 28. The battery pack according to Example 23, wherein the total hydroxide concentration in the electrolyte is greater than 7.5M and less than 9.5M. Example 29. The battery pack according to any of Examples 27-28, wherein the electrolyte comprises KOH. Embodiment 30. A battery pack according to any one of embodiments 22-29, wherein the electrolyte comprises at least 0.05M LiOH. Embodiment 31. A battery pack according to any one of embodiments 22-30, wherein the electrolyte comprises any one or more of KOH, NaOH, LiOH, RbOH, CsOH, FrOH, Be(OH)2, Ca(OH)2, Mg(OH)2, Sr(OH)2, Ra(OH)2, Ba(OH)2, and mixtures thereof. Embodiment 32. A battery pack according to any one of embodiments 22-31, wherein the electrolyte comprises a sulfide. Embodiment 33. A battery pack according to embodiment 32, wherein the concentration of sulfide in the electrolyte is 0.001M to 0.5M. Embodiment 34. A battery pack according to any one of embodiments 21-30, wherein the electrolyte does not comprise a sulfide. Embodiment 35. A battery pack according to any one of embodiments 1-34, wherein the additive is at least partially solid. Embodiment 36. A battery according to Embodiment 35, wherein the surface area of ​​the solid is selected to provide a level of reactivity such that there is a constant flux of additives into the liquid electrolyte phase and / or to maintain the concentration of the additive in the liquid electrolyte phase at or above a selected concentration.

[0224] Embodiment 37. A battery comprising: a first electrode comprising iron; an electrolyte; and a second electrode, wherein the electrolyte comprises one or more hydroxides.

[0225] Embodiment 38. The battery of Embodiment 37, wherein the iron is direct reduced iron (DRI) or another sponge iron powder.

[0226] Embodiment 39. A battery pack comprising: a first electrode comprising direct reduced iron (DRI) or another sponge iron powder; an electrolyte comprising a hydroxide; and a second electrode, wherein the first electrode or the electrolyte further comprises an additive comprising at least one of tin, lead or antimony.

[0227] Example 40. A battery according to any one of Examples 37-39, wherein the total hydroxide concentration in the electrolyte is about 6M or greater. Example 41. A battery according to any one of Examples 37-39, wherein the total hydroxide concentration in the electrolyte is greater than 7M. Example 42. A battery according to Example 41, wherein the total hydroxide concentration in the electrolyte is greater than 7M and less than or equal to 11M. Example 43. A battery according to Example 42, wherein the electrolyte comprises greater than 6M of a combination of KOH and NaOH and greater than or equal to 0.05M of LiOH. Example 44. A battery according to Example 42, wherein the electrolyte comprises greater concentrations of KOH, NaOH, and LiOH such that the molar concentration of KOH is greater than the molar concentration of NaOH and the molar concentration of NaOH is greater than the molar concentration of LiOH. Example 45. A battery according to any one of Examples 37-39, wherein the total hydroxide concentration in the electrolyte is greater than 7M and less than 10M. Embodiment 46. The battery pack according to any one of embodiments 37-39, wherein the total hydroxide concentration in the electrolyte is greater than 7.5M and less than 9.5M. Embodiment 47. The battery pack according to any one of embodiments 45-46, wherein the electrolyte comprises KOH. Embodiment 48. The battery pack according to any one of embodiments 37-47, wherein the electrolyte comprises at least 0.05M LiOH. Embodiment 49. The battery pack according to any one of embodiments 37-48, wherein the electrolyte comprises any one or more of KOH, NaOH, LiOH, RbOH, CsOH, FrOH, Be(OH)2, Ca(OH)2, Mg(OH)2, Sr(OH)2, Ra(OH)2, Ba(OH)2, and mixtures thereof. Embodiment 50. The battery pack according to any one of embodiments 37-49, wherein the electrolyte comprises a sulfide. Embodiment 51. The battery pack according to embodiment 50, wherein the sulfide concentration in the electrolyte is 0.001M to 0.5M. Embodiment 52. The battery of any of Embodiments 37-49, wherein the electrolyte does not contain sulfides.

[0228] Example 53. A large-capacity energy storage system, comprising: a stack of one or more battery packs, wherein at least one of the one or more battery packs includes the battery pack of any one of Examples 1-52. Example 54. A large-capacity energy storage system according to Example 53, wherein the large-capacity energy storage system is a long-duration energy storage (LODES) system. Example 55. A large-capacity energy storage system according to Example 54, wherein the LODES system is configured to discharge for a time greater than 24 hours. Example 56. A large-capacity energy storage system according to Example 55, wherein the LODES system is configured to discharge for a time greater than 30 hours. Example 57. A large-capacity energy storage system according to Example 55, wherein the LODES system is configured to discharge for a time greater than 100 hours. Example 58. A large-capacity energy storage system according to Example 55, wherein the LODES system is configured to discharge for a time greater than 150 hours.

[0229] Example 59. A method of operating a battery having an iron-based electrode, comprising: adding the additive of any one of Examples 1-36 to the battery; and / or adding the hydroxide of any one of Examples 37-52 to the battery. Example 60. The method of Example 59, wherein the iron-based electrode comprises DRI or another sponge iron powder. Example 61. The method of Example 59, further comprising adding one or more organic additives to the electrolyte of the battery. Example 62. The method of Example 61, wherein the one or more organic additives include one or more alkyl polyglucosides. Example 63. The method of any one of Examples 59-62, further comprising incorporating tin into the current collector of the battery. Example 64. The method of any one of Examples 59-62, further comprising incorporating the selected additive into the powder mixture used to produce the sponge iron before reducing the sponge iron. Example 65. The method of any one of Examples 59-64, further comprising adding a HOR catalyst to the battery. Embodiment 66. The method according to any one of embodiments 59-65, further comprising capturing hydrogen in soluble or quasi-soluble form. Embodiment 67. The method according to any one of embodiments 59-66, further comprising: adding an additive to the anode and / or electrolyte to reduce the migration of sulfide to the positive electrode or consume sulfide or sulfate released from the anode; and / or adding an anion selective membrane or separator to prevent the migration of specific ions. Embodiment 68. The method according to embodiment 67, wherein the additive and / or the anion selective membrane or separator comprises lignin and its derivatives, such as lignin sulfonate.

[0230] Embodiment 69. A method comprising adding one or more organic additives to an electrolyte of a battery. Embodiment 70. The method of embodiment 69, wherein the one or more organic additives comprise one or more alkyl polyglucosides.

[0231] Embodiment 71. A method comprising incorporating tin into a current collector of a battery.

[0232] Example 72. A process comprising incorporating a selected additive into a powder mix for producing sponge iron prior to reducing the sponge iron and forming a battery electrode from the produced sponge iron.

[0233] Embodiment 73. A method comprising adding a HOR catalyst to a battery stack.

[0234] Embodiment 74. A method comprising capturing hydrogen in a soluble or quasi-soluble form.

[0235] Embodiment 75. A method comprising: adding an additive to an anode and / or electrolyte of a battery to reduce the migration of sulfide to the positive electrode or consume sulfide or sulfate released from the anode; and / or adding an anion selective membrane or separator to the battery to prevent the migration of specific ions. Embodiment 76. The method according to embodiment 75, wherein the additive and / or the anion selective membrane or separator comprises lignin and its derivatives, such as lignin sulfonate.

[0236] Embodiment 77. The battery pack according to any one of embodiments 1-52 and / or the large-capacity energy storage system according to any one of embodiments 53-58, wherein the electrolyte comprises one or more organic additives. Embodiment 78. The battery pack and / or the large-capacity energy storage system according to embodiment 77, wherein the one or more organic additives comprise one or more alkyl polyglucosides.

[0237] Embodiment 79. The battery pack according to any one of embodiments 1-52, 77 and 78 and / or the large-capacity energy storage system according to any one of embodiments 53-58, 77 and 78, further comprising a current collector in which tin is doped.

[0238] Embodiment 80. A battery pack according to any one of embodiments 1-52 and 77-79 and / or a large-capacity energy storage system according to any one of embodiments 53-58 and 77-79, wherein the DRI or another sponge iron powder contains selected additives that have been incorporated into the powder mixture used to produce the DRI or another sponge iron powder.

[0239] Embodiment 81. The battery pack according to any one of embodiments 1-52 and 77-80 and / or the large-capacity energy storage system according to any one of embodiments 53-58 and 77-80, further comprising a HOR catalyst and / or a hydrogen absorber.

[0240] Embodiment 82. A battery pack according to any one of embodiments 1-52 and 77-81 and / or a large-capacity energy storage system according to any one of embodiments 53-58 and 77-81, further comprising: an additive in the first electrode and / or electrolyte to reduce the migration of sulfide to the second electrode or consume the sulfide or sulfate released from the first electrode; and / or an anion selective membrane or separator to prevent the migration of specific ions. Embodiment 83. A battery pack and / or a large-capacity energy storage system according to embodiment 82, wherein the additive and / or the anion selective membrane or separator comprises lignin and its derivatives, such as lignin sulfonate.

[0241] Embodiment 84. A battery and / or a large-capacity energy storage system, wherein the electrolyte comprises one or more organic additives. Embodiment 85. A battery and / or a large-capacity energy storage system according to embodiment 84, wherein the one or more organic additives comprise one or more alkyl polyglucosides.

[0242] Embodiment 86. A battery pack and / or a large-capacity energy storage system, wherein the current collector has tin incorporated therein.

[0243] Embodiment 87. A battery pack and / or large-capacity energy storage system having an electrode comprising DRI or another sponge iron powder, wherein the DRI or another sponge iron powder contains selected additives that have been incorporated into the powder mixture used to produce the DRI or another sponge iron powder.

[0244] Embodiment 88. A battery pack and / or a large-capacity energy storage system comprising a HOR catalyst and / or a hydrogen absorber.

[0245] Embodiment 89. A battery and / or a large-capacity energy storage system, comprising: an additive in the first electrode and / or electrolyte to reduce the migration of sulfide to the second electrode or consume the sulfide or sulfate released from the first electrode; and / or an anion selective membrane or separator to prevent the migration of specific ions. Embodiment 90. A battery and / or a large-capacity energy storage system according to embodiment 89, wherein the additive and / or the anion selective membrane or separator comprises lignin and its derivatives, such as lignin sulfonate.

[0246] Embodiment 1A. A battery comprising: a first electrode comprising direct reduced iron (DRI) or another sponge iron powder; an electrolyte; and a second electrode, wherein the first electrode or the electrolyte comprises an additive, the additive comprising an element having low hydrogen evolution reaction (HER) activity and / or improving the characteristics of the battery. Embodiment 2A. The battery according to embodiment 1A, wherein improving the characteristics of the battery comprises one or more of the following: improving the charging of the first electrode; improving the conditioning process of the first electrode; improving the reversibility of the half-cell reaction of the first electrode; improving the discharge capacity of the first electrode. Embodiment 3A. The battery according to any one of embodiments 1A or 2A, wherein the element comprises tin, antimony and / or indium. Embodiment 4A. The battery according to embodiment 3A, wherein the additive comprises sodium stannate trihydrate (Na2SnO3·3H2O), metallic tin, potassium stannate trihydrate (K2SnO3·3H2O), tin oxide (SnO2), cylindrical cassiterite (Pb3Sn4FeSb2S 14 ), copper iron tin sulfide (Cu2FeSnS 4 ), lead-tin alloy (60 / 40Sn / Pb solder; 63 / 37Sn / Pb solder; Terne I alloy: 10-20% Sn, the balance is Pb), zinc-tin alloy (Terne II alloy: 10-20% Sn, the balance is Zn), iron tin oxide (FeSnO3), tin sulfide (SnS or SnS2), or a mixture thereof. Example 5A. A battery pack according to Example 3A, wherein the additive includes antimony dialkyl dithiophosphate (SbC 18 H 42 O6P3S6), antimony selenide (Sb2Se3), antimony (III) oxide (Sb2O3), antimony (V) oxide (Sb2O5), metallic antimony, antimony acetate (SbC6H9O6), antimony potassium tartrate (Sb2K2C8H4O 12 ), sodium antimony tartrate (Sb2Na2C8H4O 12), antimony sulfate (Sb2(SO4)3), antimony (III) sulfide (Sb2S3), potassium antimonate trihydrate (KSb2O3·3H2O), or a mixture thereof. Example 6A. A battery pack according to Example 3A, wherein the additive comprises metal indium (In), indium (III) chloride (InCl3), indium (III) hydroxide (In(OH)3), indium (III) oxide (In2O3), indium (III) sulfate (In2(SO4)3), indium (III) sulfide (In2S3), indium phosphide (InP), indium (III) acetate (In(C3H3O2)3), indium (III) nitrate (In(NO3)3), indium (III) sulfide (In2S3), indium (I II) selenide (In2Se3), indium nitride (InN), indium (III) iodide (InI3), indium acetylacetonate (In(C5H8O2)3 or In(acac)3), indium fluoride (InF3), indium arsenide (InAs), indium telluride (In2Te3), indium (III) bromide (InBr3), indium (I) oxide (In2O), indium (II) oxide (InO), indium (II) selenide (InSe), indium (I) bromide (InBr), indium antimonide (InSb) or a mixture thereof. Example 7A. A battery pack according to any of Examples 1A-6A, wherein the concentration of the additive in the electrolyte is 0.1 mM or greater. Example 8A. A battery pack according to Example 7A, wherein the concentration of the additive in the electrolyte is about 0.1 mM to about 10 mM. Example 9A. A battery pack according to Example 7A, wherein the concentration of the additive in the electrolyte is about 10 mM to about 100 mM. Embodiment 10A. A battery according to any one of Embodiments 1A-6A, wherein the amount of the additive in the first electrode is about 0.1 wt % to about 40 wt % of the first electrode. Embodiment 11A. A battery according to Embodiment 10A, wherein the amount of the additive in the first electrode is about 10 wt % to about 35 wt %. Embodiment 12A. A battery according to Embodiment 10A, wherein the amount of the additive in the first electrode is about 15 wt % to about 20 wt %. Embodiment 13A. A battery according to any one of Embodiments 1A-12A, wherein the electrolyte comprises potassium hydroxide (KOH) and / or sodium hydroxide (NaOH), and optionally sodium sulfide (Na2S) and lithium hydroxide (LiOH). Embodiment 14A. A battery according to any one of Embodiments 1A-13A, wherein the additive is plated on the second electrode, electrodeposited on the second electrode, or placed in a reservoir suspended in the electrolyte. Embodiment 15A. A battery according to any one of Embodiments 1A-14A, wherein the electrolyte comprises a sulfide. Embodiment 16A. The battery according to Embodiment 15A, wherein the sulfide concentration in the electrolyte is 0.00001M to 0.5M.Embodiment 17A. A battery according to any one of Embodiments 1A-14A, wherein the electrolyte does not contain a sulfide. Embodiment 18A. A battery according to any one of Embodiments 1A-17A, wherein the additive is at least partially solid. Embodiment 19A. A battery according to Embodiment 18, wherein the surface area of ​​the solid is selected to provide a reactivity level such that there is a constant flux of additive into the liquid electrolyte phase, and / or to maintain the concentration of the additive in the liquid electrolyte phase at or above a selected concentration. Embodiment 20A. A battery comprising: a first electrode comprising direct reduced iron (DRI) or another sponge iron powder; an electrolyte comprising a hydroxide; and a second electrode, wherein the first electrode or the electrolyte further comprises an additive comprising at least one of tin, lead, indium, or antimony. Embodiment 21A. A battery according to Embodiment 20A, wherein the total hydroxide concentration in the electrolyte is about 6M or greater. Embodiment 22A. A battery according to Embodiment 21A, wherein the total hydroxide concentration in the electrolyte is about 6.5M or greater. Embodiment 23A. The battery of Embodiment 22A, wherein the total hydroxide concentration in the electrolyte is greater than about 7 M or greater. Embodiment 24A. The battery of Embodiment 23A, wherein the total hydroxide concentration in the electrolyte is greater than about 7.5 M or greater. Embodiment 25A. The battery of any one of Embodiments 21A-24A, wherein the electrolyte comprises KOH. Embodiment 26A. The battery of any one of Embodiments 21A-25A, wherein the electrolyte comprises at least 0.05 M LiOH. Embodiment 27A. The battery of any one of Embodiments 21A-24A, wherein the electrolyte comprises any one or more of KOH, NaOH, LiOH, RbOH, CsOH, FrOH, Be(OH)2, Ca(OH)2, Mg(OH)2, Sr(OH)2, Ra(OH)2, Ba(OH)2, and mixtures thereof. Embodiment 28A. The battery of any one of Embodiments 21A-27A, wherein the electrolyte comprises a sulfide. Embodiment 29A. A battery pack according to Embodiment 28A, wherein the sulfide concentration in the electrolyte is 0.00001M to 0.5M. Embodiment 30A. A battery pack according to any one of Embodiments 21A-27A, wherein the electrolyte does not contain sulfides. Embodiment 31. A battery pack according to any one of Embodiments 1-30, wherein the first electrode has a discharge capacity greater than 300mAh / g, such as greater than 350mAh / g or greater than 400mAh / g. Embodiment 32. A battery pack according to any one of Embodiments 1-30, wherein the first electrode has a discharge potential greater than 0.75V, such as greater than 0.8V, greater than 0.85V, greater than 0.9V, etc.Embodiment 33A. A large-capacity energy storage system, comprising: a stack of one or more battery packs, wherein at least one of the one or more battery packs comprises the battery pack of any one of Embodiments 1A-32A. Embodiment 34A. A large-capacity energy storage system according to Embodiment 34A, wherein the large-capacity energy storage system is a long-duration energy storage (LODES) system.

[0247] The foregoing method description is provided only as an illustrative example and is not intended to require or imply that the steps of the multiple embodiments must be performed in the order presented. As will be appreciated by those skilled in the art, the order of the steps in the foregoing embodiments can be performed in any order. For example, words such as "thereafter", "then", "next step" are not necessarily intended to limit the order of steps; these words can be used to guide the reader through the description of the method. In addition, singular forms such as the use of articles ("a", "an" or "said") to mention claim elements should not be interpreted as limiting the element to the singular.

[0248] The foregoing description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the described embodiments. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the scope of the present disclosure. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but to conform to the broadest scope consistent with the appended claims and the principles and novel features disclosed herein.

Claims

1. A battery pack comprising: a first electrode comprising direct reduced iron (DRI) or another sponge iron powder; Electrolytes; and The second electrode, in, The first electrode or the electrolyte includes an additive containing an element having low hydrogen evolution reaction (HER) activity and / or improving characteristics of the battery.

2. The battery pack according to claim 1, wherein: Improving the characteristics of the battery pack includes one or more of the following: improving charging of the first electrode; improving the regulation process of the first electrode; improving the reversibility of the half-cell reaction of the first electrode; and The discharge capacity of the first electrode is improved.

3. The battery pack according to claim 1 or 2, wherein: The elements include tin, antimony and / or indium.

4. The battery pack according to claim 3, wherein: The additives include sodium stannate trihydrate (Na2SnO3·3H2O), metallic tin, potassium stannate trihydrate (K2SnO3·3H2O), tin oxide (SnO2), cylindrical cassiterite (Pb3Sn4FeSb2S 14 ), copper iron tin sulfide (Cu2FeSnS4), lead tin alloy (60 / 40Sn / Pb solder; 63 / 37Sn / Pb solder; Terne I alloy: 10-20% Sn, the balance is Pb), zinc tin alloy (Terne II alloy: 10-20% Sn, the balance is Zn), iron tin oxide (FeSnO3), tin sulfide (SnS or SnS2), or a mixture thereof.

5. The battery pack according to claim 3, wherein: The additive includes antimony dialkyl dithiophosphate (SbC 18 H 42 O6P3S6), antimony selenide (Sb2Se3), antimony (III) oxide (Sb2O3), antimony (V) oxide (Sb2O5), metallic antimony, antimony acetate (SbC6H9O6), antimony potassium tartrate (Sb2K2C8H4O 12 ), sodium antimony tartrate (Sb2Na2C8H4O 12 ), antimony sulfate (Sb2(SO4)3), antimony (III) sulfide (Sb2S3), potassium antimonate trihydrate (KSb2O3·3H2O), or a mixture thereof.

6. The battery pack according to claim 3, wherein: The additives include metal indium (In), indium (III) chloride (InCl3), indium (III) hydroxide (In(OH)3), indium (III) oxide (In2O3), indium (III) sulfate (In2(SO4)3), indium (III) sulfide (In2S3), indium phosphide (InP), indium (III) acetate (In(C3H3O2)3), indium (III) nitrate (In(NO3)3), indium (III) sulfide (In2S3), indium (III) selenide (In 2Se3), indium nitride (InN), indium (III) iodide (InI3), indium acetylacetonate (In(C5H8O2)3 or In(acac)3), indium fluoride (InF3), indium arsenide (InAs), indium telluride (In2Te3), indium (III) bromide (InBr3), indium (I) oxide (In2O), indium (II) oxide (InO), indium (II) selenide (InSe), indium (I) bromide (InBr), indium antimonide (InSb), or a mixture thereof.

7. The battery pack according to any one of claims 1 to 6, wherein: The concentration of the additive in the electrolyte is 0.1 mM or more.

8. The battery pack according to claim 7, wherein: The concentration of the additive in the electrolyte is about 0.1 mM to about 10 mM.

9. The battery pack according to claim 7, wherein: The concentration of the additive in the electrolyte is about 10 mM to about 100 mM.

10. The battery pack according to any one of claims 1 to 6, wherein: The amount of the additive in the first electrode is about 0.1 wt % to about 40 wt % of the first electrode.

11. The battery pack according to claim 10, wherein: The amount of the additive in the first electrode is about 10 wt % to about 35 wt %.

12. The battery pack according to claim 10, wherein: The amount of the additive in the first electrode is about 15 wt % to about 20 wt %.

13. The battery pack according to any one of claims 1 to 12, wherein: The electrolyte comprises potassium hydroxide (KOH) and / or sodium hydroxide (NaOH), and optionally sodium sulfide (Na2S) and lithium hydroxide (LiOH).

14. The battery pack according to any one of claims 1 to 13, wherein: The additive is plated on the second electrode, electrodeposited on the second electrode, or placed in a reservoir suspended in the electrolyte.

15. The battery pack according to any one of claims 1 to 14, wherein: The electrolyte includes a sulfide.

16. The battery pack according to claim 15, wherein: The sulfide concentration in the electrolyte is 0.00001M to 0.5M.

17. The battery pack according to any one of claims 1 to 14, wherein: The electrolyte does not contain sulfides.

18. The battery pack according to any one of claims 1 to 17, wherein: The additive is at least partially solid.

19. The battery pack according to claim 18, wherein: The surface area of ​​the solid is selected to provide a level of reactivity such that there is a constant flux of the additive into the liquid electrolyte phase and / or to maintain the concentration of the additive in the liquid electrolyte phase at or above a selected concentration.

20. A battery pack comprising: a first electrode comprising direct reduced iron (DRI) or another sponge iron powder; an electrolyte comprising a hydroxide; and The second electrode, in, The first electrode or the electrolyte further includes an additive, and the additive includes at least one of tin, lead, indium, or antimony.

21. The battery pack according to claim 20, wherein: The total hydroxide concentration in the electrolyte is about 6 M or greater.

22. The battery pack according to claim 21, wherein: The total hydroxide concentration in the electrolyte is about 6.5 M or greater.

23. The battery pack according to claim 22, wherein: The total hydroxide concentration in the electrolyte is greater than about 7 M or greater.

24. The battery pack according to claim 23, wherein: The total hydroxide concentration in the electrolyte is greater than about 7.5 M or greater.

25. The battery pack according to any one of claims 21 to 24, wherein: The electrolyte includes KOH.

26. The battery pack according to any one of claims 21 to 25, wherein: The electrolyte comprises at least 0.05 M LiOH.

27. The battery pack according to any one of claims 21 to 24, wherein: The electrolyte comprises any one or more of KOH, NaOH, LiOH, RbOH, CsOH, FrOH, Be(OH)2, Ca(OH)2, Mg(OH)2, Sr(OH)2, Ra(OH)2, Ba(OH)2 and mixtures thereof.

28. The battery pack according to any one of claims 21 to 27, wherein: The electrolyte includes a sulfide.

29. The battery pack according to claim 28, wherein: The sulfide concentration in the electrolyte is 0.00001M to 0.5M.

30. The battery pack according to any one of claims 21 to 27, wherein: The electrolyte does not contain sulfides.

31. The battery pack according to any one of claims 1 to 30, wherein: The first electrode has a discharge capacity greater than 300 mAh / g.

32. The battery pack according to any one of claims 1 to 30, wherein: The first electrode has a discharge potential greater than 0.75V.

33. A large-capacity energy storage system, comprising: A stack of one or more battery packs, wherein At least one of the one or more battery packs comprises the battery pack of any one of claims 1-32.

34. The large-capacity energy storage system according to claim 33, wherein: The large capacity energy storage system is a long duration energy storage (LODES) system.

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