The present invention relates to a mediator-ion solid state electrolyte for a variety of aqueous batteries such as a zinc-bromine (Zn—Br2) battery and a zinc-ferrocynide battery. The disclosure further provides a battery containing such an electrolyte and methods of assembling and using such as batteries.
Batteries may be divided into two principal types, primary batteries and secondary batteries. Primary batteries may be used once and are then exhausted. Secondary batteries are also often called rechargeable batteries because after use they may be connected to an electricity supply, such as a wall socket, and recharged and used again. In secondary batteries, each charge/discharge process is called a cycle. Secondary batteries eventually reach an end of their usable life, but typically only after many charge/discharge cycles.
Secondary batteries are made up of an electrochemical cell and optionally other materials, such as a casing to protect the cell and wires or other connectors to allow the battery to interface with the outside world. An electrochemical cell includes two electrodes, the positive electrode (cathode) and the negative electrode (anode), an insulator separating the electrodes so the battery does not short out, and an electrolyte that chemically connects the electrodes.
In operation, the secondary battery exchanges chemical energy and electrical energy. During discharge of the battery, electrons (e−), which have a negative charge (−), leave the anode and travel through outside electrical conductors, such as wires in a cell phone or computer, to the cathode. In the process of traveling through these outside electrical conductors, the electrons generate an electrical current, which provides electrical energy.
At the same time, in order to keep the electrical charge of the anode and cathode neutral, an ion having a positive charge (+) leaves the anode and enters the electrolyte and then a positive ion leaves the electrolyte and enters the cathode. The ionic charge is transferred through the electrolyte.
In order to recharge the battery, the same process happens in reverse. By supplying energy to the cell, electrons are induced to leave the cathode and join the anode. At the same time, a positive ion leaves the cathode and a positive ion joins the anode to keep the overall electrode charge neutral.
Zinc (Zn) has long been considered as one of the most practical anode materials for aqueous batteries due to its low-cost, safety, reliability, and compatibility with aqueous solutions. Coupling an anode having a Zn anode active material with cathode having a liquid bromine (Br2) cathode active material can provide a low-cost battery, as bromine (Br) is abundant. In addition, the battery may have high energy properties because Br2 has a high electromotive force upon reduction.
Previous Zn—Br2 flow batteries have used two electrode chambers separated by a polymer membrane, typically a microporous or ion-exchange membrane. The polymer membrane serves both as an ionic charge transfer medium and as a separator between the Zn anode and the Br2 cathode. However, membrane-based Zn—Br2 batteries suffer from two persistent problems.
First, zincate (Zn(OH)42−) is formed at the anode when the battery is discharged. Zincate is readily dissolved in the electrolyte and crosses through the membrane to the cathode. Similarly, liquid Br2 in the cathode crosses through the membrane to the anode. The crossover of these active materials to the other electrode causes the battery to self-discharge. In addition, these active materials are not utilized efficiently when they migrate to the other electrode due to concentration gradients and react with its active material.
Second, over a number of charge/discharge cycles, Zn tends to form dendrites (small tentacles of Zn metal) from the anode to the cathode. These dendrites readily penetrate the membrane, allowing movement of liquid bromine and zincate through it, and, when they reach the cathode, they short circuit the battery. One approach to overcome the Zn-dendrite issue is to intermittently regenerate the cell to prevent zinc dendrites from puncturing the separator, but such a frequent regeneration wastes of electricity.
Aqueous Batteries with Liquid or Gaseous Reactants
Aqueous batteries allow the use of liquid or gaseous reactants at the anode or cathode, or in the catholyte or anolyte. Due to their high mobility as compared to solid reactants, liquid or gaseous reactants cross to the other side of the battery, often due to concentration gradients, where they react inappropriately and render active material inaccessible or otherwise render unavailable important battery components. Current technologies do not adequately address this problem. In addition, if the battery contains a metal-based anode, dendrites form and may penetrate any barriers between the cathode side and anode side of the battery, allowing increased inappropriate movement of liquid or gaseous reactants. In addition, the dendrites may reach all the way to the cathode and short circuit the battery.
Metal air batteries are rechargeable batteries with a metal anode and a cathode that reversibly reacts with oxygen in the air. A number of metal air batteries, including lithium (Li)-air batteries and zinc (Zn)-air batteries are being developed. However, various problems have hampered their commercial acceptance. For instance, Zn-air batteries, when used with common electrolytes, operate only at a low voltage of around 1 V. In addition, over a number of charge/discharge cycles, Zn tends to form dendrites (small tentacles of Zn metal) from the anode to the cathode, which short circuits the battery. Furthermore, carbonates tend to form when components of the alkaline anode electrolyte react with carbon dioxide in the air. These carbonate clog up the cathode, preventing efficient reaction and eventually decreasing the number of charge/discharge cycles for which the battery may be used. An acidic electrolyte cannot be used in a basic battery format because it reacts violently with Zn in the anode. Finally, Zn tends to be lost from the anode over time because zincate (Zn(OH)42−) formed when the battery is discharged migrates away from the anode in the electrolyte.
Fe-air batteries are generally operated under alkaline conditions with a theoretical voltage of 1.28 V based on the alkaline iron anode chemistry and alkaline oxygen cathode chemistry. Due to the anode and cathode overpotentials during cell operation, the practical voltage of alkaline Fe-air batteries is low, typically less than 1 V).
Air batteries using other metals suffer from similar problems. These problems have not been solved, despite the immense interest in low-cost, high-energy-density batteries in recent years.
The disclosure provides aqueous rechargeable batteries that include an anode including an anode active material, a cathode including a cathode active material or an air cathode, an anolyte including an alkali metal ion, a catholyte including the same alkali metal ion or a metal-acid catholyte, and a mediator-ion solid state electrolyte (SSE) with ion channels through with the alkali metal ion may pass as a mediator-ion. The mediator-ion solid state electrolyte prevents at least 99.9% of direct chemical reactions between the catholyte and the anolyte or anode active material and between the anolyte and cathode.
According to more specific embodiments, each of with may be combined with the above embodiment and with one another in any combinations unless clearly mutually exclusive, i) both the anolyte and the catholyte may be aqueous; ii) the anode active material may include a metal-based active material; ii-a) the metal-based active material may include elemental metal; ii-b) the metal-based anode active material may include a metal compound; ii-c) the metal-based active material may include a metal that is not an alkali metal; ii-d) the metal-based active material may include Zn; ii-e) the metal-based active material may include iron (Fe), ii-f) the metal-based active material may include aluminum (Al) or magnesium (Mg); iii) the cathode may include a liquid cathode active material and a current collector; iv) the cathode may include a gaseous cathode active material and a current collector; v) the cathode active material may include any one or a combination of liquid bromine (Br2), another halogen, ferrocyanide (K4Fe(CN)6), hydrogen peroxide, bromate, permanganate, nickel oxide, dichromate, iodate, a polysulfide and sulfur mixture, polysulfide, sulfur, manganese oxide, hypochlorite, perchlorate, copper, chlorate, manganese oxide, iron, copper, nickel oxide, perchlorate, nitrate, sodium bismuthate, tin, permanganate, chromate, tetramethoxy-p-benzoquinone, 2,6 dihydroxyanthraquinone, poly(aniline-co-m-aminophenol), polyaniline, poly(aniline-co-o-aminophenol), indigo carmine, indigo carmine, aminophenol, Ru-bipy, Ru-phen, Fe-bipy, Fe-phen, Ferroin, N-Phenylanthranilic acid, N-Ethoxychrysoidine, o-Dianisidine, Sodium diphenylamine sulfonate, Diphenylbenzidine, Diphenylamine, Viologen, Sodium 2,6-Dibromophenol-indophenol, Sodium o-Cresol indophenol, Thionine, Methylene blue, Indigotetrasulfonic acid, Indigotrisulfonic acid, Indigomono, Phenosafranin, Safranin T, Neutral red, ferrate, cuprous cyanide, metallocyanide, metal hydride, quinone, or an oxygen/air cathode with an acid or base electrolyte; vi) the cathode may be an air cathode including an oxygen evolution reaction (OER) material and an oxygen reduction reaction (ORR) material; vi-i) the air cathode may further include an acidic catholyte; vii) the anolyte may include a hydroxide of the alkali metal ion; viii) the catholyte may include a hydroxide of the alkali metal ion; ix) the catholyte may include a compound of the cathode active material and the alkali metal ion; x) the catholyte may include a metal acid catholyte; x-i) the metal in the metal acid catholyte may be cesium (Ce); x-ii) the acid in the metal acid catholyte may include methane sulfonic acid (MSA); xi) the alkali metal ion may be sodium ion (Na+) and the mediator-ion solid state electrolyte may be a Na+ solid state electrolyte; xi-i) the Na+ solid state electrolyte may be Na3.4Sc2(PO4)2.6(SiO4)0.4 (NSP); xi-ii) the Na+ solid state electrolyte may be Na3Zr2Si2PO12 (NZSP); xi) the alkali metal ion may be lithium ion (Li+) and the mediator-ion solid state electrolyte may be a Li+ solid state electrolyte; xiii-i) the Li+ solid state electrolyte may be Li1+x+yAlxTi2−xP3−ySiyO12 (LATP); xiv) the mediator-ion solid state electrolyte may prevents all direct chemical reactions between the catholyte and the anolyte or anode active material and between the anolyte and cathode; xv) the mediator-ion solid state electrolyte may have an ionic conductivity for the mediator-ion of at least 0.5×10−4 S/cm; xvi) the mediator-ion solid state electrolyte may have an ionic conductivity for the mediator-ion of at least 3×10−4 S/cm; xvii) the battery may at least 90% of the cathode active material, as calculated by comparing actual capacity to theoretical capacity; xviii) the cathode active material may be a liquid located in the catholyte, and, after discharge of the battery to 89% of its theoretical capacity, 20% or less of cathode active material may remain in the catholyte; xix) the cathode active material may be a liquid located in the catholyte, and, after discharge to a cutoff voltage of 45% of the battery's OCR, 5% or less of the cathode active material may remain in the catholyte; xx) the battery may have a substantially flat configuration and a power density of at least 10 mW/cm2; xvii) the battery may have a substantially flat configuration and a current density of at least 8 mA/cm2.
The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.
Embodiments of the present invention may be better understood through reference to the following figures in which:
This disclosure provides an aqueous battery that uses a mediator-ion, including a mediator-ion solid state electrolyte. The mediator-ion may be present in both the catholyte and the anolyte and may pass through ion channels in the mediator-ion solid state electrolyte. In particular examples, the battery may be a rechargeable aqueous metal-halogen battery or a rechargeable aqueous metal-ferrocynide battery, both with a mediator-ion solid state electrolyte.
In general, the aqueous battery has an anode side and a cathode side, separated by the mediator-ion solid state electrolyte. An anolyte is present on the anode side of the battery and a catholyte is present on the cathode side. One or both of the anolyte or catholyte is aqueous. The anolyte and catholyte contain the mediator-ion. The mediator-ion solid state electrolyte allows the mediator-ion to pass through ion channels. It chemically isolates the anolyte and the catholyte because it does not substantially allow passage of larger chemical species that will detrimentally chemically react with other chemical species on the other side of the battery. For instance, in a zinc-anode battery, the mediator-ion solid state electrolyte does not substantially allow the passage of zincate to the cathode side of the battery. In addition, because the mediator-ion solid state electrolyte substantially chemically isolates the anolyte and the catholyte, different electrolytes may be used for both. The mediator-ion solid state electrolyte may also have sufficient mechanical integrity to substantially block most dendrites when they reach it, preventing breach of the mediator-ion solid state electrolyte by dendrites. The battery design is robust and can accommodate anode and cathode active materials in solid, liquid, and gaseous phases.
The metal-based anode reactive material may include solid metal that may form a metal compound upon chemical reaction with the anolyte. Zn is used as an example metal throughout this disclosure, but other metals, such as, iron (Fe), aluminum (Al), and magnesium (Mg) may also be used in place of Zn. Some examples using Fe are also provided. In some cases where the metal-based anode active material includes a metal compound, the metal compound may be dissolved or suspended in the anolyte or otherwise part of the anolyte, in which case the part of anode 20 will occupy the same portion of battery 10 as the anolyte.
Battery 10 also includes cathode 30, which contains a cathode active material or, in the case of an air battery, an oxygen evolution reaction (OER) material and an oxygen reduction reaction (ORR) material. The cathode active material may be an element or a compound, such as a halogen, particularly bromine, or ferrocyanide. The cathode active material may be present as a solid, or it may be present as a liquid or gas, which may be mixed with the catholyte. Particularly if the cathode active material is a liquid or gas, cathode 30 may include a current collector, such as metal foil or sheet or thin bound layer, or a thin sheet of electrically conductive carbon. A carbon or metal matrix may also be used as a current collector and to facilitate electrochemical reaction of a liquid or gas cathode active material. Furthermore, particularly if the cathode active material is a liquid or gas mixed with catholyte or a compound dissolved or suspended in the catholyte, part of cathode 30 will occupy the same portion of battery 10 as the catholyte.
Liquid bromine (Br2) is used as an example cathode active material throughout this disclosure, but other cathode active materials may be used alone or in combination with themselves or liquid bromine. Suitable cathode active materials include hydrogen peroxide, bromate, permanganate, nickel oxide, dichromate, iodate, a polysulfide and sulfur mixture, polysulfide, sulfur, manganese oxide, hypochlorite, perchlorate, copper, chlorate, manganese oxide, iron, copper, nickel oxide, perchlorate, nitrate, sodium bismuthate, tin, permanganate, chromate, tetramethoxy-p-benzoquinone, 2,6 dihydroxyanthraquinone, ferrocyanide, poly(aniline-co-m-aminophenol), polyaniline, poly(aniline-co-o-aminophenol), indigo carmine, indigo carmine, aminophenol, Ru-bipy, Ru-phen, Fe-bipy, Fe-phen, Ferroin, N-Phenylanthranilic acid, N-Ethoxychrysoidine, o-Dianisidine, Sodium diphenylamine sulfonate, Diphenylbenzidine, Diphenylamine, Viologen, Sodium 2,6-Dibromophenol-indophenol, Sodium o-Cresol indophenol, Thionine, Methylene blue, Indigotetrasulfonic acid, Indigotrisulfonic acid, Indigomono, Phenosafranin, Safranin T, Neutral red, ferrate, cuprous cyanide, metallocyanide, metal hydride, and quinone. Oxygen/air cathodes with an acid or base electroltye may also be used.
If cathode 30 is an air cathode, it may be a decoupled air cathode including an ORR component and an OER component, with the ORR component and OER component physically separate, as well as an acidic catholyte
Battery 10 further includes an aqueous alkali metal ion anolyte 40. If the anode active material contains an alkali metal, then the alkali metal in the anolyte is a different alkali metal than in the anode active material.
Battery 10 also includes a catholyte 50, which may include an alkali metal ion catholyte or a metal-acid catholyte. The alkali metal ion in an alkali metal ion catholyte 50 is the same as that in anolyte 40. Battery 10 further includes mediator-ion solid state electrolyte 60, containing the same alkali metal ion as anolyte 40 and catholyte 50. Mediator-ion solid state electrolyte 60 exchanges the alkali metal ion with anolyte 40 and catholyte 50 as needed to maintain charge balance, providing ionic channels between the anode side of the battery and the cathode side of the battery. Mediator-ion solid state electrolyte 60 also substantially blocks the flow of liquid between the anode side of battery 10 and the cathode side of battery 10, but also contains ion channels that allow the mediator ion to pass through. As a result, anolyte 40 and catholyte 50 cannot directly chemically react with one another. Catholyte 50 also cannot reach and directly chemically react with the anode active material. Anolyte 40 cannot reach and directly react with the cathode active material. All, or at least 99.9% of such potential direct chemical reactions may be prevented by the mediator-ion solid state electrolyte 60 during normal operation of battery 10. Mediator-ion solid state electrolyte 60 may further prevent dendrites from reaching cathode 30. Suitable mediator-ion solid state electrolytes 60 include those containing the alkali metal ion of interest that are stable in the presence of water, such as Na3−4 Sc2(PO4)2.6(SiO4)0.4 (NSP), Na3Zr2Si2PO12 (NZSP), Li1+x+y AlxTi2−xP3−ySiyO12 (LATP) and other Li+-ion or Na+-ion solid state electrolytes.
Battery 10, when in use, may be connected to external circuit 70, which allows the flow of electrons between anode 20 and cathode 30. External circuit 70 may include an external device 80. External device 80 may be something powered by battery 10 if the battery is being discharged. External device 80 may be an energy source, such as an AC electricity source, if battery 10 is being charged.
More particularly, during discharge, zinc in the metallic zinc anode 20a is first oxidized by losing two electrons to the external circuit 70 to create a zinc cation (Zn2+) that reacts with negatively charged hydroxide (OHF) ions to form soluble zincate ions. The zincate has a tendency to dissociate into insoluble zinc oxide and water upon being saturated in an aqueous solution. At cathode 30a during discharge, the liquid bromine accepts an electron provided by external circuit 70 and is reduced to bromide ion (Br−). To maintain charge balance between the anolyte 40a and catholyte 50a, the lithium ion or sodium ion, migrates through the NSP, NZSP, or LATP solid state electrolyte 60a. Once present in catholyte 50a, the lithium ion or sodium ion reacts with bromine ion to form the alkali metal ion bromide.
During charge, zincate in anolyte 40a accepts electrons from the external circuit 70 and is reduced into metallic zinc, which plates onto anode 20a and hydroxide ions, which remain in anolyte 40a. The hydroxide ions associate with lithium ion or sodium ion in the solution and form lithium hydroxide or sodium hydroxide. The bromine ion is oxidized to liquid bromine, freeing the lithium ion or sodium ion. To maintain charge balance between the anolyte 40a and catholyte 50a, the lithium ion or sodium ion, migrates the opposite way through the NSP, NZSP, or LATP solid state electrolyte 60a.
Further details of specific ZnBr2 batteries are provided in the Example 1 and in
More particularly, during discharge, iron in the metallic iron anode 20b is first oxidized by losing two electrons to the external circuit 70 to create an iron cation (Fe2+) that reacts with negatively charged hydroxide (OH−) ions to form soluble Fe(OH)2. At cathode 30b during discharge, the ferrocyanide/alkali metal hydroxide catholyte 50b accepts an electron provided by external circuit 70 and the iron in the ferrocyanide is reduced from Fe3+ to Fe2+, forming ferricyanide. To maintain charge balance between the anolyte 40b and catholyte 50b, the lithium ion or sodium ion, migrates through the NSP, NZSP, or LATP solid state electrolyte 60b.
During charge, Fe(OH)2 in anolyte 40b accepts electrons from the external circuit 70 and is reduced into metallic iron, which plates onto anode 20b and hydroxide ions, which remain in anolyte 40b. The hydroxide ions associate with lithium ion or sodium ion in the solution and form lithium hydroxide or sodium hydroxide. The ferricyanide in catholyte 50b is oxidized to ferrocyanide. To maintain charge balance between the anolyte 40b and catholyte 50b, the lithium ion or sodium ion migrates the opposite way through the NSP, NZSP, or LATP solid state electrolyte 60b.
Further details of specific Fe-ferrocyanide batteries are provided in the Example 3 and in
More particularly, during discharge, iron in the metallic iron anode 20c is first oxidized by losing two electrons to the external circuit 70 to create an iron cation (Fe2+) that reacts with negatively charged hydroxide (OHF) ions to form soluble Fe(OH)2. At cathode 30c during discharge, the catholyte 50c accepts an electron provided by external circuit 70 and OER 90 catalyzes the formation of H3PO4 and the release of O2 and M+ from MH2PO4. To maintain charge balance between the anolyte 40c and catholyte 50c, the lithium ion or sodium ion, migrates through the NSP, NZSP, or LATP solid state electrolyte 60c.
During charge, Fe(OH)2 in anolyte 40c accepts electrons from the external circuit 70 and is reduced into metallic iron, which plates onto anode 20c and hydroxide ions, which remain in anolyte 40c. The hydroxide ions associate with lithium ion or sodium ion in the solution and form lithium hydroxide or sodium hydroxide. At cathode 30c during charge, the catholyte 50c release an electron to external circuit 70 and OPR 100 catalyzes the formation of MH2PO4 from H3PO4, O2 and M+. To maintain charge balance between the anolyte 40c and catholyte 50c, the lithium ion or sodium ion migrates the opposite way through the NSP, NZSP, or LATP solid state electrolyte 60c.
OER 90 contains an OER catalyst, which is typically different than the ORR catalyst, found in ORR 100. Cathode 30c is a decoupled air cathode, containing a separate ORR 100 and OER 90, because the active sites for the ORR and the OER and the electrochemical environment in which the reactions occur are so different that it is very difficult to achieve high activity for both reactions within one material. For example, the ORR typically uses hydrophobic sites, which form a three-phase (solid catalyst, liquid electrolyte, and air) interface. In contrast, the OER typically uses hydrophilic sites to maximize the contact between the catalyst and the electrolyte. By dividing the OER and ORR functions into two different physical components 90 and 100 of the decoupled air cathode 30c, which may be two different electrodes, the two different physical components 90 and 100 may be optimized for OER and ORR respectively. This allows high battery efficiency as well as long cycle life. Alternative air cathode designs, with or without a separate ORR and OER may also be used, but the configuration of
OER 90 may include any OER catalyst able to evolve oxygen from catholyte 50c into the air. The exact identity of the OER catalyst as well as the location of OER 90 in battery 10c may depend somewhat on what constitutes catholyte 50c. For instance, the OER catalyst may have a set stability, activity, or both in a solution with the catholyte's acidity. Any support, particularly conductive supports, may have less than a set chemical reactivity with catholyte 50c and may have a set stability at the catholyte's acidity. Any support may also have low or no OER activity, particularly as compared to the OER catalyst. Example OER catalysts include iridium oxide (IrO2), which may be in the form or a thin film grown on a titanium (Ti) mesh (IrO2/Ti). Other materials like MnOx, PbO2, and their derivatives are also suitable OER catalysts. Other OER catalysts may be free-standing, or on different conductive supports, such as other metal meshes. The OER catalyst may be present in small particles, such as particles less than 100 nm, less than 50 nm, or less than 20 nm in average diameter. In order to present a high number of active sites to the catholyte, the OER catalyst may be amorphous. OER 90 may be carbon-free and binder-free, ensuring good mechanical integrity in battery 10c.
ORR 100 may include any ORR catalyst able to reduce oxygen in the air so that it may react with catholyte 50c. The exact identity of the ORR catalyst as well as the location of ORR 100 may depend somewhat on what constitutes catholyte 50c. Example ORR catalysts include a noble-metal-based catalyst, such as platinum (Pt), palladium (Pd), silver (Ag), and their alloys or non-noble-metal-based catalysts such as cobalt-polypyrrole (Co-PPY-C), iron/nitrogen/carbon(Fe/N/C), or pure carbon with hetero-atom dopants, such as nitrogen (N)-doped graphene, carbon nanotube, or mesoporous carbon. Because it is decoupled from OER 90, ORR 100 may be isolated during a high-voltage charge process, minimizing catalyst dissolution and oxidation.
In order to allow access to air, at least a portion of decoupled air cathode 30c, such as at least ORR 100 may be porous. OER 90 may also be porous.
Further details of specific Fe-air batteries are provided in the Example 4 and in
More particularly, during discharge, zinc in the metallic zinc anode 20d is first oxidized by losing two electrons to the external circuit 70 to create a zinc cation (Zn2+) that reacts with negatively charged hydroxide (OHF) ions to form soluble zincate ions. The zincate has a tendency to dissociate into insoluble zinc oxide and water upon being saturated in an aqueous solution. At cathode 30d during discharge, the catholyte 50d accepts an electron provided by external circuit 70 and the cerium is reduced from Ce4+ to Ce3+. To maintain charge balance between the anolyte 40d and catholyte 50d, the lithium ion or sodium ion, migrates through the NSP, NZSP, or LATP solid state electrolyte 60d.
During charge, zincate in anolyte 40d accepts electrons from the external circuit 70 and is reduced into metallic zinc, which plates onto anode 20d, and hydroxide ions, which remain in anolyte 40d. The hydroxide ions associate with lithium ion or sodium ion in the solution and form lithium hydroxide or sodium hydroxide. The cerium in catholyte 50d is oxidized from Ce3+ to Ce4+. To maintain charge balance between the anolyte 40d and catholyte 50d, the lithium ion or sodium ion migrates the opposite way through the NSP, NZSP, or LATP solid state electrolyte 60d.
Further details of specific Zn-metal acid batteries are provided in the Example 5 and in
A battery according to the present disclosure, particularly a Zn—Br2 battery, a Zn-ferrocyanide battery, a Fe-ferrocyanide battery, a Zn-air battery, a Fe-air battery, a Zn-metal acid battery, or a Fe-metal acid battery may have of the following features alone or in combination:
A rechargeable battery as disclosed herein may be in traditional form, such as a coin cell or jelly roll, or a more complex cell such as a prismatic cell. It may include a single electrochemical cell or multiple cells. Batteries with more than one cell may contain components to connect or regulate these multiple electrochemical cells.
In the case of more sophisticated batteries, they may contain more complex components, such as safety devices to prevent hazards if the battery overheats, ruptures, or short circuits. Particularly complex batteries may also contain electronics, storage media, processors, software encoded on computer readable media, and other complex regulatory components.
Rechargeable batteries of the present disclosure may be used in a variety of applications. They may be in the form of standard battery size formats usable by a consumer interchangeably in a variety of devices. They may be in power packs, for instance for tools and appliances. They may be usable in consumer electronics including cameras, cell phones, gaming devices, or laptop computers. They may also be usable in much larger devices, such as electric automobiles, motorcycles, buses, delivery trucks, trains, or boats. Furthermore, batteries according to the present disclosure may have industrial uses, such as energy storage in connection with energy production, for instance in a smart grid, or in energy storage for factories or health care facilities, for example in the place of generators.
Voltages herein are given versus a standard hydrogen electrode.
The present invention may be better understood through reference to the following examples. These examples are included to describe exemplary embodiments only and should not be interpreted to encompass the entire breadth of the invention.
Two Zn—Br2 batteries as shown in
The Zn—Br2 batteries were assembled and tested in a layered battery format. The anode was formed by attaching a Zn metal plate to a titanium wire external circuit. The cathode was formed by attaching a carbon paper matrix (Toray, Japan) to a titanium wire external circuit.
For the Zn(NaOH)∥Na-SSE∥Br2 (NaBr) cell, the anolyte and the catholyte were, respectively, 0.5 M NaOH aqueous solution and 0.5 M NaBr+0.1 M Br2 aqueous solution.
For the Zn(LiOH)∥Li-SSE∥Br2 (LiBr) cell, the anolyte and the catholyte were, re-spectively, 0.5 M LiOH aqueous solution and 0.5 M LiBr+0.1 M Br2 aqueous solution.
The NSP solid state electrolyte was prepared by a solid-state reaction, followed by a spark plasma sintering (SPS) process. In particular the NSP solid state electrolyte was prepared by a sequence of solid-state reactions of stoichiometric mixtures of Na2CO3, Sc2O3, (NH4)2H(PO4)3, and SiO2. The mixtures were ground together for 1 h in an agate mortar and heated first at 450° C. for 1.5 h and then at 900° C. for 24 h in air with a heating rate of 3° C./min from 450° C. to 900° C. The heated mixture was then ball-milled for 8 h, pressed into pellets in a graphite die, and sintered by a SPS process at 1200° C. for 10 min with a heating rate of 80° C./min under a pressure of 50 MPa.
The LATP solid state electrolyte was purchased from Ohara Corporation (Japan) (Na+-ion conductivity of 1×10−4 S/cm).
The morphologies of the cathode carbon paper matrix and the NSP solid state electrolyte were studied with a Quanta 650 SEM. The fibrous structure of the cathode carbon paper is evident in
As shown in
Charge-discharge curves as well as the polarization behavior of the Zn— Br2 cells were recorded with an Arbin BT 2000 battery cycler.
Polarization behavior of the Zn(NaOH)∥Na-SSE∥Br2 (NaBr) cell and the Zn(LiOH)∥Li-SSE∥Br2 (LiBr) cell was also studied. The OCVs of the two cells were almost identical at 2.2-2.3 V. Upon the application of discharge and charge currents, the voltage responses of the two cells were recorded. As seen in
Compared to the Zn(NaOH)∥Na-SSE∥Br2 (NaBr) cell, the relatively higher polarization behavior of the Zn(LiOH)∥Li-SSE∥Br2 (LiBr) cell was attributed primarily to the relatively lower ionic conductivity of LATP (1×10−4 S/cm) as compared to NSP (3.4×10−4 S/cm) and the lower dissociation behavior of LiOH in aqueous solution.
To demonstrate the ability of batteries of the present disclosure to use a variety of cathode active materials, Zn-ferrocyanide (K4Fe(CN)6) batteries with either a LATP or NSP solid state electrolyte was formed. The batteries also demonstrated that the catholyte and anolyte may share more chemical components other than the mediator-ion (in this case LiOH, or NaOH was shared).
The Zn(LiOH)∥Li-SSE∥LiOH/(K4Fe(CN)6) cell was prepared with a 0.5 M LiOH anolyte and a mixture of 0.4 M K4[Fe(CN)6]+0.5 M LiOH as the catholyte. The Zn(LiOH)∥Na-SSE∥NaOH/(K4Fe(CN)6) cell with the Na+-ion solid state electrolyte was prepared with a 0.5 M NaOH anode electrolyte and a mixture of 0.4 M K4[Fe(CN)6]+0.5 M NaOH as the catholyte. Polarization behavior of the two cells is provided in
A Fe-ferrocyanide battery as shown in
Two Fe-air batteries as shown in
The anodes were synthesized carbon nanofiber (CNF) supported iron oxide (Fe2O3/CNF). The XRD pattern of the Fe2O3/CNF (
The SSE two types of solid electrolytes employed here are, respectively, LATP, and Na3Zr2Si2PO12 (NZSP) (421 Energy Corporation, South Korea, with a Na+-ion conductivity of approximately 1.0×10 S/cm at room temperature). The LATP and NZSP did not act as a direct Fe2+-ion conductive media, but provided ionic channels for transporting the mediator Li+-ion or Na+-ion to facilitate charge balance between the anode and cathode sides of the cell during the charge-discharge processes.
Both batteries contained an acidic catholyte, providing a higher positive potential and a theoretical voltage of around 2.11 V. The catholytes contained a H3PO4 solution with either LiH2PO4 or NaH2PO4 as a supporting electrolyte.
The decoupled bifunctional air cathodes contained a titanium mesh supported iridium oxide (IrO2/Ti) electrode as the OER and a carbon-supported platinum (Pt/C) electrode as the ORR.
The loadings of the IrO2 on Ti mesh were estimated to be approximately 0.18 mg/cm2 (1 h deposition), approximately 0.27 mg/cm2 (1.5 h deposition), and approximately 0.36 mg/cm2 (2 h deposition) according to our previous report. However, the influence of the deposition time on the OER activity of the IrO2/Ti electrode was also evaluated. The IrO2 was deposited electrochemicallyusing a 3-electrode cell. Upon applying a constant current to the Ti mesh, the potential of the electrode quickly reaches a stable value at about 0.89 V (
Electrochemical stability of the IrO2/Ti electrode in the H3PO4/NaH2PO4 solution was evaluated by applying a constant current density to the electrode.
The Fe-air batteries had to first be charged before further evaluations were possible, due to the Fe2O3/CNF anode.
As seen in
A Zn-metal acid battery as shown in
Although only exemplary embodiments of the invention are specifically described above, it will be appreciated that modifications and variations of these examples are possible without departing from the spirit and intended scope of the invention. For example, throughout the specification particular measurements are given. It would be understood by one of ordinary skill in the art that in many instances particularly outside of the examples other values similar to, but not exactly the same as the given measurements may be equivalent and may also be encompassed by the present invention.
The present application is a continuation of International Application No. PCT/US2017/037430, filed Jun. 14, 2017; which claims priority to U.S. Provisional Patent Application Ser. No. 62/350,046, filed Jun. 14, 2016, the contents of which are incorporated by reference herein in their entirety.
This invention was made with government support under Grant no. DE-SC0005397 awarded by the Department of Energy. The government has certain rights in the invention.
Number | Date | Country | |
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62350046 | Jun 2016 | US |
Number | Date | Country | |
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Parent | PCT/US2017/037430 | Jun 2017 | US |
Child | 16219301 | US |