WO2014129972A1 - Sp3 boron-based single-ion conducting polymer electrolytes - Google Patents

Abstract

This invention relates synthesis and characterizations of a novel family of materials based on sp³ boron-based single-ion conducting polymers and their potential applications in Li-ion batteries. The novel materials can be obtained from reactions between a metal orthoborate and silylated derivatives of organic acids or directly from the reaction between a metal orthoborate and phenols.

Description

SP3 BORON-BASED SINGLE-ION CONDUCTING POLYMER ELECTROLYTES RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Application No. 61/768,650, filed on February 25, 2013. The entire teachings of the above application are incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] Lithium ion secondary batteries have been extensively utilized as a power source in a wide variety of applications because of their high gravimetric and volumetric energy densities, long cycle life, and improved reliability. However, the applicability of lithium ion batteries to broader markets, especially in electric vehicles, has been hindered largely due to the concerns of safety and high costs of the devices.

[0003] For example, the most commonly used liquid electrolyte, lithium

hexafluorophosphate (LiPF₆), has displayed thermal instability and water sensitivity leading to decomposition of the electrolyte and electrodes and shortening of the lifespan of the battery. Combustion of the organic solvent in other liquid electrolytes due to overheating has been responsible for the safety issues observed in many battery devices.

[0004] Solid polymer electrolytes offer many advantages over liquid electrolytes. For example, they can be made at lower cost, they are more flexible in sizes and shapes and they have better safety profiles. Some of the solid polymer electrolytes that have been recently developed include PEO-based, PAN-based, PVDF-based, and PMMA- based complexes. Unfortunately, to date, the reported ionic conductivity of solid polymer electrolytes is still substantially lower than 10^"3 S/cm, which severely limits their broad applications.

[0005] More recently, a compromise between liquid electrolytes and solid polymer electrolytes, gel polymer electrolytes, has been proposed. Gel polymer electrolytes are capable of combining the fast diffusivity of liquids and the strong cohesion of solids, which makes them more conductive than solid electrolytes and more stable than liquid electrolytes. However, the conductivity of gel polymer electrolytes is still too low for relatively high power applications and the leakage of solvent during the electrochemical processes remains to be a serious technical issue.

[0006] Therefore, a need remains for safer, more efficient electrolytes with greater ionic conductivity, longer life cycles, and reliability.

SUMMARY OF THE INVENTION

[0007] The invention pertains to a new class of sp3 boron-based single-ion conducting polymer materials that can serve as both electrolytes and separators for Li- ion batteries. Unlike commercial electrolytes that allow both cations and anions to move toward the negative and positive electrodes, the sp boron-based single-ion conducting polymer electrolytes immobilize anions within the polymeric electrolyte structure and transport lithium ions exclusively. As a consequence, the transfer number of lithium ions is enhanced and polarization effects on the electrodes are minimized.

[0008] The polymer electrolytes and polymer electrolyte composite materials of the present invention with the appropriate film uniformity and thickness can also be utilized directly as battery separators. The use of single-ion conducting polymer electrolytes is also expected to provide improved battery safety compared to small lithium salts in organic solvents.

[0009] The sp3 boron-based single-ion conducting polymer electrolytes of the present invention can be generally classified into three categories of compounds: a boron/aromatic carboxylic acid based polymer framework, a boron/aliphatic acid based polymer framework, and a boron/aromatic phenol based polymer framework. The polymer electrolytes of the invention are thermally and electrochemically stable. More remarkably, the lithium ionic conductivity of these materials is well above 10^"3 S/cm at ambient temperature, similar to the value found for liquid electrolytes, such as LiPF₆ and LiBOB in conventional organic solvents, used in Li-ion batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0010J The foregoing will be apparent from the following more particular description of example embodiments of the invention, as illustrated in the

accompanying drawings.

[0011] FIG. 1 shows a thermogravimetry curve of the sp3 boron-based single-ion conducting polymer electrolyte of Example 1.

[0012] FIG. 2 is a field emission scanning electron micrograph (FE-SEM) of the sp3 boron-based single-ion conducting polymer electrolyte of Example 1.

[0013] FIG. 3 shows the electrochemical stability of a composite electrolyte comprising the sp3 boron-based single-ion conducting polymer of Example 1 , polyvinylidene difluorine, polycarbonate, and ethylene carbonate measured using linear sweep voltammetry (LSV).

[0014] FIG. 4 shows the impedance spectrum of a composite electrolyte comprising the sp3 boron-based single-ion conducting polymer of Example 1 , polyvinylidene difluorine, polycarbonate, and ethylene carbonate at room temperature.

[0015] FIG. 5 shows a thermogravimetry curve of the sp3 boron-based single-ion conducting polymer electrolyte of Example 2.

[0016] FIG. 6 is a field emission scanning electron micrograph (FE-SEM) of the sp3 boron-based single-ion conducting polymer electrolyte of Example 2.

[0017] FIG. 7 shows the electrochemical stability of a composite electrolyte comprising the sp3 boron-based single-ion conducting polymer of Example 2, polyvinylidene difluorine, polycarbonate, and ethylene carbonate measured using linear sweep voltammetry (LSV).

[0018] FIG. 8 shows the impedance spectrum of a composite electrolyte comprising the sp3 boron-based single-ion conducting polymer of Example 2, polyvinylidene difluorine, polycarbonate, and ethylene carbonate at room temperature.

[0019] FIG. 9 shows a thermogravimetry curve of the sp3 boron-based single-ion conducting polymer electrolyte of Example 3.

[0020] FIG. 10 is a field emission scanning electron micrograph (FE-SEM) of the sp3 boron-based single-ion conducting polymer electrolyte of Example 3. [0021] FIG. 11 shows the electrochemical stability of a composite electrolyte comprising the sp3 boron-based single-ion conducting polymer of Example 3, polyvinylidene difluorine, polycarbonate, and ethylene carbonate measured using linear sweep voltammetry (LSV).

[0022] FIG. 12 shows the impedance spectrum of a composite electrolyte comprising the sp3 boron-based single-ion conducting polymer of Example 3, polyvinylidene difluorine, polycarbonate, and ethylene carbonate at room temperature.

[0023] FIG. 13 shows a thermogravimetry curve of the sp3 boron-based single-ion conducting polymer electrolyte of Example 4.

[0024] FIG. 14 is a field emission scanning electron micrograph (FE-SEM) of the sp3 boron-based single-ion conducting polymer electrolyte of Example 4.

[0025] FIG. 15 shows the electrochemical stability of a composite electrolyte comprising the sp3 boron-based single-ion conducting polymer of Example 4, polyvinylidene difluorine, polycarbonate, and ethylene carbonate measured using linear sweep voltammetry (LSV).

[0026] FIG. 16 shows the impedance spectrum of a composite electrolyte comprising the sp3 boron-based single-ion conducting polymer of Example 4, polyvinylidene difluorine, polycarbonate, and ethylene carbonate at room temperature.

[0027] FIG. 17 shows a thermogravimetry curve of the sp3 boron-based single-ion conducting polymer electrolyte of Example 5.

[0028] FIG. 18 is a field emission scanning electron micrograph (FE-SEM) of the sp3 boron-based single-ion conducting polymer electrolyte of Example 5.

[0029] FIG. 19 shows the electrochemical stability of a composite electrolyte comprising the sp3 boron-based single-ion conducting polymer of Example 5, polyvinylidene difluorine, polycarbonate, and ethylene carbonate measured using linear sweep voltammetry (LSV).

[0030] FIG. 20 shows the impedance spectrum of a composite electrolyte comprising the sp3 boron-based single-ion conducting polymer of Example 5, polyvinylidene difluorine, polycarbonate, and ethylene carbonate at room temperature.

[0031] FIG. 21 shows a thermogravimetry curve of the sp3 boron-based single-ion conducting polymer electrolyte of Example 6. [0032] FIG. 22 is a field emission scanning electron micrograph (FE-SEM) of the sp3 boron-based single-ion conducting polymer electrolyte of Example 6.

[0033] FIG. 23 shows the electrochemical stability of a composite electrolyte comprising the sp3 boron-based single-ion conducting polymer of Example 6, polyvinylidene difluorine, polycarbonate, and ethylene carbonate measured using linear sweep voltammetry (LSV).

[0034] FIG. 24 shows the impedance spectrum of a composite electrolyte comprising the sp3 boron-based single-ion conducting polymer of Example 6, polyvinylidene difluorine, polycarbonate, and ethylene carbonate at room temperature.

DETAILED DESCRIPTION OF THE INVENTION DEFINITIONS

[0035] All definitions of substituents set forth below are further applicable to the use of the term in conjunction with another substituent. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0036] "Alkyl" as used alone or as part of a larger moiety as in "alkyl amino" or "haloalkyl" means a saturated aliphatic branched or straight-chain monovalent hydrocarbon radical, typically C1-C8, preferably C1-C4. For example, "(C1-C4) alkyl" means a radical having from 1- 4 carbon atoms in a linear or branched arrangement. "(C1-C4) alkyl" includes methyl, ethyl, propyl, sec-butyl, tert-butyl, and butyl.

[0037] Alkoxy" refers to the group -O-R where R is "alkyl", "cycloalkyl",

"alkenyl", or "alkynyl". The term "alkoxyalkyl" means alkyl substituted with an alkoxy group. Examples of alkoxy groups include methoxy, ethoxy, propoxy, butoxy and the like. "(C1-C4) alkoxy" refers to the group -O-R where R is a radical having from 1-4 carbons in a linear or branched arrangement.

[0038] As used herein, the term an "aromatic ring" or "aryl" refers to an aromatic carbocyclic group of from 6 to 18 carbon atoms having a single ring or multiple condensed rings. For example, "(C6-C10) aryl" means an aromatic ring having between 6-10 carbons. The term "aryl" also includes aromatic carbocycle(s) fused to cycloalkyl or heterocycloalkyl groups. Examples of suitable aryl groups include, but are not limited to, phenyl, tolyl, anthacenyl, fiuorenyl, indenyl, azulenyl, and naphthyl, benzo[< ][l,3]dioxole, phenanthrenyl, as well as benzo-fused carbocyclic moieties such as 5,6,7,8-tetrahydronaphthyl and the like. An aryl group can be unsubstituted or substituted with one or more substituents, e.g., substituents as described herein for alkyl groups (including without limitation alkyl and alkyl substituted with one or more halo), hydroxy, alkoxy, alkylthio, cyano, halo, amino, boronic acid (-B(OH)₂) and nitro. In certain embodiments, the aryl group is a monocyclic ring comprising 6 carbon atoms.

[0039] "Halogen" and "halo" are interchangeably used herein and each refers to fluorine, chlorine, bromine, or iodine.

[0040] The terms "haloalkyl", "halocycloalkyl" and "haloalkoxy" mean alkyl, cycloalkyl, or alkoxy, as the case may be, substituted with one or more halogen atoms.

[0041] "Acyl" or "Ac" refers to R"-C(0)-, where R" is H, alkyl, substituted alkyl, heteroalkyl, substituted heteroalkyl, alkenyl, substituted alkenyl, aryl, alkylaryl, or substituted alkylaryl. "(C1-C4) acyl" refers to R"-C(0)-, where R" is a radical having from 1 -4 carbons in a linear or branched arrangement.

[0042] "Amino" means -NH₂; "alkylamine" and "dialkylamine" mean -NHR and - NR₂, respectively, where R is an alkyl group. "Cycloalkylamine" and

"dicycloalkylamine" mean -NHR and -NR₂, respectively, where R is a cycloalkyl group. "(C1-C4) alkyl amine" refers to an amine group, -NHR, where R is a radical having from 1-4 carbons in a linear or branched arrangement. Similarly, "(C1-C4) dialkyl amine" refers to an amine group, -NR₂, where each R is a radical having from 1-4 carbons in a linear or branched arrangement.

[0043] The term "alkali metal", as used herein, is defined as a metal found within the Group (I) element of the periodic table. The alkali metals of the invention include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs) and francium (Fr).

SP3 BORON-BASED SINGLE-ION CONDUCTING POLYMER ELECTROLYTES

[0044] A description of example embodiments of the invention follows

[0045] The present invention relates to a new class of sp³ boron-based one- dimensional and three-dimensional framework single-ion polymer electrolytes. The single-ion conducting polymers of the invention can serve as both electrolytes and separators for Li-ion batteries.

[0046] In a first aspect, the present invention relates to sp3 boron-based single-ion conducting polymer electrolyte, comprising a reaction product obtained by reacting: an alkali metal alkoxy orthoborate salt and an anion stabilizing monomer, the anion stabilizing monomer comprising an aromatic carboxylic acid, an aliphatic carboxylic acid, or an aromatic phenol. The average molecular weight Mw of the sp3 boron-based single-ion conducting polymer electrolyte can be between about 5,000 to about 100,000. The term "anion stabilizing monomer" refers to a monomer that can delocalize and attenuate the nucleophilicity of the anion electron pair.

[0047] "Alkali metal alkoxy orthoborate salt", as used herein, refers to an alkali metal salt of the ester of an orthoboric acid. Alkali metals of the alkali metal alkoxy orthoborate salt can include, for example, Li, Na, K, Cs, Rb and Fr. In one

embodiment, the alkali metal of the alkali metal alkoxy orthoborate salt is lithium. In another embodiment, the alkali metal of the alkali metal alkoxy orthoborate salt is sodium. In yet another embodiment, the alkali metal of the alkali metal alkoxy orthoborate salt is potassium.

[0048] "Aromatic carboxylic acid" refers to a compound containing one or more carboxylic acid groups bonded directly to an aromatic ring. In one embodiment, the aromatic carboxylic acid has the following structural formula:

[0049] wherein:

[0050] Ri is each independently H, halogen, an optionally substituted (C1-C4) alkyl, an optionally substituted (C1-C4) alkoxy, an optionally substituted (C1-C4) alkyl amino, an optionally substituted (C1-C4) dialkyl amino, an optionally substituted (Cl- C4)acyl, or an optionally substituted (C 1 -C4)NR₃C(0), wherein the optional substituents are each independently H, halogen, (C1-C4) alkyl, (C1-C4) alkoxy, (CI- C4) halo alkyl, (C1-C4) haloalkoxy, (C1-C4) alkyl amino, (C1-C4) dialkyl amino, or (Cl-C4)acyl;

[0051] R₃ is each independently H or an optionally substituted (C1-C4) alkyl, wherein the optional substituents on (C1-C4) alkyl are each independently H, halogen, or (C1-C4) alkoxy; and ml is an integer from 1 to 2.

[0052] In one embodiment, Ri is H. In another embodiment, Ri is F and ml is 1.

[0053] In another embodiment, the aromatic carboxylic acid has the following structural formula:

[0054] wherein:

[0055] R₂ is each independently H, halogen, an optionally substituted (C1-C4) alkyl, an optionally substituted (C1-C4) alkoxy, an optionally substituted (C1-C4) alkyl amino, an optionally substituted (C1-C4) dialkyl amino, an optionally substituted (Cl- C4)acyl, or an optionally substituted (C1-C4)NR₃C(0), wherein the optional substituents are each independently H, halogen, (C1-C4) alkyl, (C1-C4) alkoxy, (Cl- C4) halo alkyl, (C1-C4) haloalkoxy, (C1-C4) alkyl amino, (C1-C4) dialkyl amino, or (Cl-C4)acyl;

[0056] R₃ is each independently H or an optionally substituted (C1-C4) alkyl, wherein the optional substituents on (C1-C4) alkyl are each independently H, halogen, or (C1-C4) alkoxy; and ni2 is an integer from 1-4.

[0057] In one embodiment, R₂ is H. In another embodiment, R₂ is F and m2 is 1.

[0058] "Aromatic phenol" refers to a compound containing a hydroxyl, -OH, bonded directly to an aromatic ring. In one embodiment, the aromatic phenol has the following structural formula:

[0059] wherein:

[0060] R4 is each independently H, halogen, an optionally substituted (CI -C4) alkyl, an optionally substituted (C1-C4) alkoxy, an optionally substituted (CI -C4) alkyl amino, an optionally substituted (C1-C4) dialkyl amino, an optionally substituted (Cl- C4)acyl, or an optionally substituted (C1-C4)NR₈C(0), wherein the optional substituents are each independently H, halogen, (C1-C4) alkyl, (C1-C4) alkoxy, (Cl- C4) halo alkyl, (C1-C4) haloalkoxy, (C1-C4) alkyl amino, (C1-C4) dialkyl amino, or (Cl-C4)acyl;

[0061] Rg is each independently H or an optionally substituted (C1-C4) alkyl, wherein the optional substituents on (C1-C4) alkyl are each independently H, halogen, or (C1-C4) alkoxy; and m₄ is an integer from 1 to 4.

[0062] In one embodiment, R₄ is H. In another embodiment, R4 is F and m4 is 1.

[0063] In another embodiment, the aromatic phenol has the following structural formula:

[0064] wherein:

[0065] R₅ is each independently H, halogen, an optionally substituted (C1-C4) alkyl, an optionally substituted (C1-C4) alkoxy, an optionally substituted (C1-C4) alkyl amino, an optionally substituted (C1-C4) dialkyl amino, an optionally substituted (Cl- C4)acyl, or an optionally substituted (C1-C4)NR₃C(0), wherein the optional substituents are each independently H, halogen, (C1-C4) alkyl, (C1-C4) alkoxy, (Cl- C4) halo alkyl, (C1-C4) haloalkoxy, (C1-C4) alkyl amino, (C1-C4) dialkyl amino, or (Cl-C4)acyl;

[0066] R₆ is each independently H, halogen, an optionally substituted (C1-C4) alkyl, an optionally substituted (C1-C4) alkoxy, an optionally substituted (C1-C4) alkyl amino, an optionally substituted (C1-C4) dialkyl amino, an optionally substituted (Cl- C4)acyl, or an optionally substituted (C1-C4)NR₈C(0), wherein the optional substituents are each independently H, halogen, (C1-C4) alkyl, (C1-C4) alkoxy, (Cl- C4) halo alkyl, (C1-C4) haloalkoxy, (C1-C4) alkyl amino, (C1-C4) dialkyl amino, or (Cl-C4)acyl;

[0067] R-3 and Rg are each independently H or an optionally substituted (C1-C4) alkyl, wherein the optional substituents on (C1-C4) alkyl are each independently H, halogen, or (C1-C4) alkoxy; and

[0068] each m₅ and m₆ is independently an integer from 1 to 4.

[0069] The aromatic phenol can have R5 and R₆ groups that are the same or different. For example, R₅ may be hydrogen and Re may be alkyl or R₅ and R₆ may both be hydrogen. In one embodiment, R₅ and R₆ are hydrogen. In another

embodiment, R5 is hydrogen and R<5 is fluorine. In yet another embodiment, R₅ is fluorine and R^, is hydrogen. In another embodiment, R₅ and R₆ are fluorine.

[0070] In another embodiment, the aromatic phenol has the following structural formula:

[0071] wherein:

[0072] R₇ is each independently H, halogen, an optionally substituted (C1-C4) alkyl, an optionally substituted (C1-C4) alkoxy, an optionally substituted (C1-C4) alkyl amino, an optionally substituted (C1-C4) dialkyl amino, an optionally substituted (Cl- C4)acyl, or an optionally substituted (C1-C4)NR₈C(0), wherein the optional substituents are each independently H, halogen, (C1-C4) alkyl, (C1-C4) alkoxy, (Cl- C4) halo alkyl, (C1-C4) haloalkoxy, (C1-C4) alkyl amino, (C1-C4) dialkyl amino, or (Cl-C4)acyl;

[0073] Rg is each independently H or an optionally substituted (C1-C4) alkyl, wherein the optional substituents on (C1-C4) alkyl are each independently H, halogen, or (C1-C4) alkoxy; and m₇ is an integer from 1 to 3. In one embodiment R₇ is 2014/000069

- 1 1 - hydrogen. In another embodiment, R is fluorine and m7 is 1. In yet another

embodiment, R₇ is fluorine and m7 is 2.

[0074] "Aliphatic carboxylic acid" refers to a compound containing one or more carboxylic acid groups bonded directly to an alkane, an alkene, an alkyne or a

carbocyclic non-aromatic ring. In one embodiment, the aromatic phenol has the following structural formula:

[0075] wherein:

[0076] each R₉ and Rio are independently H, halogen, an optionally substituted (C1-C4) alkyl, an optionally substituted (C1-C4) alkoxy, an optionally substituted (Cl- C4) alkyl amino, an optionally substituted (C1-C4) dialkyl amino, an optionally substituted (Cl-C4)acyl, or an optionally substituted (Cl-C4)NRuC(0), wherein the optional substituents are each independently H, halogen, (C1-C4) alkyl, (C1-C4) alkoxy, (C1-C4) halo alkyl, (C1-C4) haloalkoxy, (C1-C4) alkyl amino, (C1-C4) dialkyl amino, or (Cl-C4)acyl; and

[0077] Ri _\ is each independently H or an optionally substituted (C 1 -C4) alkyl, wherein the optional substituents on (C1-C4) alkyl are each independently H, halogen, or (C1-C4) alkoxy.

[0078] The aliphatic carboxylic acid can have R₉ and Rio groups that are the same or different. For example, R₉ may be hydrogen and R[₀ may be alkyl or R₉ and Rio may both be hydrogen. In one embodiment, R₉ and R[₀ are hydrogen. In another embodiment, R₉ and R₁₀ are trifluoromethyl. In another embodiment, R₉ is hydrogen and Rio is trifluoromethyl. In another embodiment, R₉ and Rio are methyl. In another embodiment, R₉ is hydrogen and Rio is methyl.

[0079] In another embodiment, the sp3 boron-based single-ion conducting polymer electrolyte is represented by Structural Formula (I):

[0080] wherein:

[0081] M is H or an alkali metal;

[0082] can be a single or double bond;

[0083] each R_\ and R₂ are independently H, halogen, an optionally substituted (Cl- C4) alkyl, an optionally substituted (C1-C4) alkoxy, an optionally substituted (C1-C4) alkyl amino, an optionally substituted (C1-C4) dialkyl amino, an optionally substituted (Cl-C4)acyl, or an optionally substituted (C1-C4)NR₃C(0), wherein the optional substituents are each independently H, halogen, (C1-C4) alkyl, (C1-C4) alkoxy, (Cl- C4) halo alkyl, (C1-C4) haloalkoxy, (C1-C4) alkyl amino, (C1-C4) dialkyl amino, or (Cl-C4)acyl; or

[0084] Ri and R₂ together form a (C6-C10) aryl ring optionally substituted with 1

[0085] R₃ and R₅ are each independently H or an optionally substituted (C1-C4) alkyl, wherein the optional substituents on (C1-C4) alkyl are each independently H, halogen, or (C1-C4) alkoxy;

[0086] R4 is each independently H, halogen, an optionally substituted (C1-C4) alkyl, an optionally substituted (C1-C4) alkoxy, an optionally substituted (C1-C4) alkyl amino, an optionally substituted (C1-C4) dialkyl amino, an optionally substituted (Cl- C4)acyl, or an optionally substituted (C1-C4)NR₅C(0), wherein the optional substituents are each independently H, halogen, (C1-C4) alkyl, (C1-C4) alkoxy, (Cl- C4) halo alkyl, (C1-C4) haloalkoxy, (C1-C4) alkyl amino, (C1-C4) dialkyl amino, or (Cl-C4)acyl;

[0087] and n is an integer from 1 - 100. [0088] The Ri and R₂ groups on Structural Formula (I) can be the same or different. For example, Ri may be hydrogen and R₂ may be alkyl or Ri and R₂ may both be hydrogen. In one embodiment, Ri and R₂ are hydrogen. In another embodiment, Ri and R₂ are trifluoromethyl. In another embodiment, Ri is hydrogen and R₂ is trifluoromethyl. In another embodiment, Ri and R₂ are methyl. In another

embodiment, Ri is hydrogen and R₂ is methyl.

[0089] The Ri and R₂ groups on Structural Formula (I) together can also form an aryl ring. The aryl ring can include, but is not limited to, optionally substituted 6- membered aryl rings and optionally substituted 10-membered bicyclic aryl rings. The aryl ring can be substituted with 1 to 4 R4 groups which can be the same or different. For example, the aryl ring can have four R4 groups that are all hydrogen or the aryl ring can have an R4 group that is fluorine and three R₄ groups that are hydrogen. In one embodiment, the aryl ring is substituted with four R₄ groups that are hydrogen. In another embodiment, the aryl ring is substituted with three R₄ groups that are hydrogen and one R4 group that is fluorine. In another embodiment, the aryl ring is substituted with two R4 groups that are hydrogen and two R₄ groups that are fluorine.

[0090] In another embodiment, the sp3 boron-based single-ion conducting polymer electrolyte of Claim 1 represented by Structural Formula (II):

[0091] wherein:

[0092] M is H or an alkali metal;

[0093] each X is independently O or C(O);

[0094] each R_\ is independently H, halogen, an optionally substituted (C 1 -C4) alkyl, an optionally substituted (C1-C4) alkoxy, an optionally substituted (C1-C4) alkyl amino, an optionally substituted (C1-C4) dialkyl amino, an optionally substituted (CI- C4)acyl, or an optionally substituted (C1-C4)NR₃C(0), wherein the optional substituents are each independently H, halogen, (C1-C4) alkyl, (C1-C4) alkoxy, (Cl- C4) halo alkyl, (C1-C4) haloalkoxy, (C1-C4) alkyl amino, (C1-C4) dialkyl amino, or (Cl-C4)acyl;

[0095] each R₂ is independently H, halogen, an optionally substituted (C1-C4) alkyl, an optionally substituted (C1-C4) alkoxy, an optionally substituted (C1-C4) alkyl amino, an optionally substituted (C1-C4) dialkyl amino, an optionally substituted (Cl- C4)acyl, or an optionally substituted (C1-C4)NR₄C(0), wherein the optional substituents are each independently H, halogen, (C1-C4) alkyl, (C1-C4) alkoxy, (Cl- C4) halo alkyl, (C1-C4) haloalkoxy, (C1-C4) alkyl amino, (C1-C4) dialkyl amino, or (Cl-C4)acyl;

[0096] R₃, R4, and R are each independently H or an optionally substituted (CI - C4) alkyl, wherein the optional substituents on (C1-C4) alkyl are each independently H, halogen, or (C1-C4) alkoxy;

[0097] L is a bond or a (C6-C 10) aryl ring substituted with 1 to 4 R₅;

[0098] each R₅ is independently H, halogen, an optionally substituted (C1-C4) alkyl, an optionally substituted (C1-C4) alkoxy, an optionally substituted (C1-C4) alkyl amino, an optionally substituted (C1-C4) dialkyl amino, an optionally substituted (Cl- C4)acyl, or an optionally substituted (C1-C4)NR₆C(0), wherein the optional substituents are each independently H, halogen, (C1-C4) alkyl, (C1-C4) alkoxy, (Cl- C4) halo alkyl, (C1-C4) haloalkoxy, (C1-C4) alkyl amino, (C1-C4) dialkyl amino, or (Cl-C4)acyl;

[0099] each mi and m₂ is independently an integer from 1 to 4 ; and n is an integer from 1-100.

[00100] The sp3 boron-based single-ion conducting polymer electrolyte having the structure shown in Structural Formula (II) can have Ri and R₂ groups that are the same or different. For example, Ri may be hydrogen and R₂ may be alkyl or R[ and R₂ may both be hydrogen. In one embodiment, Ri and R₂ are hydrogen. In another

embodiment, Ri is hydrogen and R₂ is fluorine. In yet another embodiment, i is fluorine and R₂ is hydrogen. In another embodiment, Ri and R₂ are fluorine. [00101] The sp3 boron-based single-ion conducting polymer electrolyte having the structure shown in Structural Formula (II) can have an L group that is bond or an L group that is an aryl ring. In one embodiment, L is a bond and Ri and R₂ are H. In another embodiment, L is an optionally substituted aryl ring.

[00102] When L is an aryl ring, the aryl ring can include, but is not limited to, optionally substituted 6-membered aryl rings and optionally substituted 10-membered bicyclic aryl rings. The aryl ring can be substituted with 1 to 4 R₅ groups which can be the same or different. For example, the aryl ring can have four R₅ groups that are all hydrogen or the aryl ring can have an R₅ group that is fluorine and three R₅ groups that are hydrogen. In one embodiment, the aryl ring is substituted with four R₅ groups that are hydrogen. In another embodiment, the aryl ring is substituted with three R₅ groups that are hydrogen and one R₅ group that is fluorine. In another embodiment, the aryl ring is substituted with two R₅ groups that are hydrogen and two R₅ groups that are fluorine.

[00103] In another embodiment, the sp3 boron-based single-ion conducting polymer electrolyte of Claim 1 represented by Structural Formula (III):

[00104] wherein:

[00105] M is H or an alkali metal;

[00106] each Ri is independently H, halogen, an optionally substituted (C1-C4) alkyl, an optionally substituted (C1-C4) alkoxy, an optionally substituted (C 1 -C4) alkyl amino, an optionally substituted (C1-C4) dialkyl amino, an optionally substituted (Cl- C4)acyl, or an optionally substituted (C1-C4)NR₃C(0), wherein the optional substituents are each independently H, halogen, (C1-C4) alkyl, (C1-C4) alkoxy, (Cl - C4) halo alkyl, (C1-C4) haloalkoxy, (C1-C4) alkyl amino, (C1-C4) dialkyl amino, or (Cl-C4)acyl;

[00107] each R₂ is independently H, halogen, an optionally substituted (C1-C4) alkyl, an optionally substituted (C1-C4) alkoxy, an optionally substituted (C1-C4) alkyl amino, an optionally substituted (C1-C4) dialkyl amino, an optionally substituted (Cl- C4)acyl, or an optionally substituted (C1-C4)NR₄C(0), wherein the optional substituents are each independently H, halogen, (C1-C4) alkyl, (C1-C4) alkoxy, (Cl- C4) halo alkyl, (C1-C4) haloalkoxy, (CI -C4) alkyl amino, (C1 -C4) dialkyl amino, or (Cl-C4)acyl;

[00108] R₃ and R4 are each independently H or an optionally substituted (C1-C4) alkyl, wherein the optional substituents on (C1 -C4) alkyl are each independently H, halogen, or (C1-C4) alkoxy;

[00109] each mi and m₂ is independently an integer from 1 to 4 ; and n is an integer from 1-100.

[00110] The sp3 boron-based single-ion conducting polymer electrolyte having the structure shown in Structural Formula (III) can have R| and R₂ groups that are the same or different. For example, Ri may be hydrogen and R₂ may be alkyl or Ri and R₂ may both be hydrogen. In one embodiment, Ri and R₂ are hydrogen. In another

embodiment, Ri is hydrogen, R₂ is fluorine and ml is 1. In yet another embodiment,

is fluorine, ml is 1 and R₂ is hydrogen. In another embodiment, Ri and R₂ are fluorine and m 1 and ml are 1.

[00111] In yet another embodiment, the sp3 boron-based single-ion conducting polymer ele

[00112] wherein:

[00113] n is selected to provide a polymer with a weight average molecular weight in the range of about 8,000 to about 40,000.

[00114] M in Structural Formulae (I)-(IH) can be H or an alkali metal. Alkali metals can include, for example, Li, Na, K, Cs, Rb and Fr. In one embodiment, M is lithium. In another embodiment, M is hydrogen. In yet another embodiment, M is sodium. In another embodiment, M is potassium.

[00115] As used herein, a conductive polymer is a polymer that possesses conducting properties as opposed to possessing insulating electron-transport properties. As used herein, the term "polymer" refers to a macromolecule made of repeating monomer units. The term "copolymer" is defined as a polymer of at least two chemically distinct monomers. The copolymers of the invention include, but are not limited to, alternating copolymers, statistical copolymers, block copolymers, random copolymer, and graft copolymers. The polymers and copolymers of the invention also include, but are not, limited to, dendrimers and hyperbranched polymers and copolymers. In one embodiment, the boron-based single-ion conducting polymer electrolyte is a polymer comprising at least one monomer. In another embodiment, the boron-based single-ion conducting polymer electrolyte is a copolymer comprising one or more monomers.

[00116] "Ion transference number" is defined to describe the current contribution of various ions in the electrolyte. Typically, the lithium transference number in lithium ion batteries is around 0.3. Increasing this value to unit is a good way to solve the problem of cell polarization, especially at a high charge/discharge rate. The boron- based single-ion polymer electrolyte of the invention can have an ion transference number between about 0.2 to about 0.95. Preferably the polymer electrolyte has an ion transference number between about 0.5 to about 0.95; more preferably between about 0.7 to about 0.95; even more preferably between about 0.85 to about 0.95.

[00117] The boron-based single-ion polymer electrolyte of the invention

demonstrates high ionic conductivity. The polymer electrolyte of the invention can have an ionic conductivity between about 10^" S/cm to about 10^" S/cm. Preferably the polymer electrolyte has an ionic conductivity between about 10^" 3 S/cm to about 10^" 8 S/cm; more preferably between about lO ³ S/cm to about 10^"6 S/cm; even more preferably between about 10^'3 S/cm to about 10^"4 S/cm.

[00118] The boron-based polymer electrolyte of the present invention can have a molecular weight between about 5,000 to about 400,000. Preferably, the boron-based polymer electrolyte has a molecular weight between about 8,000 to about 200,000; more preferably between about 8,000 to about 100,000; even more preferably between about 8,000 to about 40,000.

[00119] In another aspect, the present invention also relates to a method for synthesizing a sp3 boron-based single-ion conducting polymer electrolyte, comprising: a) heating a mixture of a carboxylic acid and a silylating agent to form a silylated carboxylic acid intermediate; and b) heating a mixture of the silylated carboxylic acid intermediate with a metal alkoxy orthoborate salt to form a sp3 boron-based single-ion conducting polymer electrolyte.

[00120] Various silylating agent agents can be used to silylate the carboxylic acid. For example, silylating agents include, but are not limited to, hexamethyldisiloxane (HMDS), chlorotrimethylsilane, methyldichlorosilane, methyldimethoxysilane, methyldiethoxysilane, triethoxysilane, and trimethoxysilane. A polar or non-polar solvent can be used in the silylation of the carboxylic acid. In one embodiment, the solvent used in silylation of the carboxylic acid is dichloroethane (DCE).

[00121] In yet another aspect, the present invention also relates to method for synthesizing a sp3 boron-based single-ion conducting polymer electrolyte, comprising: heating a mixture of an alcohol and an alkoxy orthoborate salt to form an sp3 boron- based single-ion conducting polymer electrolyte.

[00122] There are various alkoxy orthoborate salts that can be used to form the boron-based single-ion polymer electrolyte. Examples of alkoxy orthoborate salts include, but are not limited to, lithium tetramethanolatoborate, sodium tetraborate, and potassium borate. A polar or non-polar solvent can be used with metal alkoxy orthoborate to make the boron-based single-ion polymer electrolytes. In one embodiment, the solvent is a polar solvent. In another embodiment, the solvent is a non-polar solvent. In yet another embodiment, the solvent used is N,N

dimethylforamide (DMF). In another embodiment, the solvent is acetonitrile (ACN).

[00123] The polymer electrolytes of the present invention can also be made by reacting a silylated intermediate with a metal borohydride. The metal borohydride that can be used to make the boron-based single-ion polymer electrolytes of the invention include, but are not limited to, lithium borohydride, sodium borohydride, and potassium borohydride. A polar or non-polar solvent can be used with metal borohydride to make the boron-based single-ion polymer electrolytes. In one embodiment, the solvent is a polar solvent. In another embodiment, the solvent is a non-polar solvent. In yet another embodiment, the solvent used is tetrahydrofuran (THF). The reaction can also be run without solvent. [00124] In another aspect, the present invention relates to a method for manufacturing a boron-based single-ion conducting composite film, comprising: a) dissolving a single-ion polymer electrolyte and second polymer in a solvent to form a solution mixture; and b) evaporating the solvent at a temperature between about 50 °C to about 150 ⁰ C to form the single-ion conducting composite film. The second polymer that can be used to make the composite film can be an electrochemically stable polymer or a copolymer of low or high molecular weight. The second polymer can have a low or a high transition glass transition temperature. The monomers that can be used to synthesize the second polymers or copolymers of the present invention include, but are not limited to, vinylidene fluoride, trifluoroethylene, chlorotrifluoroethylene, tetrafluoroethylene, hexafluoropropylene, 1,1-chlorofluoroethylene, 11- aminoundecanoic acid, polyethylene oxide, acrylonitrile, methylmethacrylate, and thiourea, or a combination thereof. The second polymer used to make the composite film can be a copolymer comprising two or more monomers. In one embodiment, the second polymer is polyvinylidene fluoride (PVDF). In another embodiment, the second polymer is polyethylene oxide (PEO). In yet another embodiment, the second polymer is polymethylmethacrylate (PMMA). In another embodiment, the second polymer has a low glass transition temperature (Tg). In another embodiment, the second polymer is a high molecular weight polymer.

[00125] The solvent used in the methods of the present invention can be polar or non-polar. As used herein, "non-polar solvents" refers to solvents with a dielectric constant of less than 15 and can include, but are not limited to, aliphatic solvents, aromatic solvents, and other aprotic solvents. Examples of non-polar solvents include, but are not limited to, pentane, hexanes, heptane, hexadecane, cyclohexane, benzene, toluene, xylene, tetrahydrofuran, diethylether, ethyl acetate and methylene chloride.

[00126] "Polar solvents," as used herein, refer to solvents with a dielectric constant of more than 15 and include, but are not limited to, aprotic and protic solvents.

Examples of polar solvents include, but are not limited to, acetone, N,N- dimethylformamide, N-methyl-2-pyrrolidinone, acetonitrile, propylene carbonate, ethylene carbonate, acetic acid, formic acid, methanol, ethanol, n-propanol,

isopropanol, n-butanol, nitromethane and water. In one embodiment, the solvent is dimethylformamide. In another embodiment, the solvent is N-methyl-2-pyrrolidinone. In yet another embodiment, the solvent is water. The solvent can also be a mixture of one or more solvents. For example, the solvent can be a mixture of propylene carbonate and ethylene carbonate. The mixture of one or more solvents can be present in varying ratios. For example, the solvent mixture can be a mixture of propylene carbonate and ethylene carbonate with a ratio of propylene carbonate and ethylene carbonate of 1 :1. The ratio of a mixture of solvents can be between about 10:1 to about 1 :1 ; preferably about 1 :1 to 8:1 ; more preferably 1 :1 to about 5:1. In one embodiment, the solvent used for making the composite film is a mixture of propylene carbonate and ethylene carbonate.

[00127] The boron-based single-ion polymer electrolytes are useful in a variety of contexts. The specific industrial applications include energy storage and conversion devices, such as solid-state battery (e.g., lithium ion battery, sodium ion battery), fuel cells and supercapacitors.

[00128] In another aspect, the present invention relates to a battery, comprising: a sp3 boron-based single-ion conducting polymer electrolyte. Solid state batteries made with the boron-based single-ion polymer electrolytes of the present invention can comprise a positive electrode or anode, a negative electrode or cathode, and the boron- based single-ion polymer electrolyte. In one embodiment, the battery comprises a boron-based single-ion polymer electrolyte, a positive electrode and a negative electrode. The anode and the cathode can be made from a variety of materials. The materials that can be used for the cathode include, but are not limited to, LiMn₂0₄, LiFeP₄, LiCo0₂, LiNi0₂, LiNi₀.₈Co₀.₂O₂, LiNi_{1 3}Coi/3Mn₁/₃0₂, Li₂FeSi0₄, LiFeS0 F, LiFeB0₃, and LiMni_.5Ni₀.₅O₄. The materials that can be used for the anode include, but are not limited to, carbon-based materials, silicon, Sn0₂, CoO, Ti0₂, Li₄Ti₅Oi2, V₂0₅, Mn0₂, NiO, Fe₂0₃, and Co₃0₄.

[00129] In a Li-ion battery device, both the electrolyte and the separator play an important role in performance enhancement of the battery cell. An ideal electrolyte should possess the following attributes: good ionic conductivity in a wide temperature range, high electrochemical stability, ability to form SEI layer on the active electrode materials, high volumetric and gravimetric densities and, more importantly, good safety and reliability. An ideal separator should bear two important functions. One is to serve as a membrane that separates anode and cathode to prevent short circuiting and the other is to act as a medium to facilitate the flow of lithium ions between anode and cathode.

[00130] The sp³ boron-based single-ion conducting polymers of the present invention can serve as both electrolytes and separators for Li-ion batteries. The thermal stability of these materials can vary the polymer electrolytes being stable between about 160 °C to about 600 °C. The electrochemical stability can be in the range of about 4.0 V to about 5.2 V. More remarkably, the lithium ionic conductivity of these materials is well above 10^"3 S/cm at ambient temperature, similar to the value found in liquid electrolytes, such as LiPF₆ and LiBOB in conventional organic solvents used in Li-ion batteries.

[00131 J Example 1 is a one-dimensional sp boron-based framework, which displays great rigidity supported by the aromatic components. Example 2 is a three-dimensional sp³ boron framework with strong structural rigidity. Example 3 is a one-dimensional sp³ boron-based framework with a high degree of flexibility arising from the "softness" of aliphatic acid is demonstrated. The aromatic phenol based sp3 boron-based single- ion conducting polymer electrolytes, shown in example 4 to 6, all exhibit three- dimensional structures dictated by the selected precursor structures.

[00132] FIG. 1 shows the thermogravimetry (TG) curve of poly(pyromellitic acid borate) (PPAB) (Example 1). The first degradation with a weight loss of 3% can be attributed to the loss of water present below about 100 °C. The sample does not begin to decompose until the temperature is above about 300 °C, indicating a good thermal stability.

[00133] FIG. 2 is a field emission scanning electron micrograph (FE-SEM) of PPAB. The PPAB particles of the sample have a strip-like shape with a particle dimension of about 20 μπι X 3 μιη X 3 um.

[00134] FIG. 3 shows the electrochemical stability of PPAB. Linear sweep voltammetry (LSV) was carried out of a PBAB composite material to examine the electrochemical stability and the current-voltage response of the composite single ionic conductor polymer electrolyte. As shown in FIG. 3, the poly inylidene difluoride/PPAB/ ethylene carbonate : polycarbonate (PVDF/PPAB/EC:PC) composite electrolyte possesses a current response of about 5.2 V versus Li/Li⁺. The

PVDF/PPAB EC:PC composite electrolyte has a suitable electrochemical properties for use in high-voltage lithium-based ion batteries such as LiCo0₂-based, LiFeP0₄-based, LiNi0₂-based and LiMn₂0₄-based lithium ion batteries.

[00135] FIG. 4 shows the impedance spectrum and Nyquist plots of the

PVDF/PPAB/EC:PC composite electrolyte at room temperature. The diagram of the Nyquist plot includes two elements: a suppressed semicircle in the high frequency regime that corresponds to bulk resistance and a straight line in the lower frequency regime that corresponds to interfacial resistance controlled by the diffusion of the charged particles. This electrochemical behavior is typical for single ion conducting polymer electrolytes with the impedance accounting for both the bulk resistance and the interfacial resistance. Using the equation, σ = L/(R* A), where L and A are the thickness and area of composite membrane, respectively, and R is the resistance of composite membrane, the ionic conductivity of the PVDF/PPAB/EC:PC membrane was calculated to be about 1.26 mS/cm, indicating that the composite membrane is well suited for use in high power lithium ion batteries. Use of this type of membrane in battery devices will allow the elimination of conventional separators. Thus, the boron- based single ion composite membranes can serve as both electrolytes and separators simultaneously.

[00136] FIG. 5 shows the thermogravimetry (TG) curve of Poly (terephthalic acid borate) (PTAB). The sample undergoes two steps of decomposition. In the first step (at about 570 °C), there is a weight loss of about 30% that can be attributed to the degradation of the boron component with two carboxyl groups. In the second step, another 30% weight loss is observed at a temperature range of about 660 °C to about 780 °C that can be attributed to the degradation of benzoic acid group. The remaining lithium benzoate begins to decompose at about 780 °C. PTAB exhibits excellent thermal stability.

[00137] FIG. 6 is a field emission scanning electron micrograph (FE-SEM) and morphology of PTAB. The micrograph shows that the particles of the sample are highly uniform with a length of about 2 μη . [00138J FIG. 7 shows the electrochemical stability of PTAB. Linear sweep voltammetry (LSV) was carried out of a PTAB composite material to examine the electrochemical stability and the current- voltage response of the composite single ionic conductor polymer electrolyte. As shown in FIG. 7, the polyvinylidene

difluoride PTAB/ ethylene carbonate : polycarbonate (PVDF/PTAB/EC:PC) composite electrolyte possesses a current response of about 4.0 V versus Li/Li⁺. It is concluded that the PVDF/PTAB/EC:PC composite electrolyte has suitable electrochemical properties for use in high-voltage lithium-based ion batteries such as LiCo0₂-based, LiFeP0₄-based, LiNi0₂-based and LiMn₂0 -based lithium ion batteries.

[00139] FIG. 8 shows the impedance spectrum and Nyquist plots of the

PVDF/PTAB/EC:PC composite electrolyte at room temperature. The diagram of the Nyquist plot includes two elements: a suppressed semicircle in the high frequency regime that corresponds to bulk resistance and a straight line in the lower frequency regime that corresponds to interfacial resistance controlled by the diffusion of the charged particles. This electrochemical behavior is typical for single ion conducting polymer electrolytes with the impedance accounting for both the bulk resistance and the interfacial resistance. Using the equation above, σ = L/(R*A), the ionic conductivity of the PVDF/PTAB/EC:PC membrane was calculated to be about 0.98 mS/cm at room temperature, indicating that the composite membrane is well suited for use in high power lithium ion batteries.

[00140] FIG. 9 shows the thermogravimetry (TG) curve of poly(l,2,3,4- butanetetracarboxylic acid borate) (PBAB). As shown in FIG. 9, the sample undergoes decomposition at various temperatures. Between about 250 °C and about 570 °C, there is a series of weight loss steps leading to a loss of about 70% that can be attributed to the degradation of the boron component bound to the carboxyl group, the second carboxyl group, and the aliphatic chain respectively. The remaining lithium formate begins to decompose at about 750 °C. PBAB exhibits good thermal stability.

[00141] FIG. 10 is a field emission scanning electron micrograph (FE-SEM) and morphology of PBAB. The micrograph shows that the particles of the sample are well- formed uniform particles with a size of about 100 nm. 2014/000069

- 25 -

[00142] FIG. 11 shows the electrochemical stability of PBAB. Linear sweep voltammetry (LSV) was carried out of a PBAB composite material to examine the electrochemical stability and the current- voltage response of the composite single ionic conductor polymer electrolyte. As shown in FIG. 11, the polyvinylidene

difluoride/PBAB/ ethylene carbonate: polycarbonate (PVDF/PBAB/EC:PC) composite electrolyte possesses a current response of about 4.5 V versus Li/Li⁺. It is concluded that the PVDF/PBAB/EC.PC composite electrolyte has suitable electrochemical properties for use in high- voltage lithium-based ion batteries such as LiCoOi-based, LiFeP0₄-based, LiNi0₂-based and LiMn₂0₄-based lithium ion batteries.

[00143] FIG. 12 shows the impedance spectrum and Nyquist plots of the

PVDF/PBAB/EC:PC composite electrolyte at room temperature. The diagram of the Nyquist plot includes two elements: a suppressed semicircle in the high frequency regime that corresponds to bulk resistance and a straight line in the lower frequency regime that corresponds to interfacial resistance controlled by the diffusion of the charged particles. This electrochemical behavior is typical for single ion conducting polymer electrolytes with the impedance accounting for both the bulk resistance and the interfacial resistance. Using the above equation, σ = L/(R*A), the ionic conductivity of the PVDF/PBAB/EC.PC membrane was calculated to be about 5.34 mS/cm, indicating that the composite membrane is also well suited for use in high power lithium ion batteries.

[00144] FIG. 13 shows the thermogravimetry (TG) curve of Poly (hydroquinone Borate) (PHB). The sample undergoes two separate decomposition steps. In the first step (below about 160 °C), a 5% weight loss was observed and can be attributed to the loss of absorbed water. In the second decomposition step, there is 40% weight loss observed at the temperature range of about 160 °C to about 479 °C, resulting from the degradation of the aromatic backbone of the polymer electrolyte. The remaining is lithium alcoholate, is stable up to about 600 °C. The compound displays moderate thermostability.

[00145] FIG. 14. is a field emission scanning electron micrograph (FE-SEM) and morphology of PHB. The micrograph shows that the particles of the sample are well- formed uniform particles with a size of about 1 μπι. 9

- 26 -

[00146] FIG. 15 shows the electrochemical stability of PHB. Linear sweep

voltammetry (LSV) was carried out of a PHB composite material to examine the electrochemical stability and the current-voltage response of the composite single ionic conductor polymer electrolyte. As shown in FIG. 15, the polyvinylidene

difluoride/PHB/ethylene carbonate : polycarbonate (PVDF/PHB/EC:PC) composite electrolyte possesses a current response of about 4.4 V versus Li/Li⁺. It is concluded that the PVDF/PHB/EC:PC composite electrolyte has suitable electrochemical properties for use in high-voltage lithium-based ion batteries such as LiCo0₂-based, LiFeP0₄-based, LiNi0₂-based and LiMii₂0₄-based lithium ion batteries.

[00147] FIG. 16 shows the impedance spectrum and Nyquist plots of the

PVDF/PHB/EC:PC composite electrolyte at room temperature. The diagram of the Nyquist plot includes two elements: a suppressed semicircle in the high frequency regime that corresponds to bulk resistance and a straight line in the lower frequency regime that corresponds to interfacial resistance controlled by the diffusion of the charged particles. This electrochemical behavior is typical for single ion conducting polymer electrolytes with the impedance accounting for both the bulk resistance and the interfacial resistance. Using the above equation, σ = L/(R*A), the ionic conductivity of the PVDF/PHB/EC:PC membrane was calculated to be about 6.61 mS/cm, indicating that the composite membrane is well suited for high power lithium ion batteries.

[00148J FIG. 17 shows the thermogravimetry (TG) curve of poly (4, 4'-biphenol borate) (PPB). The sample undergoes series of decomposition steps. In the first decomposition step (under about 150 °C), there is a weight loss of about 2% that can be attributed to the loss of absorbed water in the sample. In the second step, there is a weight loss of about 30% occurring between about 150 °C to about 540 °C, resulting from the degradation of the unreacted hydroxyl groups, the boron component, and the backbone of polymer. The remaining is lithium alcoholate is stable up to about 600 °C. PPB exhibits moderate thermostability.

[00149] FIG. 18 is a field emission scanning electron micrograph (FE-SEM) and morphology of PPB. FIG. 18 shows that the particles of the sample are well-formed strip shaped particles with a particle size of about 5 μηι x 2 μηι. [00150] FIG. 19 shows the electrochemical stability of PPB. Linear sweep voltammetry (LSV) was carried out of a PPB composite material to examine the electrochemical stability and the current-voltage response of the composite single ionic conductor polymer electrolyte. As shown in FIG. 19, the polyvinylidene

difluoride/PPB/ethylene carbonaterpolycarbonate (PVDF/PPB/EC:PC) composite electrolyte possesses a current response of about 4.5 V versus Li/Li⁺. It is concluded that the PVDF/PPB/EC:PC composite electrolyte has suitable electrochemical properties for use in high-voltage lithium-based ion batteries such as LiCo0₂-based, LiFeP0₄-based, LiNi0₂-based and LiMn₂0₄-based lithium ion batteries.

[00151] FIG. 20 shows the impedance spectrum and Nyquist plots of the

PVDF/PPB/EC:PC composite electrolyte at room temperature. The diagram of the Nyquist plot includes two elements: a suppressed semicircle in the high frequency regime that corresponds to bulk resistance and a straight line in the lower frequency regime that corresponds to interfacial resistance controlled by the diffusion of the charged particles. This electrochemical behavior is typical for single ion conducting polymer electrolytes with the impedance accounting for both the bulk resistance and the interfacial resistance. Using the above equation, σ = L/(R*A), the ionic conductivity of the PVDF/PHB/EC:PC membrane was calculated to be about 4.81 mS/cm, indicating that the composite membrane is well suited for use in high power lithium ion batteries

[00152] FIG. 21 shows the thermogravimetry (TG) curve of poly (4, 4'-biphenol borate) (PBB). The sample undergoes two steps of decomposition. In the first step (at about 260 °C), there is weight loss of about 5% that can be attributed to the degradation of the boron component. In the second step, another 7% weight loss is observed between about 350 °C to about 500 °C, resulting from the degradation of hydroxyl group. The remaining product is lithium 4, 4'-biphenolate. The compound displays good thermostability.

[00153] FIG. 22 is a field emission scanning electron micrograph (FE-SEM) and morphology of PBB. FIG. 22 shows that the particles of the sample are well-formed uniform particles with the size of about 50 nm.

[00154] FIG. 23 shows the electrochemical stability of PBB Linear sweep voltammetry (LSV) was carried out of a PBB composite material to examine the electrochemical stability and the current-voltage response of the composite single ionic conductor polymer electrolyte. As shown in FIG. 15, the polyvinylidene

difluoride/PBB/ethylene carbonate : polycarbonate (PVDF/PBB/EC:PC) composite electrolyte possesses a current response of about 4.7 V versus Li/Li⁺. It was concluded that the PVDF/PBB EC:PC composite electrolyte has suitable electrochemical properties for use in high-voltage lithium-based ion batteries such as LiCo0₂-based, LiFeP0₄-based, LiNi0₂-based and LiMn₂0₄-based lithium ion batteries.

[00155] FIG. 24 shows the impedance spectrum and Nyquist plots of the

PVDF/PBB/EC:PC composite electrolyte at room temperature. The diagram of the Nyquist plot includes two elements: a suppressed semicircle in the high frequency regime that corresponds to bulk resistance and a straight line in the lower frequency regime that corresponds to interfacial resistance controlled by the diffusion of the charged particles. This electrochemical behavior is typical for single ion conducting polymer electrolytes with the impedance accounting for both the bulk resistance and the interfacial resistance. Using the above equation, σ = L/(R*A), the ionic conductivity of the PVDF/PBB/EC:PC membrane was calculated to be about 1.38 mS/cm, indicating that the composite membrane is well suited for use in high power lithium ion batteries.

EXPERIMENTAL

[00156] Structures of these materials were characterized by Fourier Transform

Infrared spectroscopy (FTIR), carbon- 13 and boron- 11 ( 13 C and 11 B) nuclear magnetic spectroscopy (NMR), as well as GPC. The morphology and thermal and

electrochemical properties of these sp³ boron-based compounds are characterized via spectroscopic techniques. EXAMPLE 1: synthesis of poly (pyromellitic acid borate) (PPAB) electrolyte with a One-dimensional polymeric framework

Silylation of Pyromellitic acid:

[00157] Pyromellitic acid (1) and anhydrous 1 ,2-dichIoroethane (DCE) were placed in a flask under an atmosphere of argon. Hexamethyldisilane (HMDS) was then added and the resulting mixture was heated to 100°C and stirred until all of the acid was consumed (about 6 hrs). The solvent and the excess hexamethyldisilane were then removed under reduced pressure to provide the silylated intermediate (2). Ή NMR (CDC1₃): δ 7.96 ppm (2H, s), 0.39 ppm (18H, s).

Synthesis of Lithium Poly (Pyromellitic Acid Borate) (PPAB)

[00158] The silylated intermediate (2), lithium tetramethanolatoborate and a small amount of anhydrous N,N-Dimethylformamide (DMF) were placed in a flask and stirred under an argon atmosphere for 3 days. The crude product was recrystallized in DMF. The crystals were filtered, washed with acetonitrile to remove all impurities and dried under reduced pressure at 120 °C for 24 hours. PPAB was stored in a glove box under a dry argon atmosphere. ¹³C NMR (OM O-d6): δ 167.13, 69.13, 11.38 ppm; ⁿB NMR: δ 2.38 ppm. FT-IR (KBr, Avatar-37, 400-4000 cm^"1): 1722 cm^"1, 1408 cm^" ', 1365 cm^"',1301 cm^"1, 1261 cm^"1, 1116 cm^"1, 983.7cm^"1, 925.8 cm^"1, 802.4 cm^"1, 763.8 cm^"1, 644.2 cm^"1, 435.9 cm^"1; M_n (GPC, H₂0)= 7360 g/mol, M_w/M_n=1.21; M_w= 0.89 x 10⁴. EXAMPLE 2: Synthesis of Poly (Terephthalic Acid Borate) (PTAB) with a Dimensional Polymeric Framework

Silylation of Terephthalic acid:

[00159] Terephthalic acid (3) and anhydrous 1 ,2-dichloroethane (DCE) were placed in a flask under an atmosphere of argon. Hexamethyldisilane (HMDS) was then added and the resulting mixture was heated to 100°C and stirred until all of the acid was consumed (about 6 hrs). The solvent and the excess hexamethyldisilane were then removed under reduced pressure to provide the silylated intermediate (4). Ή NMR (CDC1₃): δ 8.83 ppm (4H, s), 0.42 ppm (18H, s).

Synthesis of Lithium Poly (T rephthalic Acid Borate) (PTAB)

[00160] The silylated intermediate (4), lithium tetramethanolatoborate and a small amount of anhydrous N,N-Dimethylformamide (DMF) were placed in a flask and stirred under an argon atmosphere at 50 °C for 3 days. The crude product was recrystallized in DMF. The crystals were filtered, washed with acetonitrile to remove all impurities and dried under reduced pressure at 120 °C for 24 hours. PTAB was stored in a glove box under a dry argon atmosphere. ¹³C-NMR (fyO-d²) δ 175.23, 138.60, 128.59 ppm; ¹ Έ NMR (D₂0, relative to BF₃,OEt₂): δ 0.80 ppm; FT-IR ( Br, Avatar-37, 400-4000 cm^"'): vl575.8 cm^"1, 1502.5 cm^"1, 1452.4 cm^"1, 1396.5 cm^"1, 1305.8 cm^"1, 1095.6 cm^"1, 1018.4 cm^"1, 829.4 cm^"1, 758.0 cm^'1, 528.5 cm^"1, 470.6 cm^"1; M_n(GPC, H₂0)=3755 g/mol, M_w/M_n=3.52; M_w= 1.32 x 10⁴. EXAMPLE 3: Poly(l,2,3,4-Butanetetracarboxylic Acid Borate) (PBAB) with a One- Dimensional Polymeric Framework

Silylation ofl, 2, 3, 4-Butanetetracarboxylic acid:

[00161] 1, 2, 3, 4-Butanetetracarboxylic acid (5) and anhydrous 1 ,2-dichloroethane (DCE) were placed in a flask under an atmosphere of argon. Hexamethyldisilane (HMDS) was then added and the resulting mixture was heated to 100°C and stirred until all of the acid was consumed (about 6 hrs). The solvent and the excess

hexamethyldisilane were then removed under reduced pressure to provide the silylated intermediate (6). Ή NMR (CDC1₃): 53.80 (2H, d), 63.12 (2H, d), 60.20 (18H, s).

Synthesis of Lithium Poly (1 ,2, 3, 4-Butanetetracarboxylic Borate) (PBAB)

[00162] The silylated intermediate (6), lithium tetramethanolatoborate and a small amount of anhydrous Acetonitrile (ACN) were placed in a flask and stirred under an argon atmosphere at 45 °C for 1 day. The crude product was recrystallized in DMF. The crystals were filtered, washed with acetonitrile to remove all impurities and dried under reduced pressure at 120 °C for 24 hours. PBAB was stored in a glove box under a dry argon atmosphere. ^{l l}B NMR (D₂0, relative to BF₃,OEt₂): δ 0.42. FT-IR (KBr, Avatar-37, 400~4000cm^"1): v3440 cm^"1, 2851 cm^"1, 1674 cm^"1, 1558 cm^"1, 1423 cm^"1, 1310 cm^"1, 1252 cm^"1, 1221 cm^"1, 1180 cm^"1, 1013 cm^"1, 904.6 cm^"1, 871.8 cm^"1, 810.1 cm^"1, 659.7 cm^"1, 594.1 cm^"1, 526.6cm^"1; M_n (GPC, H₂0) =29441 g mol^"1, M_w/M_n=1.16; M_w=3.42 x l0⁴. EXAMPLE 4: Poly (Hydroquinone Borate) (PHB) with a Three-Dimensional

Polymeric Framework

Synthesis of Lithium Poly (1,2,3,4-Butanetetracarboxylic Borate) (PHB)

[00163] Hydroquinone (7), lithium tetramethanolatoborate and a small amount of anhydrous Ν,Ν-Dimethylformamide (DMF) were placed in a flask and stirred under an argon atmosphere 3 days. The crude product was recrystallized in DMF. The crystals were filtered, washed with acetonitrile to remove all impurities and dried under reduced pressure at 120 °C for 24 hours. PHB was stored in a glove box under a dry argon atmosphere. ^lB NMR (D₂0, relative to BF₃,OEt₂): d 7.92; FT-IR (KBr, Avatar-37, 400~4000cm^"'): v3427 cm^"1; 1636 cm^"1, 1506, 1356; 1356 crn ',51202 cm^"1, 1015 cm^" '; The v_B-o peak of 1356 cm^"1 successfully confirms the formation of polymer electrolyte salt; M_n (GPC, H₂0) =27829 g mol^"1, M_w/M„=1.32; M_w=3.68 x 10⁴.

EXAMPLE 5: Synthesis of Lithium Poly (Phloroglucinol borate) (PPB) With a

Dimensional Polymeric Framework

[00164] Phloroglucinol (8), lithium tetramethanolatoborate and a small amount of anhydrous Ν,Ν-Dimethylformamide (DMF) were placed in a flask and stirred under an argon atmosphere 3 days. The crude product was recrystallized in DMF. The crystals were filtered, washed with acetonitrile to remove all impurities and dried under reduced pressure at 120 °C for 24 hours. PPB was stored in a glove box under a dry argon atmosphere. ⁿB NMR (D₂0, relative to BF₃,OEt₂): d 8.16; FT-IR (KBr, Avatar-37, 400~4000cm^"1): v3410 cm-¹; 1522 cm^"1; 1379 cm^"1; 1254 cm^"1, 1003 cm^"1; The v_B-0 peak of 1379 cm^"1 successfully confirms the formation of polymer electrolyte salt; M„

(GPC, H₂0) =18480g mol^"1, M_w/M_n=1.35; M_w=2.50 x 10⁴.

EXAMPLE 6: Synthesis of Lithium Poly (4, 4 '-Biphenol Borate) (PBB) with a

[00165] 4, 4'-biphenol (9), lithium tetramethanolatoborate and a small amount of anhydrous N,N-Dimethylformamide (DMF) were placed in a flask and stirred under an argon atmosphere 3 days. The crude product was recrystallized in DMF. The crystals were filtered, washed with acetonitrile to remove all impurities and dried under reduced pressure at 120 °C for 24 hours. PBB was stored in a glove box under a dry argon atmosphere. ^UB NMR (D₂0, relative to BF₃,OEt₂): d 4.74; FT-IR (KBr, Avatar-37, 400~4000cm^'1): v3441 cm^'1, 1622 cm^"1, 1385 cm^"1; 1385 cm^"1, 1018 cm^"1; The broad VB-O peak of 1385 cm^"1 successfully conforms the formation of polymer electrolyte salt; M_n (GPC, H₂0) =16355g mol^"1, M_w/M_n=2.13; M_w=3.48 x 10⁴.

EXAMPLE 7: Preparation of Boron-based Single-Ion Polymer Electrolyte Composite Film

[00166] A boron-based single-ion polymer electrolyte and poly(vinylidene fiuoride- co-hexafluoropropylene (PVDF-HFP) in 3:1 ratio of polymer electrolyte to PVDF-HFP were dissolved in Ν,Ν-dimethylforamide at about 75-80 °C. The resulting solution was then casted onto a glass plate and the solvent was slowly evaporated by heating the mixture to 80 °C. The remaining solvent was then removed by placing the sample under vacuum and heating to 80 °C for 2 days. Once dry, the polymer electrolyte composites was transferred into a glove box and immersed in a 1 :1 of polycarbonate and ethylene carbonate solution.

[00167] Table 1. Molecular weight of polymer electrolytes by GPC analysis.

Mn(*10⁴) Mw(xl0⁴) Mw/Mn

LiPHB 2.78 3.68 1.32

LiPPB 1.85 2.50 1.35

LiPBB 1.64 3.48 2.13

LiPBAB 2.94 3.42 1.16

PPAB 0.74 0.89 1.21

PTAB 0.38 1.32 3.52

[00168] Table 2 Measured values for the corresponding calculated values of lithium ion transference numbers (fi )- tu

Electrolytes I_s V - I_mR.)

!_a (AV - l_sR_s)

LiPHB 0.93

LiPPB 0.91

LiPBB 0.93

LiPBAB 0.87

LiPPAB 0.89

LiPTAB 0.90

[00169] The teachings of all patents, published applications and references cited herein are incorporated by reference in their entirety.

[00170] While this invention has been particularly shown and described with references to example embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.

Claims

claimed is:

A sp3 boron-based single-ion conducting polymer electrolyte, comprising a reaction product obtained by reacting:

an alkali metal alkoxy orthoborate salt; and

an anion stabilizing monomer,

wherein the anion stabilizing monomer comprises an aromatic carboxylic acid, an aliphatic carboxylic acid, or an aromatic phenol; and

wherein the average molecular weight Mw of the sp3 boron-based single-ion conducting polymer electrolyte is between about 5,000 to about 100,000.

The sp3 boron-based single-ion conducting polymer electrolyte of Claim 1 represented by Structural Formula (I):

wherein:

M is H or an alkali metal;

can be a single or double bond;

each Ri and R₂ are independently H, halogen, an optionally substituted (C1-C4) alkyl, an optionally substituted (C1-C4) alkoxy, an optionally substituted (Cl- C4) alkyl amino, an optionally substituted (C1-C4) dialkyl amino, an optionally substituted (Cl-C4)acyl, or an optionally substituted (C1-C4)NR₃C(0), wherein the optional substituents are each independently H, halogen, (C1-C4) alkyl, (C1-C4) alkoxy, (C1-C4) halo alkyl, (C1-C4) haioalkoxy, (C1-C4) alkyl amino, (C 1 -C4) dialkyl amino, or (C 1 -C4)acyl; or Ri and R₂ together form a (C6-C10) aryl ring optionally substituted with 1 to 4 R4;

R₃ and R₅ are each independently H or an optionally substituted (C1-C4) alkyl, wherein the optional substituents on (C1-C4) alkyl are each

independently H, halogen, or (C1-C4) alkoxy;

R₄ is each independently H, halogen, an optionally substituted (C1-C4) alkyl, an optionally substituted (C1-C4) alkoxy, an optionally substituted (Cl- C4) alkyl amino, an optionally substituted (C1-C4) dialkyl amino, an optionally substituted (Cl-C4)acyl, or an optionally substituted (C1-C4)NR₅C(0), wherein the optional substituents are each independently H, halogen, (C1-C4) alkyl, (C1-C4) alkoxy, (C1-C4) halo alkyl, (C1-C4) haloalkoxy, (C1-C4) alkyl amino, (C1-C4) dialkyl amino, or (Cl-C4)acyl; and

n is an integer from 1-100.

3. The sp3 boron-based single-ion conducting polymer electrolyte of Claim 2, wherein M is selected from lithium, sodium or potassium.

4. The sp3 boron-based single-ion conducting polymer electrolyte of Claim 2, wherein Ri and R₂ are H.

5. The sp3 boron-based single-ion conducting polymer electrolyte of Claim 2, wherein Ri and R₂ form a (C6) aryl ring optionally substituted with 1 to 4 R₄.

6. The sp3 boron-based single-ion conducting polymer electrolyte of Claim 2, wherein the n is selected to provide a polymer with a weight average molecular weight in the range of approximately 8,000 to about 40,000.

7. The sp3 boron-based single-ion conducting polymer electrolyte of Claim 1

represented by Structural Formula (II):

wherein:

M is H or an alkali metal;

each X is independently O or C(O);

each R] is independently H, halogen, an optionally substituted (C1-C4) alkyl, an optionally substituted (C 1-C4) alkoxy, an optionally substituted (Cl- C4) alkyl amino, an optionally substituted (C1-C4) dialkyl amino, an optionally substituted (Cl-C4)acyl, or an optionally substituted (C1-C4)NR₃C(0), wherein the optional substituents are each independently H, halogen, (C1-C4) alkyl, (C1-C4) alkoxy, (C1-C4) halo alkyl, (C1-C4) haloalkoxy, (C1-C4) alkyl amino, (C1-C4) dialkyl amino, or (Cl-C4)acyl;

each R₂ is independently H, halogen, an optionally substituted (C1-C4) alkyl, an optionally substituted (C1-C4) alkoxy, an optionally substituted (Cl- C4) alkyl amino, an optionally substituted (C1-C4) dialkyl amino, an optionally substituted (Cl-C4)acyl, or an optionally substituted (C1-C4)NR₄C(0), wherein the optional substituents are each independently H, halogen, (C1-C4) alkyl, (C1-C4) alkoxy, (C1-C4) halo alkyl, (C1-C4) haloalkoxy, (C1-C4) alkyl amino, (C1-C4) dialkyl amino, or (Cl-C4)acyl;

R₃, R4 and R₆ are each independently H or an optionally substituted (Cl- C4) alkyl, wherein the optional substituents on (C1-C4) alkyl are each independently H, halogen, or (C1-C4) alkoxy;

L is a bond or a (C6-C10) aryl ring substituted with 1 to 4 R₅;

each R₅ is independently H, halogen, an optionally substituted (C1-C4) alkyl, an optionally substituted (C1-C4) alkoxy, an optionally substituted (Cl- C4) alkyl amino, an optionally substituted (C1-C4) dialkyl amino, an optionally substituted (Cl-C4)acyl, or an optionally substituted (C1-C4)NR₆C(0), wherein the optional substituents are each independently H, halogen, (C1-C4) alkyl, (C1-C4) alkoxy, (C1-C4) halo alkyl, (C1-C4) haloalkoxy, (C1 -C4) alkyl amino, (C1-C4) dialkyl amino, or (Cl-C4)acyl;

each i and m₂ is independently an integer from 1 to 4 ; and

n is an integer from 1-100.

8. The sp3 boron-based single-ion conducting polymer electrolyte of Claim 7, wherein M is selected from lithium, sodium or potassium.

9. The sp3 boron-based single-ion conducting polymer electrolyte of Claim 7, wherein Ri and R₂ are H and L is a bond.

10. The sp3 boron-based single-ion conducting polymer electrolyte of Claim 7, R_\ and R₂ are H, and L is a (C6)aryl ring optionally substituted with 1 to 4 R₅.

11. The sp3 boron-based single-ion conducting polymer electrolyte of Claim 7, wherein the n is selected to provide the polymer with a weight average molecular weight in the range of approximately 8,000 to about 40,000.

12. The sp3 boron-based single-ion conducting polymer electrolyte of Claim 1 represented by Structural Formula (III):

wherein:

M is H or an alkali metal;

each R_\ is independently H, halogen, an optionally substituted (C1-C4) alkyl, an optionally substituted (C1-C4) alkoxy, an optionally substituted (Cl- C4) alkyl amino, an optionally substituted (C1-C4) dialkyl amino, an optionally substituted (Cl-C4)acyl, or an optionally substituted (C1-C4)NR₃C(0), wherein the optional substituents are each independently H, halogen, (C1-C4) alkyl, (C1-C4) alkoxy, (C1-C4) halo alkyl, (C1-C4) haloalkoxy, (C1-C4) alkyl amino, (C1-C4) dialkyl amino, or (Cl-C4)acyl;

each R-2 is independently H, halogen, an optionally substituted (C1-C4) alkyl, an optionally substituted (C1-C4) alkoxy, an optionally substituted (Cl- C4) alkyl amino, an optionally substituted (C1-C4) dialkyl amino, an optionally substituted (Cl-C4)acyl, or an optionally substituted (C 1 -C4)NR₄C(0), wherein the optional substituents are each independently H, halogen, (C1-C4) alkyl, (C1-C4) alkoxy, (C1-C4) halo alkyl, (C1-C4) haloalkoxy, (C1-C4) alkyl amino, (C1-C4) dialkyl amino, or (Cl-C4)acyl;

R₃ and Rj are each independently H or an optionally substituted (C1-C4) alkyl, wherein the optional substituents on (C1-C4) alkyl are each

independently H, halogen, or (C1-C4) alkoxy;

each mi and m₂ is independently an integer from 1 to 4 ; and n is an integer from 1-100.

13. The sp3 boron-based single-ion conducting polymer electrolyte of Claim 11, wherein M is selected from lithium, sodium or potassium.

14. The sp3 boron-based single-ion conducting polymer electrolyte of Claim 11 , wherein the R_\ and R₂ are H.

15. The single-ion conducting polymer electrolyte of Claim 11 , wherein the n is selected to provide a polymer with a weight average molecular weight in the range of approximately 8,000 to about 40,000. The single-ion conducting polymer electrolyte of Claim 1 , wherein alkali metal alkoxy orthoborate salt is lithium tetramethanolatoborate.

A sp3 boron-based single-ion conducting polymer electrolyte of Claim 1 represented by any one of the following structures:

wherein the n is selected to provide a polymer with a weight average molecular weight in the range of about 8,000 to about 40,000.

The sp3 boron-based single-ion conducting polymer electrolyte of Claim 1 , wherein the anion stabilizing monomer comprises any one of the following Structural Formulae:

wherein:

R], R₂, and R₅ are each independently H, halogen, an optionally substituted (C1-C4) alkyl, an optionally substituted (C1-C4) alkoxy, an optionally substituted (C1-C4) alkyl amino, an optionally substituted (C1-C4) dialkyl amino, an optionally substituted (Cl-C4)acyl, or an optionally substituted (C1-C4)NR₃C(0), wherein the optional substituents are each independently H, halogen, (C1-C4) alkyl, (C1-C4) alkoxy, (C1-C4) halo alkyl, (C1-C4) haloalkoxy, (C1 -C4) alkyl amino, (C1-C4) dialkyl amino, or (Cl- C4)acyl;

R , R , and R₇ are each independently H, halogen, an optionally substituted (C1 -C4) alkyl, an optionally substituted (C1-C4) alkoxy, an optionally substituted (C1 -C4) alkyl amino, an optionally substituted (C1 -C4) dialkyl amino, an optionally substituted (C l-C4)acyl, or an optionally substituted (Cl -C4)NRgC(0), wherein the optional substituents are each independently H, halogen, (C1 -C4) alkyl, (C1 -C4) alkoxy, (C1-C4) halo alkyl, (C1-C4) haloalkoxy, (C1 -C4) alkyl amino, (C1-C4) dialkyl amino, or (Cl - C4)acyl;

each R₉ and R₁₀ are independently H, halogen, an optionally substituted (C1 -C4) alkyl, an optionally substituted (C1 -C4) alkoxy, an optionally substituted (C1-C4) alkyl amino, an optionally substituted (C 1-C4) dialkyl amino, an optionally substituted (C l-C4)acyl, or an optionally substituted (Cl- C4)NRi iC(0), wherein the optional substituents are each independently H, halogen, (C1 -C4) alkyl, (C1-C4) alkoxy, (C1-C4) halo alkyl, (C1 -C4) haloalkoxy, (C1 -C4) alkyl amino, (C1 -C4) dialkyl amino, or (Cl -C4)acyl;

R3, R₈, and Rn are each independently H or an optionally substituted (C1 -C4) alkyl, wherein the optional substituents on (C1 -C4) alkyl are each independently H, halogen, or (C1-C4) alkoxy;

mi is an integer from 1 to 2;

each m₂, m₄, m₅, and m₆ is independently an integer from 1 to 4; and m₇ is an integer from 1 to 3.

19. A method for synthesizing a sp3 boron-based single-ion conducting polymer electrolyte, comprising:

a) heating a mixture of a carboxylic acid and a silylating agent to form a silylated carboxylic acid intermediate; and

b) heating a mixture of the silylated carboxylic acid intermediate with a metal alkoxy orthoborate salt to form a sp3 boron-based single-ion conducting polymer electrolyte.

20. The method of Claim 18, wherein the silylating agent is hexamethyldisiloxane and the metal alkoxy orthoborate salt is lithium tetramethanolatoborate.

21. A method for synthesizing a sp3 boron-based single-ion conducting polymer electrolyte, comprising: heating a mixture of an alcohol and an alkoxy orthoborate salt to form a sp3 boron-based single-ion conducting polymer electrolyte.

22. A battery, comprising: a sp3 boron-based single-ion conducting polymer electrolyte of Claim 1.