阅读说明：本技术 作为锂电池组的阳极电解质的聚酰胺、聚脲和聚磷酰胺 (Polyamides, polyureas and polyphosphamides as anode electrolytes for lithium batteries ) 是由 S.R.比米雷迪 H.B.埃托尼 于 2020-03-09 设计创作，主要内容包括：本发明涉及作为锂电池组的阳极电解质的聚酰胺、聚脲和聚磷酰胺。已经合成了基于聚酰胺、基于聚脲和基于聚磷酰胺的新型聚合物。当这些聚合物与电解质盐组合时,这样的聚合物电解质作为锂电池组电池中的阳极电解质具有优异的电化学稳定性。(The present invention relates to polyamides, polyureas and polyphosphates as anode electrolytes for lithium batteries. Novel polymers based on polyamides, on polyureas and on polyphosphates have been synthesized. When these polymers are combined with electrolyte salts, such polymer electrolytes have excellent electrochemical stability as an anode electrolyte in lithium battery cells.)

1. A polymer comprising a polymer structure as described below:

wherein:

each R is independently selected from alkyl and/or aryl substituents; and

a and n are integers, wherein a ranges from 1 to 10 and n ranges from 1 to 1000.

2. The polymer of claim 1, further comprising an electrolyte salt, wherein the polymer is an electrolyte.

3. The polymer of claim 2, further comprising ceramic electrolyte particles.

4. The polymer of claim 1, wherein the polymer is crosslinked.

5. The polymer of claim 4, further comprising an electrolyte salt, wherein the polymer is an electrolyte.

6. A polymer comprising a polymer structure as described below:

wherein:

each R is independently selected from alkyl and/or aryl substituents; and

a and n are integers, wherein a ranges from 1 to 10 and n ranges from 1 to 1000.

7. The polymer of claim 6, further comprising an electrolyte salt, wherein the polymer is an electrolyte.

8. The polymer of claim 7, further comprising ceramic electrolyte particles.

9. The polymer of claim 6, wherein the polymer is crosslinked.

10. The polymer of claim 9, further comprising an electrolyte salt, wherein the polymer is an electrolyte.

11. A polymer comprising a polymer structure as described below:

wherein:

each R is independently selected from alkyl and/or aryl substituents; and

a and n are integers, wherein a ranges from 1 to 10 and n ranges from 1 to 1000.

12. The polymer of claim 11, further comprising an electrolyte salt, wherein the polymer is an electrolyte.

13. The polymer of claim 12, further comprising ceramic electrolyte particles.

14. The polymer of claim 11, wherein the polymer is crosslinked.

15. The polymer of claim 14, further comprising an electrolyte salt, wherein the polymer is an electrolyte.

16. A polymer comprising a polymer structure as described below:

wherein:

each R is independently selected from alkyl and/or aryl substituents; and

a and n are integers, wherein a ranges from 1 to 10 and n ranges from 1 to 1000.

17. The polymer of claim 16, further comprising an electrolyte salt, wherein the polymer is an electrolyte.

18. The polymer of claim 17, further comprising ceramic electrolyte particles.

19. The polymer of claim 16, wherein the polymer is crosslinked.

20. The polymer of claim 19, further comprising an electrolyte salt, wherein the polymer is an electrolyte.

21. An electrochemical cell, comprising:

an anode configured to absorb and release lithium ions;

a cathode comprising cathode active material particles, an electron conducting additive, and a catholyte;

a current collector adjacent to an outer surface of the cathode; and

a separator region between an anode and a cathode, the separator region comprising the electrolyte of claim 7 or claim 17, and the electrolyte salt being a lithium salt.

22. The electrochemical cell of claim 21, wherein the separator region comprises two layers: an anolyte layer adjacent the anode, the anolyte layer comprising an anolyte; and a separator electrolyte layer between the anolyte layer and the cathode, the separator electrolyte layer comprising a separator electrolyte, wherein the anolyte comprises the electrolyte of claim 7 or claim 17.

23. The electrochemical cell of claim 22, wherein the separator electrolyte comprises a solid polymer electrolyte.

24. The electrochemical cell of claim 22, wherein at least one of the anode electrolyte and the separator electrolyte further comprises ceramic electrolyte particles.

25. The electrochemical cell of claim 22, wherein at least one of the anode electrolyte and the separator electrolyte is crosslinked.

26. The electrochemical cell of claim 21, wherein the anode comprises a solid metal membrane made of a material selected from the group consisting of lithium metal and lithium alloys.

27. The electrochemical cell of claim 21, wherein the anode comprises anode active material particles selected from the group consisting of lithium titanate, graphite, silicon, and combinations thereof, wherein the anode further comprises the electrolyte of claim 7 or claim 17.

Technical Field

The present invention relates generally to electrolytes for lithium batteries, and more particularly to electrolytes particularly suited for use with anodes.

Background

Efforts are underway to improve the performance of lithium battery cells by looking at all the components in such cells and looking for ways to improve performance and avoid degradation.

Polymer electrolytes are of great interest in lithium battery cells because of their superior mechanical properties, flexibility and safety characteristics compared to their small molecule counterparts. However, such materials may experience degradation over time under cell operating conditions, particularly in the low potential region of the cell.

Therefore, it would be particularly useful to develop an electrolyte that is particularly stable in the low potential region of a lithium battery cell.

Disclosure of Invention

In one embodiment of the present invention, a polymer having the structure is disclosed.

Each R may be independently selected from any one of alkyl and/or aryl substituents; and a and n are integers, wherein a ranges from 1 to 10 and n ranges from 1 to 1000. In some embodiments of the invention, the polymer further comprises an electrolyte salt, and the polymer is an electrolyte. In some arrangements, the electrolyte also contains ceramic electrolyte particles. In some arrangements, the polymer is crosslinked and may or may not contain an electrolyte salt.

In one embodiment of the present invention, a polymer having the structure is disclosed.

Each R may be independently selected from any one of alkyl and/or aryl substituents; and a and n are integers, wherein a ranges from 1 to 10 and n ranges from 1 to 1000. In some embodiments of the invention, the polymer further comprises an electrolyte salt, and the polymer is an electrolyte. In some arrangements, the electrolyte also contains ceramic electrolyte particles. In some arrangements, the polymer is crosslinked and may or may not contain an electrolyte salt.

In one embodiment of the present invention, a polymer having the structure is disclosed.

Each R may be independently selected from any one of alkyl and/or aryl substituents; and a and n are integers, wherein a ranges from 1 to 10 and n ranges from 1 to 1000. In some embodiments of the invention, the polymer further comprises an electrolyte salt, and the polymer is an electrolyte. In some arrangements, the electrolyte also contains ceramic electrolyte particles. In some arrangements, the polymer is crosslinked and may or may not contain an electrolyte salt.

In one embodiment of the present invention, a polymer having the structure is disclosed.

Each R may be independently selected from any one of alkyl and/or aryl substituents; and a and n are integers, wherein a ranges from 1 to 10 and n ranges from 1 to 1000. In some embodiments of the invention, the polymer further comprises an electrolyte salt, and the polymer is an electrolyte. In some arrangements, the electrolyte also contains ceramic electrolyte particles. In some arrangements, the polymer is crosslinked and may or may not contain an electrolyte salt.

In one embodiment of the present invention, an electrochemical cell is disclosed. The electrochemical cell includes at least an anode configured to absorb and release lithium ions; a cathode comprising cathode active material particles, an electron conducting additive, and a catholyte; a current collector adjacent to an outer surface of the cathode; and a separator region located between the anode and the cathode, the separator region comprising any polymer electrolyte disclosed herein, i.e., any polymer disclosed herein and an electrolyte salt, such as a lithium salt.

In some arrangements, the separator region in the electrochemical cell has at least two layers: an anolyte layer adjacent the anode, the anolyte layer comprising an anolyte; and a separator electrolyte layer located between the anolyte layer and the cathode, the separator electrolyte layer comprising a separator electrolyte. The anolyte may comprise any of the polymers and electrolyte salts disclosed herein, such as lithium salts. In some arrangements, the separator electrolyte contains a solid polymer electrolyte suitable for use in a lithium electrochemical cell. In some arrangements, at least one of the anolyte and the separator electrolyte further comprises ceramic electrolyte particles. In some arrangements, at least one of the anolyte and the separator electrolyte is crosslinked. In some arrangements, the anode contains a solid metal film made of a material such as lithium metal and/or a lithium alloy. In some arrangements, the anode contains anode active material particles, such as lithium titanate, graphite, silicon, and combinations thereof, in which case the anode may also contain any of the polymer electrolytes disclosed herein.

Brief Description of Drawings

The foregoing aspects and others will become readily apparent to those skilled in the art from the following description of the illustrative embodiments, when read in light of the accompanying drawings.

Fig. 1 is a graph showing differential pulse voltammetry data for a model compound dimethylacetamide according to one embodiment of the present invention.

FIG. 2 is a graph showing differential pulse voltammetry data for a model compound, N' -dimethylpropyleneurea, according to an embodiment of the invention.

Figure 3 is a graph showing differential pulse voltammetry data for a model compound, hexamethylphosphoramide, according to one embodiment of the present invention.

Fig. 4 is a schematic diagram of a configuration of a lithium battery cell according to an embodiment of the present invention.

Fig. 5 is a schematic view of another configuration of a lithium battery cell according to another embodiment of the present invention.

Detailed Description

Embodiments of the invention are illustrated in the context of polymers that can be used as electrolytes or electrolyte additives in lithium battery cells and the like. However, those skilled in the art will readily appreciate that the materials and methods disclosed herein will have application in many other situations where a low potential electrolyte is desired, particularly where long term stability is important.

These and other objects and advantages of the present invention will become more fully apparent from the following description taken in conjunction with the accompanying drawings.

All publications cited herein are incorporated by reference in their entirety for all purposes as if fully set forth herein.

In the present disclosure, the terms "negative electrode" and "anode" are both used to describe a negative electrode. Likewise, the terms "positive electrode" and "cathode" are both used to describe a positive electrode. The term "anolyte" is used to describe any electrolyte within or adjacent to the anode. The term "catholyte" is used to describe any electrolyte within or adjacent to the cathode.

It should be understood that the terms "lithium metal" or "lithium foil" as used herein with respect to the negative electrode describe both pure lithium metal and lithium-rich metal alloys known in the art. Examples of lithium-rich metal alloys suitable for use as the anode include Li-Al, Li-Si, Li-Sn, Li-Hg, Li-Zn, Li-Pb, Li-C, or any other Li-metal alloy suitable for use in a lithium metal battery. Other negative electrode materials that may be used in embodiments of the invention include particulate materials into which lithium may be intercalated, such as graphite, as well as other materials that can absorb and release lithium ions, such as silicon, germanium, tin, and alloys thereof. In addition to the particulate negative electrode material, such anodes include an anolyte and optionally a binder. Many of the embodiments described herein relate to batteries having a solid polymer electrolyte that functions as both an electrolyte and a separator. As is well known in the art, batteries with liquid electrolytes use inactive separator materials other than liquid electrolytes.

The following sentence structure is used throughout this disclosure: "each variable is independently selected from" the provided list. Examples of such uses can be found with reference to X groups in some of the polymer structures of the present invention in which a plurality of X's are present. Examples are "each X may be independently selected from hydrogen, fluoro, methyl, ethyl, isopropyl and trifluoromethyl. "this statement structure is used to indicate that for a particular X in the structure, any of the groups in the list can be used. In selecting a group for another X in the structure, any of the groups in the list can be used without regard to the selections already made for other X groups. Thus, the following arrangements are possible: all xs may be the same, all xs may be different, or some xs may be the same and some may be different.

The molecular weights given herein are number average molecular weights.

The term "solid polymer electrolyte" is used herein to refer to a polymer electrolyte that is solid at the operating temperature of the battery cell. Examples of useful battery cell operating temperatures include room temperature (25 ℃), 40 ℃, and 80 ℃.

In this disclosure, ranges of values are given for a number of variables. It should be understood that possible values for any variable also include any range included within the given range.

Polyamide, polyurea and polyphosphazene polymers

In various embodiments of the present invention, polyamide-based, polyurea-based, and polyphosphazene-based polymers are disclosed. Such polymers may be mixed with lithium salts and used as an anode electrolyte in lithium batteries. Such polymer electrolytes have improved anode stability compared to conventional polymer electrolytes.

In some embodiments of the invention, the general structure of the polyamide-based polymer is as follows:

wherein each R is independent of the other R and may be an alkyl and/or aryl substituent. a and n are integers. The value of a ranges from 1 to 10. The value of n ranges from 1 to 1000.

In some embodiments of the invention, the general structure of the polyurea-based polymer is as follows:

wherein each R is independent of the other R and may be an alkyl and/or aryl substituent. a and n are integers. The value of a ranges from 1 to 10. The value of n ranges from 1 to 1000.

In some embodiments of the invention, the general structure of the phosphate-based polymer is as follows:

wherein each R is independent of the other R and may be an alkyl and/or aryl substituent. a and n are integers. The value of a ranges from 1 to 10. The value of n ranges from 1 to 1000.

In some embodiments of the invention, the generic structure of the polyphosphazene based polymer is as follows:

wherein each R is independent of the other R and may be an alkyl and/or aryl substituent. a and n are integers. The value of a ranges from 1 to 10. The value of n ranges from 1 to 1000.

In some embodiments of the invention, particles of ceramic electrolyte are mixed into any of the polymer electrolytes disclosed herein to form an enhanced composite electrolyte with excellent ion transport and mechanical properties. Such composite electrolytes are useful as anode electrolytes in lithium battery cells. Examples of ceramic electrolytes that can be used in admixture with the polymer electrolyte include, but are not limited to, those shown in table 1 below.

Table 2 below shows the lithium ion transport properties of various polymer anode electrolyte materials. These polymers exhibit promising lithium ion transport properties.

Electrochemical stability

The high reduction stability of some of the polymer electrolytes disclosed herein is approximated by Differential Pulse Voltammetry (DPV) using their respective small molecules as a model system. Model small molecules of polybutyl N, N-dimethylurea (compound 1), polyhexamethyl N, N' -dimethyldiamidomethyl phosphate (compound 2), and polyhexamethyl tetramethylphosphoramide (compound 3) are shown below as polyamide (1), polyurea (2), and polyphosphamide (3), respectively.

DPV was measured using a three-electrode system comprising a Pt button electrode, a Pt wire counter electrode and a quasi-reference electrode consisting of 10mM AgNO immersed in a 0.1M tetrabutylammonium hexafluorophosphate solution in a glass tube with Vycor frit attached₃Is composed of Ag wires. First in a 0.1M tetrabutylammonium perchlorate (TBACLO)₄) Was calibrated to the quasi-reference electrode with 10mM ferrocene in THF solution. Para 0.1M Polybutyl N, N-dimethyl Urea (Compound 1), Polyhexyl N, N' -dimethylMethyl ester of bisamido phosphate (Compound 2) and polyhexamethylene tetramethyl phosphoramide (Compound 3) at 0.1M TBACLO₄The solution in THF of (1) was subjected to DPV at a scan rate of 5 mV/s. The DPV data were then normalized to Li/Li + to test the reduction stability of the electrolyte materials with respect to lithium when they interacted with the lithium anode in an actual lithium metal battery cell.

The voltage stability of dimethylacetamide was inferred by measuring the voltage stability of polyamide, and the results are shown in the graph of fig. 1. The voltage stability of N, N' -dimethylpropyleneurea (1) was inferred by measuring the voltage stability of the polyurea, and the results are shown in the graph of fig. 2. The voltage stability of hexamethylphosphoramide (2) was inferred by measuring the voltage stability of polyphosphamide (3), and the results are shown in the graph of fig. 3. As shown in fig. 1,2 and 3, the three model compounds 1,2 and 3 showed electrochemical reduction stability up to 0.4V. This clearly shows that these types of amide-, urea-and phosphoramide-based structural systems are reductively stable and very promising candidates for use as high energy density lithium ion battery anode electrolytes.

Battery design comprising polyamide-based, polyurea-based and polyphosphazene-based polymer electrolytes

In another embodiment of the invention, the lithium battery cell 400 has an anode 420 configured to absorb and release lithium ions, as shown in fig. 4. Anode 420 may be a lithium or lithium alloy foil, or it may be made of a material in which lithium ions can be absorbed, such as graphite or silicon. Other options for anode 420 include, but are not limited to, lithium titanate and lithium silicon alloys. Lithium battery cell 400 also has a cathode 440 that includes cathode active material particles 442, an electronically conductive additive such as carbon black (not shown), a current collector 444, a catholyte 446, and optionally a binder (not shown). A separator electrolyte 460 is present between the anode 420 and the cathode 440. The separator electrolyte 460 facilitates lithium ions moving back and forth between the anode 420 and the cathode 440 as the battery 400 is cycled. The separator electrolyte 460 may include any of the polyamide-based, polyurea-based, and polyphosphazene-based polymer electrolytes disclosed herein.

In another embodiment of the present invention, a battery cell having a second configuration is described. Referring to fig. 5, the lithium battery cell 500 has an anode 520 configured to absorb and release lithium ions. Anode 520 may be a lithium or lithium alloy foil, or it may be made of a material in which lithium ions can be absorbed, such as graphite or silicon. Other options for anode 520 include, but are not limited to, lithium titanate and lithium silicon alloys. The lithium battery cell 500 also has a cathode 550 that includes cathode active material particles 552, an electron conducting additive (not shown), a current collector 554, a catholyte 556, and optionally a binder (not shown). A separator region 560 is present between the anode 520 and the cathode 550. The membrane region 560 contains an anolyte 565 and a membrane electrolyte 558 that facilitate lithium ions moving back and forth between the anode 520 and the cathode 550 as the battery 500 cycles. Anolyte 565 may include any of the polyamide-based, polyurea-based, and polyphosphamide-based polymer electrolytes disclosed herein. In some arrangements, the separator electrolyte 560 contains any electrolyte suitable for use in a lithium battery cell. In some arrangements, the separator electrolyte 560 contains a liquid electrolyte that is immersed in a porous plastic material (not shown). In another arrangement, the separator electrolyte 560 contains a viscous liquid or gel electrolyte. In another arrangement, the separator region 560 contains a solid polymer electrolyte in which the anolyte 565 and/or catholyte 556 are immiscible.

The solid polymer electrolyte used in the separator region, e.g., separator region 460 or 560, or as a catholyte, e.g., catholyte 446 or 556, may be any electrolyte suitable for Li batteries. Of course, many such electrolytes also include electrolyte salt(s) that help provide ionic conductivity. Examples of useful Li salts include, but are not limited to, LiPF₆、LiN(CF₃SO₂)₂(LiTFSI)、Li(CF₃SO₂)₃C、LiN(SO₂CF₂CF₃)₂、LiN(FSO₂)₂、LiN(CN)₂、LiB(CN)₄、LiB(C₂O₄)₂、Li₂B₁₂F_xH_12-x、Li₂B₁₂F₁₂And mixtures thereof. Examples of such electrolytes include, but are not limited to, block copolymers containing an ion conducting block and a structural block, which constitute an ion conducting phase and a structural phase, respectively. The ionically conductive phase may contain one or more linear polymers such as polyethers, polyamines, polyimides, polyamides, polyalkylcarbonates, polynitriles, perfluoropolyethers, fluorocarbon polymers substituted with high dielectric constant groups such as nitriles, carbonates, and sulfones, and combinations thereof. In one configuration, the ionically conductive phase contains one or more phosphorus-based polyester electrolytes as disclosed herein. The linear polymers may also be used in combination with polysiloxanes, polyalkoxysiloxanes, polyphosphazines, polyolefins and/or polydienes as graft copolymers to form the conductive phase. The structural phase may be made of a polymer, such as polystyrene, hydrogenated polystyrene, polymethacrylate, poly (methyl methacrylate), polyvinylpyridine, polyvinylcyclohexane, polyimide, polyamide, polypropylene, polyolefin, poly (t-butyl vinyl ether), poly (cyclohexyl methacrylate), poly (cyclohexyl vinyl ether), poly (t-butyl vinyl ether), polyethylene, poly (phenylene ether), poly (2, 6-dimethyl-1, 4-phenylene ether), poly (phenylene sulfide sulfone), poly (phenylene sulfide ketone), poly (phenylene sulfide amide), polysulfone, a fluorocarbon, such as polyvinylidene fluoride, or a copolymer containing styrene, methacrylate, or vinylpyridine. It is particularly useful if the structural phase is rigid and in a glassy or crystalline state.

With respect to the embodiments described in fig. 4 and 5, suitable cathode active materials include, but are not limited to, LFP (lithium iron phosphate), LMP (lithium metal phosphate, where the metal may be Mn, Co, or Ni), V₂O₅(vanadium pentoxide), NCA (lithium nickel cobalt aluminum oxide), NCM (lithium nickel cobalt manganese oxide), high energy NCM (HE-NCM-magnesium rich lithium nickel cobalt manganese oxide), lithium manganese spinel, lithium nickel manganese spinel, and combinations thereof. Suitable electronically conductive additives include, but are not limited to, carbon black, graphite, vapor grown carbon fibers, graphene, carbon nanotubes, and combinations thereof. Can be bonded togetherThe agent holds the cathode active material particles and the electron conductive additive together. Suitable binders include, but are not limited to, PVDF (polyvinylidene fluoride), PVDF-HFP poly (vinylidene fluoride-co-hexafluoropropylene), PAN (polyacrylonitrile), PAA (polyacrylic acid), PEO (polyethylene oxide), CMC (carboxymethylcellulose), and SBR (styrene-butadiene rubber).

Any of the polymers described herein may be liquid or solid depending on their molecular weight. Any of the polyamide-based, polyurea-based, and polyphosphazene-based polymers described herein can be combined with an electrolyte salt to serve as an electrolyte. Any of the polyamide-based, polyurea-based, and polyphosphazene-based polymers or polymer electrolytes described herein can be in the crosslinked or uncrosslinked state. Any of the polyamide-based, polyurea-based, and polyphosphazene-based polymers or polymer electrolytes described herein can be crystalline or glassy. Any of the polyamide-based, polyurea-based, and polyphosphazene-based polymers or polymer electrolytes described herein can be copolymerized with other polymers to form copolymers, block copolymers, or graft copolymers. Copolymerization can also affect the mechanical properties of some liquid polymers, making them solid polymer electrolytes. Any of these solid polymer electrolytes described herein can be used as an anode electrolyte and/or a separator electrolyte in a battery cell.

Detailed Description