阅读说明：本技术 亚铁氰化物溶液的纯化和用途 (Purification and use of ferrocyanide solutions ) 是由 沙洛克·莫塔勒贝 科林·迪恩·维瑟尔 于 2017-12-14 设计创作，主要内容包括：用于有效地纯化用于TMCC最终产品的起始材料的系统和方法,以及用于使用纯化的起始材料有效地产生高品质TMCC材料的系统和方法。(Systems and methods for efficiently purifying starting materials for TMCC end products, and systems and methods for efficiently producing high quality TMCC materials using purified starting materials.)

1. A method of making a Transition Metal Coordination Compound (TMCC) material having good face centered cubic grains and having a crystallite aggregate size greater than 10 microns, comprising:

a) reacting an aqueous solution comprising a ferrocyanide salt and a first amount of a reducing agent with a first amount of an oxidizing agent to produce a purified aqueous solution having a second amount of the reducing agent less than the first amount; and

b) reacting the purified aqueous solution with an aqueous solution comprising a set of transition metal salts to produce the TMCC material.

2. The method of claim 1, wherein the first amount of the oxidizing agent is in a range of 10ppm to 10000 ppm.

3. The method of claim 1, wherein the purified aqueous solution comprises a second amount of the oxidizing agent that is less than the first amount of the oxidizing agent.

4. The method of claim 3, wherein the purified aqueous solution comprises a reduced oxidizing agent.

5. The method of claim 4, wherein the oxidizing agent comprises a first type of oxidizing agent, wherein the reduced oxidizing agent comprises the ferrocyanide salt.

6. The method of claim 5, wherein the first type of oxidant comprises one or more materials selected from the group consisting of potassium ferricyanide, sodium ferricyanide, and combinations thereof.

7. The method of claim 4, wherein the oxidizing agent comprises a second class of oxidizing agent, wherein the reduced oxidizing agent comprises a material that dissipates from the aqueous purification solution prior to the reacting step b.

8. The method of claim 4, wherein the oxidizing agent comprises a third class of oxidizing agent, wherein the reduced oxidizing agent comprises a material that is generally inert in the reacting step b.

9. The method of claim 4, wherein the oxidizing agent comprises a fourth class of oxidizing agent, wherein the reduced oxidizing agent comprises a specific amount of material that declines the reacting step b less than if the specific amount of the reducing agent declined the reacting step b.

10. The method of claim 1, wherein the aqueous solution has a PH in the range of 3-12.

11. The method of claim 1, wherein the purified aqueous solution has a PH in the range of 3-12.

12. The method of claim 1, wherein the aqueous solution and the purified aqueous solution each have a PH in the range of 3-12.

13. The method of claim 1, wherein the oxidizing agent comprises one or more materials selected from hexacyanometallates such as sodium ferricyanide, potassium ferricyanide, and combinations thereof.

14. The method of claim 1, wherein the oxidizing agent comprises one or more materials selected from non-metallic inorganic oxidizing agents that produce one or more of a hypervalent iodine compound, a perchlorate salt, a peroxide, a peroxyacid, and combinations thereof.

15. The process of claim 1, wherein the oxidizing agent comprises one or more materials selected from sulfur-containing compounds, such as sulfur trioxide.

Technical Field

The present invention relates generally to the production of battery components and, more particularly, but not exclusively, to the purification and use of starting materials for Transition Metal Coordination Compound (TMCC) cathode active materials.

Background

It should not be assumed that the subject matter discussed in the background section is prior art only, as it was mentioned in the background section. Similarly, it should not be assumed that the problems mentioned in the background section or relating to the subject matter of the background section have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches that may themselves constitute the invention.

Transition Metal Coordination Compound (TMCC) cathode active materials have been demonstrated to have properties beneficial to many secondary batteries in non-production environments. There are some challenges to producing TMCC cathode active materials on a large industrial scale.

One of those challenges relates to the production of high purity TMCC end products. Starting materials, for example, sodium ferrocyanide, can be used for the production of these TMCC end products. The purity of the starting material may affect the quality of the TMCC end product and affect the process used to prepare the TMCC product.

Some efforts directed to purification may not be reliable in producing high quality TMCC end products. An alternative to purification may include the use of ultra-pure and expensive grades of starting materials. These ultra-pure starting materials can be several to many times more expensive than standard purity and can address some of the issues associated with the production of TMCC end products. Unfortunately, it is not always possible to guarantee ultrapure starting materials for the production of high quality TMCC end products.

Summary of The Invention

Systems and methods for efficiently purifying starting materials for TMCC end products, and for efficiently producing high quality TMCC materials using the purified starting materials, are disclosed.

The above summary of the invention is provided to aid in understanding some technical features related to the purification of starting materials for TMCC production and related to the production of high quality TMCC end products using such purified starting materials, but is not intended to be a complete description of the present invention. A full appreciation of the various aspects of the invention can be gained by taking the entire specification, claims, drawings, and abstract as a whole. The invention may be applicable to other starting materials for TMCC end products than sodium ferrocyanide starting materials, to the production of other materials than TMCC end products, and to the purification of some starting materials.

Embodiments of the present invention may include an oxidation treatment of a ferrocyanide solution used as a precursor in the preparation of a Transition Metal Coordination Compound (TMCC) cathode active material. This oxidative purification process can result in a starting material that allows the formation of good face-centered cubic crystals of TMCC materials. These materials may have crystallite aggregate sizes greater than 10 microns and are therefore easily filtered through a filter media without any clogging of the filter.

Embodiments of the invention may include the formation of good face centered cubic primary crystal structures as well as larger secondary particles and tighter particle size distributions by using such purified precursor materials. The use of these particles of TMCC materials in the electrodes can sometimes lead to increased electrochemical properties.

Embodiments of the purification process for ferrocyanide can have a variety of benefits, including i) a practical, inexpensive, and efficient process that can be scaled up on an industrial scale; and ii) batch-to-batch reproducibility leading to fully controllable particle size generation of the corresponding Transition Metal Coordination Compound (TMCC).

Embodiments of the present invention may include selecting a particular oxidizing agent for use in purifying a starting material comprising an undesirable reducing agent, particularly when the purified starting material is intended for use in a subsequent reaction in which the reducing agent may decline. For example, four classes of oxidizing agents (a ', B', C ', and D') may be used to purify an aqueous solution of starting material a when an undesirable reducing agent is also present in the aqueous solution. These details of these classes of oxidizing agents are highly dependent on the particular starting material and its subsequent use. For example, a 'represents an oxidizing agent that is reduced to a (starting material), B' represents an oxidizing agent that is reduced to B (material that dissipates from the starting material), C 'represents an oxidizing agent that is reduced to C (which is still present in solution, but is inert in subsequent reactions), and D' represents an oxidizing agent that is reduced to D (which is still present in solution and negatively affects subsequent reactions to a lesser extent than the reducing agent).

A process for making a Transition Metal Coordination Compound (TMCC) material having good face centered cubic grains and having a crystallite aggregate size greater than 10 microns includes a) reacting an aqueous solution comprising a ferrocyanide salt and a first amount of a reducing agent with a first amount of an oxidizing agent to produce a purified aqueous solution having a second amount of the reducing agent less than the first amount; and b) reacting the purified aqueous solution with an aqueous solution comprising a set of transition metal salts to produce a TMCC material.

The oxidizing agent may comprise one or more materials selected from the group consisting of: chromates such as anhydrous sodium dichromate, higher iodine such as sodium periodate, hypochlorites such as sodium hypochlorite, osmium such as osmium tetroxide, perchlorates such as sodium perchlorate hydrate, peroxides such as hydrogen peroxide, peroxy acids and salts such as peracetic acid and ammonium persulfate, potassium hydrogen persulfate, potassium nitrosodisulfonate, potassium peroxodisulfate, potassium persulfate, sodium persulfate, sulfur trioxide-sulfur trioxide complexes, potassium ferricyanide, sodium ferricyanide, bromine, chlorine, iodine, trimethylamine-N-oxide, tetrapropylammonium perruthenate, potassium perruthenate, tetracyanoethylene, TEMPO, sodium phosphomolybdate, sodium permanganate, sodium percarbonate, sodium dichloroisocyanurate, selenium dioxide, potassium permanganate, phosphorus oxychloride, phosphomolybdic acid, oxalyl chloride, oxalyl bromide, nitrosotetrafluoroborate, 4-methylmorpholine N-oxide, methyl chloroacetate, ethyl chloroacetate, n-hydroxytetrachlorophthalimide, 8-ethylquinoline N-oxide, N, N-dichloro-p-toluenesulfonamide, 2, 3-dichloro-5, 6-dicyano-p-benzoquinone, chloramine-T hydrate, ammonium cerium (IV) nitrate, ammonium phosphomolybdate, and combinations thereof.

Any of the embodiments described herein may be used alone or together with one another in any combination. The invention covered in this specification may also include embodiments that are only partially mentioned or implied or that have never been mentioned or implied in this brief summary or in the abstract. While various embodiments of the invention have been suggested by various deficiencies in the art (which may be discussed or suggested at one or more places in the specification), embodiments of the invention do not necessarily address any of these deficiencies. In other words, different embodiments of the invention may address different deficiencies that may be discussed in the present specification. Some embodiments may address only some of the deficiencies, or only one deficiency that may be discussed in the specification, and some embodiments may not address any of these deficiencies.

Other features, benefits and advantages of the invention will be apparent upon review of this disclosure, including the description, drawings and claims.

Drawings

The accompanying figures, in which like reference numerals refer to identical or functionally-similar elements throughout the separate views and which are incorporated in and form a part of the specification, further illustrate the present invention and, together with the detailed description of the invention, serve to explain the principles of the present invention.

FIG. 1 shows a scanning electron micrograph of a control example of a transition metal coordination compound made from a standard ferrocyanide starting material; and

figure 2 shows a scanning electron micrograph of a modified example of a transition metal coordination compound made from an oxidatively purified ferrocyanide starting material.

Detailed Description

Embodiments of the present invention provide systems and methods for efficiently purifying starting materials for TMCC end products, and systems and methods for efficiently producing high quality TMCC materials using purified starting materials. The following description is presented to enable one of ordinary skill in the art to make and use the invention and is provided in the context of a patent application and its requirements.

Various modifications to the preferred embodiments and the generic principles and features described herein will be readily apparent to those skilled in the art. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features described herein.

Definition of

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this general inventive concept belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

The following definitions apply to some aspects described for some embodiments of the invention. These definitions may likewise be extended herein.

As used herein, the term "or" includes "and/or" and the term "and/or" includes any and all combinations of one or more of the associated listed items. Expressions such as "at least one of, when preceding a column of elements, modify the entire column of elements without modifying individual elements of the column.

As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to an object can include a plurality of objects unless explicitly stated otherwise herein.

Furthermore, as also used in the description herein and in the claims that follow, the meaning of "in. It will be understood that when an element is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present.

As used herein, the term "set" refers to a collection of one or more objects. Thus, for example, a group of objects may comprise a single object or a plurality of objects. The objects in a group may also be referred to as members of the group. The objects in a group may be the same or different. In some cases, the objects in a group may share one or more common properties.

As used herein, the term "adjacent" refers to being nearby or contiguous. A nearby object may be spaced apart from another object or may be in actual or direct contact with another object. In some cases, an adjacent object may be coupled with another object, or may be integrally formed with another object.

As used herein, the terms "connected", and "connecting" refer to direct attachment or linkage. The joined objects have no or substantially no intervening object or group of objects, as referred to herein.

As used herein, the terms "coupled", and "coupling" refer to an operative connection or link. An attached object may be directly connected to another object, or may be indirectly connected to another object, such as via an intervening set of objects.

The use of the term "about" applies to all numerical values, whether explicitly stated or not. The term generally refers to a range of numerical values that one of ordinary skill in the art would consider reasonably inaccurate (i.e., having equivalent functionality or result) of the recited value. For example, the numerical values can be considered to include a deviation of ± 10% of a given numerical value, provided that such deviation does not alter the ultimate function or result of the value. Thus, a value of about 1% may be interpreted as a range of 0.9% to 1.1%.

As used herein, the terms "substantially" and "substantial" refer to a degree or range of merit consideration. When used in conjunction with an event or circumstance, the term can refer to the situation in which the event or circumstance occurs precisely as well as the situation in which the event or circumstance occurs approximately, such as resulting from typical tolerance levels or variations in the embodiments described herein.

As used herein, the terms "optional" and "optionally" mean that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

As used herein, the term "dimension" refers to a characteristic dimension of an object. Thus, for example, the size of an object that is spherical may refer to the diameter of the object. For an aspheric object, the size of the aspheric object can refer to the diameter of the corresponding spherical object that exhibits or has a particular set of derivable or measurable properties (substantially the same as the properties of the aspheric object). Thus, for example, the size of an aspherical object may refer to the diameter of a corresponding spherical object that exhibits light scattering or other properties substantially the same as the properties of the aspherical object. Alternatively or in combination, the size of the non-spherical object may refer to an average of various orthogonal dimensions of the object. Thus, for example, the size of a spheroidal object may refer to the average of the major and minor axes of the object. When a group of objects is referred to as having a particular size, it is contemplated that the objects may have a size distribution around the particular size. Thus, as used herein, the size of a group of objects may refer to a typical size of a size distribution, such as an average size, a median size, or a peak size.

The manufacturing process for TMCC electrode materials comprises using an aqueous solution of a ferrocyanide salt (e.g. sodium ferrocyanide) as starting material. The presence of any type of residual reducing agent in the starting material is generally detrimental to the quality of the final product. Large-scale manufacture of high quality TMCC materials requires large amounts of starting materials. Any method or system that efficiently and cost-effectively provides large amounts of appropriately purified starting materials would provide many benefits to manufacturers and consumers of these TMCC materials.

Many attempts to purify different grades of commercially available sodium ferrocyanide failed to produce high quality TMCC end products. For example, purification by crystallization and/or ion exchange treatment of sodium ferrocyanide solutions yields unsatisfactory results. These unsatisfactory results may include the formation of materials that are difficult to filter and the formation of crystalline/aggregate structures that are malformed and therefore exhibit poor electrochemical performance.

It is possible to obtain sodium ferrocyanide solution in ultrapure form at a significant additional cost. The use of such an ultrapure form can provide a number of benefits, for example, improvements in filtration. However, the crystal/aggregate structure may still be misshapen and result in a material that exhibits poor electrochemical performance. Thus, the additional cost of the ultrapure starting material does not provide sufficient benefit to match the expense.

It is speculated that certain starting material solutions may have an increased/extended shelf life when they contain a reducing agent in the solution. While some purification schemes can more routinely address other types of impurities, purification fails to have the intended results when they do not address the removal of reducing agents and when those reducing agents may interfere with the intended use of the purified starting material.

In one example of an embodiment of the present invention, the oxidative treatment of the sodium ferrocyanide solution comprises adding a small amount of about 10ppm to about 10000ppm of an oxidizing agent. This step may lead to the neutralization of the reducing agent, which may be present in the sodium ferrocyanide as an impurity or additive.

More broadly, the present invention relates to a simple and cost-effective process for the purification of ferrocyanide by simply adding a small amount of an oxidizing agent to a sodium ferrocyanide solution. Furthermore, the use of purified starting materials results in a high quality TMCC electrode material. The method and system thus produce excellent results efficiently and cost-effectively.

Another contribution to effectiveness and cost effectiveness is that the purified solution can be used in subsequent manufacturing steps without further processing to produce high quality TMCC materials.

General formula (Na)₂X^IIFe^III[Fe^II(CN)₆].nH₂O), a crystal structure material with an open framework, is a promising cathode material for rechargeable sodium-ion batteries.

Such cathode materials are typically prepared by adding a mixed solution of iron (iii) and another metal ion to an aqueous ferrocyanide solution.

The reaction can also be carried out by a coprecipitation method in which the particle morphology is adjusted by the addition time, stirring rate, concentration and temperature.

Due to the insolubility of these pigments, the rapid deposition of the particles in the reaction medium leads to the formation of very small nanoparticles of granular, not completely defined crystalline structure. These nanoparticles are very difficult to filter, so their isolation represents a major challenge on an industrial scale. In addition, these particle-shaped nanoparticles exhibit poor electrochemical performance compared to fully face-centered cubic crystalline particles.

The present invention relates to the purification of aqueous solutions of ferrocyanide salt, which is one of the starting materials for the preparation of TMCC cathode materials. Oxidative purification of ferrocyanide salt solutions and their use in the immediate subsequent TMCC manufacturing step leads to the production of high quality TMCC materials. The materials thus obtained are easy to filter and their electrochemical properties are significantly improved.

Experimental part

Example 1 control

In a 2 l jacketed reactor, 114g of water were added and heated to 80 ℃ with stirring. Solutions a and B were added simultaneously under a stream of nitrogen over a period of 2.0 hours.

The mixture was heated at 75 ℃ for an additional 1 hour, then cooled to 20 ℃ and filtered (filter paper size 11 microns). The filter cake was washed with 300g of water and dried under vacuum at 80 ℃ to give 100g of a dark blue powder.

Filtration was very slow and the total filtration time and wash time was about 4.0 hours.

Solution A: the solution was prepared by dissolving 47.0g of manganese sulfate monohydrate and 20.0g of iron (III) sulfate hydrate in 137g of water.

Solution B: this solution was prepared by dissolving 130g of sodium ferrocyanide decahydrate in 405g of water.

Figure 1 shows a scanning electron micrograph of a control example of a transition metal complex made from a standard ferrocyanide starting material. The morphology and size of these particles was confirmed in scanning electron micrographs. Scanning electron microscopy showed that the particles in the form of particles had an average size of <100 nm.