U.S. patent application number 15/332684 was filed with the patent office on 2017-07-13 for solid-phase magnesium boranyl electrolytes for a magnesium battery.
The applicant listed for this patent is Karlsruhe Institute of Technology, Toyota Motor Engineering & Manufacturing North America, Inc.. Invention is credited to Maximilian Fichtner, Fuminori Mizuno, Rana Mohtadi, Oscar Tutusaus, Zhiron Zhao-Karger.
Application Number | 20170200971 15/332684 |
Document ID | / |
Family ID | 59275133 |
Filed Date | 2017-07-13 |
United States Patent
Application |
20170200971 |
Kind Code |
A1 |
Mizuno; Fuminori ; et
al. |
July 13, 2017 |
SOLID-PHASE MAGNESIUM BORANYL ELECTROLYTES FOR A MAGNESIUM
BATTERY
Abstract
A solid-phase electrolyte is provided having a magnesium salt.
The salt contains a magnesium cation and a boron cluster anion and
can include an ether or other weakly-coordinating molecule in
dative interaction with the magnesium cation. A magnesium
electrochemical cell is also provided. The magnesium
electrochemical cell includes the solid-phase electrolyte, and also
includes an anode in ionic communication with the solid-phase
electrolyte. The anode, when charged, contains reduced
magnesium.
Inventors: |
Mizuno; Fuminori; (Ann
Arbor, MI) ; Mohtadi; Rana; (Northville, MI) ;
Tutusaus; Oscar; (Ann Arbor, MI) ; Fichtner;
Maximilian; (Eggenstein-Leopoldshafen, DE) ;
Zhao-Karger; Zhiron; (Eggenstein-Leopoldshafen, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Toyota Motor Engineering & Manufacturing North America,
Inc.
Karlsruhe Institute of Technology |
Erlanger
Eggeinstein-Leopoldshafen |
KY |
US
DE |
|
|
Family ID: |
59275133 |
Appl. No.: |
15/332684 |
Filed: |
October 24, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62277639 |
Jan 12, 2016 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01M 10/0562 20130101;
Y02E 60/10 20130101; H01M 2300/0068 20130101; H01M 10/054
20130101 |
International
Class: |
H01M 10/0562 20060101
H01M010/0562; H01M 10/054 20060101 H01M010/054 |
Claims
1. An electrochemical cell, comprising: an anode comprising
magnesium; a cathode; and a solid electrolyte in contact with at
least one of the anode and the cathode, the solid electrolyte
including a boron cluster salt having a formula:
MgE.sub.y(B.sub.nH.sub.n), MgE.sub.y[B.sub.mH.sub.(m+3)].sub.2, or
a combination thereof, wherein E is a magnesium ligand; y is within
a range of 0 through 6, inclusive; n is within a range of 6 through
12, inclusive; and m is within a range of 5 through 11,
inclusive.
2. The electrochemical cell as recited in claim 1, wherein y is
within a range of 1 through 6, inclusive.
3. The electrochemical cell as recited in claim 2, wherein E is an
ether.
4. The electrochemical cell as recited in claim 3, wherein E is any
of monoglyme, diglyme, triglyme, tetraglyme, polyethylene glycol
dimethyl ether, a poly(ethyleneoxide), and a combination
thereof.
5. The electrochemical cell as recited in claim 1, wherein the
boron cluster salt is any of MgE.sub.y(B.sub.10H.sub.10),
MgE.sub.y(B.sub.11H.sub.11), MgE.sub.y(B.sub.12H.sub.12),
MgE.sub.y(B.sub.11H.sub.14).sub.2, and a combination thereof.
6. A method for fabricating an electrochemical cell, the method
comprising: preparing a magnesium boron cluster salt by a process
that includes: contacting an organic boron cluster salt with a
magnesium salt in the presence of a weakly magnesium coordinating
solvent; and producing a precipitate that comprises the magnesium
boron cluster salt, the magnesium boron cluster salt having a
formula: MgE.sub.y(B.sub.nH.sub.n),
MgE.sub.y[B.sub.mH.sub.(m+3)].sub.2, or a combination thereof,
wherein E is a magnesium ligand; y is within a range of 0 through
6, inclusive; n is within a range of 6 through 12, inclusive; and m
is within a range of 5 through 11, inclusive; and placing the
magnesium boron cluster salt in ionic communication with an anode
and a cathode.
7. The method as recited in claim 6, wherein y is within a range of
1 through 6, inclusive.
8. The method as recited in claim 7, wherein E is an ether.
9. The method as recited in claim 8, wherein E is any of monoglyme,
diglyme, triglyme, tetraglyme, polyethylene glycol dimethyl ether,
a poly(ethyleneoxide), and a combination thereof.
10. The method as recited in claim 6, wherein the magnesium boron
cluster salt is any of .sub.y(B.sub.10H.sub.10),
MgE.sub.y(B.sub.11H.sub.11), MgE.sub.y(B.sub.12H.sub.12),
MgE.sub.y(B.sub.11H.sub.14).sub.2, and a combination thereof.
11. An electrochemical half-cell comprising: an electrode
configured to incorporate elemental magnesium during
electrochemical reduction, to release cationic magnesium during
electrochemical oxidation, or both; and a solid-phase magnesium
electrolyte in ionic communication with the electrode, the
solid-phase magnesium electrolyte comprising cationic magnesium and
at least one boron cluster anion including a boron cluster salt
having a formula: MgE.sub.y(B.sub.nH.sub.n),
MgE.sub.y[B.sub.mH.sub.(m+3)].sub.2, or a combination thereof,
wherein E is a magnesium ligand; y is within a range of 0 through
6, inclusive; n is within a range of 6 through 12, inclusive; and m
is within a range of 5 through 11, inclusive.
12. The electrochemical half-cell as recited in claim 11, wherein
the solid-phase magnesium electrolyte is substantially crystalline.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Application No. 62/277,639, filed Jan. 12, 2016, which is
incorporated by reference in its entirety.
TECHNICAL FIELD
[0002] The present disclosure is directed in part to an
electrochemical cell having a solid-phase magnesium electrolyte.
The present disclosure is also directed to a method for making such
an electrolytic cell.
BACKGROUND
[0003] Magnesium batteries have received significant attention as
potential replacements for lithium batteries due to their high
volumetric capacity, lack of dendrite formation, and the relative
inexpensiveness of magnesium. Discovery and development of suitable
electrolytes for magnesium batteries has proven challenging
however. Conventional inorganic magnesium salts have typically been
found incompatible with reversible magnesium deposition as they
tend to form an ion-blocking layer at the magnesium electrode
during their electrochemical reduction. On the other hand, organic
magnesium salts such as those derived from Grignard reagents have
been found to be highly corrosive, particularly toward non-noble
cathodes, possibly due to the presence of chloride co-anions.
[0004] Previous studies have shown that magnesium borohydride and
related magnesium boron cluster salts are effective as liquid
electrolytes in magnesium batteries, possessing high compatibility
with metal and the versatility to function with a variety of
magnesium-compatible cathodes. In virtually all such systems
studied to date, the electrolyte has been present as an ethereal
solution, as ethers are the only solvents known to be compatible
with magnesium.
[0005] The use of solid electrolytes generally has several
advantages relative to comparable liquid electrolytes, including
but not limited to a direct increase in energy density of the
battery. A small number of solvent-free, or solid magnesium
electrolytes have been reported. However, the known solid magnesium
electrolytes generally have insufficient magnesium mobility to be
practical in a magnesium battery at a desirable operating
temperature.
SUMMARY
[0006] The present disclosure provides an electrochemical cell
having a solid electrolyte, and a method for fabricating a
magnesium electrochemical cell having a solid-phase magnesium
electrolyte.
[0007] In an aspect, an electrochemical cell is provided having an
anode and a cathode. The electrochemical cell further includes a
solid electrolyte in contact with at least one of the anode and the
cathode, the solid electrolyte including a boron cluster salt
having a formula:
MgE.sub.y(B.sub.nH.sub.n),
MgE.sub.y[B.sub.mH.sub.(m+3)].sub.2, or
a combination thereof, wherein E is a magnesium ligand; y is within
a range of 0 through 6, inclusive; n is within a range of 6 through
12, inclusive; and m is within a range of 5 through 11,
inclusive.
[0008] In another aspect, a method for fabricating an
electrochemical cell is provided. The method includes a step of
preparing a magnesium boron cluster salt by a process that
includes: (i) contacting an organic boron cluster salt with a
magnesium salt in the presence of a solvent or mixture of solvents;
and (ii) producing a precipitate that comprises the magnesium boron
cluster salt. Or alternatively, the boron cluster salt mixture is
prepared as described in US patent application no. US20140154592
A1, by Mohtadi et. al. The magnesium boron cluster salt has a
formula:
MgE.sub.y(B.sub.nH.sub.n),
MgE.sub.y[B.sub.mH.sub.(m+3)].sub.2, or
a combination thereof, wherein E is a magnesium ligand; y is within
a range of 0 through 6, inclusive; n is within a range of 6 through
12, inclusive; and m is within a range of 5 through 11, inclusive.
The method additionally includes a step of placing the magnesium
boron cluster salt in ionic communication with an anode and a
cathode.
[0009] In yet another aspect, an electrochemical half-cell is
disclosed, having an electrode configured to absorb elemental
magnesium during electrochemical reduction, to release cationic
magnesium during electrochemical oxidation, or both. The
electrochemical half-cell further has a solid-phase magnesium
electrolyte in ionic communication with the electrode, the
solid-phase magnesium electrolyte comprising cationic magnesium and
at least one boron cluster anion.
[0010] These and other features of the electrochemical cell having
a solid-phase magnesium electrolyte, and the method for making the
same, will become apparent from the following detailed description
when read in conjunction with the figures and examples, which are
exemplary, not limiting.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] For a better understanding of the processes and devices
having a solid-phase magnesium electrolyte, with regard to the
particular variations and examples discussed herein, reference is
made to the accompanying figures, in which:
[0012] FIG. 1 is an Arrhenius plot showing the conductivity of the
magnesium boron cluster mixture: Mg(diglyme)B.sub.12H.sub.12,
Mg(diglyme)B.sub.11H.sub.11, and Mg(diglyme)B.sub.11H.sub.14;
[0013] FIG. 2 is a plot of conductivity of the magnesium boron
cluster Mg(diglyme)B.sub.12H.sub.13 as a function of
temperature;
[0014] FIG. 3 shows Magic Angle Spinning Nuclear Magnetic Resonance
(MAS-NMR) .sup.25Mg spectra of Mg(tetraglyme)B.sub.12H.sub.12, with
a comparison to Chevrel phase MgMo.sub.6S.sub.8 as a reference
spectrum; and
[0015] FIG. 4 is a flow-chart of a method for fabricating an
electrochemical cell.
DETAILED DESCRIPTION
[0016] The present disclosure provides a magnesium electrochemical
cell having a solid electrolyte, and a method for making the same.
The solid electrolyte utilizes any of a number of magnesium salts
that has excellent anodic compatibility with magnesium metal,
including high coulombic efficiency across a substantial electric
potential window for many charge-discharge cycles. Due to the
exclusion of solvent in liquid form, the solid electrolyte
possesses excellent physicochemical stability, including an absence
of volatility, as well as appreciable energy density. Further, it
has been discovered that the solid electrolyte made in accordance
with the present teachings has the highest conductivity as compared
to known solid magnesium electrolyte.
[0017] The solid electrolyte, as employed in the presently
disclosed electrochemical cell and method for making the same,
generally includes cationic magnesium and a boron cluster anion,
the magnesium can optionally be coordinated by at least one ether
(in some instances a multidentate ether) or other weakly
coordinating ligand. The solid electrolyte, such as those produced
within the context of the presently disclosed method, remains solid
up to temperatures higher than any typical magnesium battery
operating temperature, and thus will be produced and used as a
solid-phase magnesium electrolyte for a magnesium battery. The
solid electrolyte of the present disclosure possesses magnesium
mobility which makes it appropriate for use as magnesium
electrolyte.
[0018] Accordingly, provided herein is an electrochemical cell that
includes an anode; a cathode; and a solid electrolyte in contact
with at least one of the anode and the cathode. In general, the
solid electrolyte will contain a salt having at least one magnesium
cation (Mg.sup.2+) and at least boron cluster anion per
stoichiometric unit. In some instances, the solid electrolyte will
comprise a magnesium boron cluster salt having a formula of:
MgE.sub.y(B.sub.nH.sub.n), Formula I
MgE.sub.y[B.sub.mH.sub.(m+3)].sub.2, or Formula II
a combination thereof, wherein E is a magnesium ligand; y is within
a range of 0 through 6, inclusive; n is within a range of 6 through
12, inclusive; and m is within a range of 5 through 11, inclusive.
It is to be appreciated that the solid electrolyte can optionally
include multiple species selected from Formula I, Formula II, or
both.
[0019] The terms "solid electrolyte" and "solid-phase electrolyte",
as used herein, generally conform to the standard meaning of the
term "solid", as opposed to liquid, gas, solution, etc. In some
aspects, a solid electrolyte can be an electrolyte in which neither
magnesium cations nor boron cluster anions undergo bulk Brownian
motion. In some aspects, a solid electrolyte can be an electrolyte
in which boron cluster anions undergo neither bulk Brownian motion
nor bulk movement directed by an electric field. In some aspects, a
solid electrolyte can be an electrolyte having substantially
crystalline bulk morphology or is amorphous.
[0020] It will be appreciated that a magnesium boron cluster salt
of Formula I generally includes a closo-borate anion having a
formal charge of -2. Non-limiting examples of such closo-borate
anions include (B.sub.10H.sub.10).sup.2-,
(B.sub.11H.sub.11).sup.2-, and (B.sub.12H.sub.12).sup.2-. It will
equally be appreciated that a magnesium boron cluster salt of
Formula II generally includes a nido-borate anion having a formal
charge of -1. Non-limiting examples of such nido-borate anions
include (B.sub.11H.sub.14).sup.-.
[0021] In some implementations in which the magnesium ligand, E, of
Formulae I and II is present (i.e. where y is greater than zero),
the magnesium ligand will be an ether, preferably a multidentate
ether. Non limiting examples include tetrahydrofuran (THF),
1,2-dimethoxyethane (glyme), bis(2-methoxyethyl) ether (diglyme),
triethylene glycol dimethyl ether (triglyme), tetraethylene glycol
dimethyl ether (tetraglyme), a polyethylene glycol dimethyl ether,
and a poly(ethyleneoxide). It is to be appreciated that, while
Formulae I and II suggest the presence of a single species of
magnesium ligand, in different variations the magnesium ligand,
when present, can include any of: a combination of different
ethers; one or more non-ethers, and a combination of ethers and
non-ethers.
[0022] Solid electrolytes of the present disclosure possess
magnesium mobility, as determined from conductivity measurements.
It can be stated as a general approximation that, in order to be
effective in an electrochemical cell, a solid magnesium electrolyte
should possess conductivity of at least 10.sup.-6 milliSiemens per
centimeter (mS/cm).
[0023] FIG. 1 shows an Arrhenius plot, having conductivity plotted
logarithmically vs. inverse temperature, for a solid electrolyte
including a mixture of Mg(diglyme)B.sub.12H.sub.12,
Mg(diglyme)B.sub.11H.sub.11, and Mg(diglyme)B.sub.11H.sub.14. As
shown in FIG. 1, the exemplary solid electrolyte has a conductivity
of .about.10.sup.-4 mS/cm at 25.degree. C. and .about.10.sup.-3
mS/cm at 60.degree. C. As previous magnesium solid electrolytes
require a temperature of 150.degree. C. to achieve 10.sup.-3 mS/cm,
this result represents a 60% decrease in the required operating
temperature to achieve a desirable conductivity.
[0024] FIG. 2 shows conductivity as a function of temperature for a
solid-phase electrolyte having Mg(diglyme)B.sub.12H.sub.12. As
shown in FIG. 2, this exemplary solid-phase electrolyte achieves
conductivity of 10.sup.-3 mS/cm at 45.degree. C., representing a
70% reduction in required operating temperature relative to
previous magnesium solid-phase electrolytes. Referring now to FIG.
3, magic angle spinning nuclear magnetic resonance (MAS-NMR)
experiments was performed to further support the finding of high
magnesium cation mobility within the disclosed solid-phase
electrolyte. Chevrel phase Mg.sub.xMo.sub.6S.sub.8, a common
magnesium cathode material, was examined as an exemplary
high-conductivity material.
[0025] Due to the large nuclear quadrupole couplings, the
line-widths of .sup.25Mg resonances are normally in the range of
MHz. In FIG. 3, narrow line-widths in the range of kHz with the
magnesiated Chevrel phase Mg.sub.xMo.sub.6S.sub.8, and
Mg(tetraglyme)B.sub.12H.sub.12, which indicate the hopping
frequency mobility of the magnesium cations within the lattices. In
addition, relaxation time of less than one second was required in
the Ti measurements for these samples, thus again supporting a high
mobility of the Mg cation in Mg(tetraglyme)B.sub.12H.sub.12.
[0026] An electrochemical cell according to the present disclosure
and having a solid-phase electrolyte that includes a magnesium
boron cluster salt will, in many implementations, be a magnesium
battery wherein a reduction/oxidation reaction according to the
following reaction occurs in at least one half-cell:
Mg.sup.0Mg.sup.2++2e.sup.-
[0027] In many implementations, the electrochemical cell will be a
secondary battery or a subunit of a secondary battery. In such
implementations, it is to be understood that the term "anode" as
used herein refers to an electrode at which magnesium oxidation
occurs during device discharge and at which magnesium reduction
occurs during device charge. Similarly, it is to be understood that
the term "cathode" refers in such implementations to an electrode
at which a cathode material reduction occurs during device
discharge and at which a cathode material oxidation occurs during
device charge.
[0028] In such implementations, the anode can comprise any material
or combination of materials effective to participate in
electrochemical oxidation of magnesium during a device discharge.
Similarly, the anode can comprise any material or combination of
materials effective to participate in electrochemical reduction of
magnesium cations and to incorporate reduced magnesium during a
device charging event. In some implementations, the anode can
consist essentially of elemental magnesium (i.e. magnesium atoms
having no formal charge) or comprise at least one surface layer of
elemental magnesium. In other implementations, the anode can
comprise a magnesium-containing alloy and/or an insertion-type
magnesium electrode such as a tin or bismuth electrode, containing
magnesium in complex or alloy with other materials to the extent
the cell is charged.
[0029] The cathode can comprise any material or combination of
materials effective to participate in electrochemical insertion of
a cathode material during a device discharge. Similarly, the
cathode can comprise any material or combination of materials
effective to participate in electrochemical extraction of said
cathode material during a device charging event. In some
variations, the cathode material which is inserted at the cathode
during a device discharge and extracted from the cathode during
device charging event can comprise magnesium. Suitable but
non-exclusive examples of cathode materials can include a Chevrel
phase molybdenum composition such as Mo6S8, FeSiO4 (reversibly
MgFeSiO.sub.4), MnO.sub.2, MgFePO.sub.4, sulfur, organosulfur
compounds, an organic cathode materials such as
poly(2,2,6,6-tetramethyl-piperidinyl-1-oxy-4-yl methacrylate)
(PTMA), air, or any other suitable materials.
[0030] The electrochemical cell can additionally include at least
one external conductor, configured to enable electrical
communication between the anode and the cathode. In a simple
implementation, the at least one external conductor can be a single
conductor such as a wire connected at one end to the anode and at
an opposite end to the cathode. In other implementations, the at
least one external conductor can include a plurality of conductors
putting the anode and the cathode in electrical communication with
a power supply device configured to apply an electric potential to
the electrochemical cell during a charging event, with other
electrical devices situated to receive power from the
electrochemical cell, or both.
[0031] It is to be appreciated that an electrochemical cell of the
present disclosure will include at least one electrochemical
half-cell that includes an electrode and a solid-phase electrolyte
in ionic communication with the electrode. The solid-phase
electrolyte is as described above, and the electrode can be any
electrode configured to incorporate elemental magnesium during an
electrochemical reduction, to release cationic magnesium during an
electrochemical oxidation, or both. In general, the electrode of
the electrochemical half-cell can be either an anode or a cathode
as described above, including any of the anode or cathode materials
described above as non-limiting examples.
[0032] Also provided herein, and with reference to FIG. 4, is a
method 100 for preparing an electrochemical cell. The method 100
includes a step 108 of placing a solid-phase magnesium electrolyte
in ionic communication with at least one of an anode and a cathode.
The solid-phase magnesium electrolyte will generally be of the type
described above. The method 100 can additionally include a step 106
of preparing a solid-phase magnesium electrolyte of the type
described above. In some variations, the preparing step 106 can be
performed by a process that includes a step 102 of contacting an
organic boron cluster salt with a magnesium salt. In many
instances, the contacting step will be performed in the presence of
an ethereal solvent. The process for performing the preparing step
106 can further include a step 104 of producing a precipitate. The
precipitate produced by step 104 includes a magnesium boron cluster
salt, of the type described above.
[0033] In some variations, the precipitate produced by performance
of step 104 can be directly used as the solid-phase magnesium
electrolyte in step 108. In other variations, the precipitate can
be subjected to additional purification and/or processing steps
prior to use as the solid-phase magnesium electrolyte of step 108.
For example, magnesium boron cluster salt included in the
precipitate can be purified, such as by solvent extraction. The
magnesium boron cluster salt can also or alternatively be mixed
with an electrochemically inactive binder, such as polyvinylidene
fluoride, polytetrafluoroethylene, styrene butadiene rubber, and/or
polyimide.
[0034] It is to be appreciated that all ranges described in the
present disclosure are intended as being inclusive of the
endpoints. For example, a value described as being "within a range
of X through Y" can include the values X, Y, and values
intermediate to X an Y.
[0035] Various aspects of the present disclosure are further
illustrated with respect to the following Examples. It is to be
understood that these Examples are provided to illustrate specific
embodiments of the present disclosure and should not be construed
as limiting the scope of the present disclosure in or to any
particular aspect.
EXAMPLE 1
Electrolyte Synthesis
[0036] Preparation of magnesium dodecaborate tetraglyme
dichloromethane solvate: a solution of bis(tetrabutylammonium)
dodecaborate (1.0 g, 1.6 mmol) in anhydrous CH2C12 (40 mL) is added
anhydrous tetraglyme (40 mL) and set aside. This is termed
"Solution 1". In a separate container, a solution of magnesium
bis(trifluoromethanesulfonimide) (932 mg, 1.6 mmol) in anhydrous
tetraglyme (40 mL) is added to anhydrous CH2C12 (40 mL). This is
termed "Solution 2". Solution 2 is immediately added to Solution 1.
After 5 minutes stirring at room temperature, a white solid
precipitates out, resulting in a suspension. The suspension is
stirred for 24 hours and filtered. The solid is washed with
anhydrous tetraglyme/CH.sub.2C.sub.12 (1:1) (5 mL+10 mL+5 mL),
CH.sub.2C.sub.12 (2.times.5 mL), tetraglyme (2.times.5mL) and
Et.sub.2O (3.times.5 mL). The washed solid is dried under vacuum to
obtain 849 mg of a white solid.
EXAMPLE 2
Ionic Conductivity Measurements
[0037] About 50 mg of the solid from Example 1 is pressed between
two gold electrodes. The temperature is slowly elevated and the
conductivity is recorded. The result shown in FIG. 2 shows the
ionic conductivity of the magnesium cations function of the
temperature.
[0038] The foregoing description is merely illustrative in nature
and is in no way intended to limit the disclosure, its application,
or uses. As used herein, the phrase at least one of A, B, and C
should be construed to mean a logical (A or B or C), using a
non-exclusive logical "or." It should be understood that the
various steps within a method may be executed in different order
without altering the principles of the present disclosure; various
steps may be performed independently or at the same time unless
otherwise noted. Disclosure of ranges includes disclosure of all
ranges and subdivided ranges within the entire range.
[0039] The headings (such as "Background" and "Summary") and
sub-headings used herein are intended only for general organization
of topics within the present disclosure, and are not intended to
limit the disclosure of the technology or any aspect thereof. The
recitation of multiple embodiments having stated features is not
intended to exclude other embodiments having additional features,
or other embodiments incorporating different combinations of the
stated features.
[0040] As used herein, the terms "comprise" and "include" and their
variants are intended to be non-limiting, such that recitation of
items in succession or a list is not to the exclusion of other like
items that may also be useful in the devices and methods of this
technology. Similarly, the terms "can" and "may" and their variants
are intended to be non-limiting, such that recitation that an
embodiment can or may comprise certain elements or features does
not exclude other embodiments of the present technology that do not
contain those elements or features.
[0041] The broad teachings of the present disclosure can be
implemented in a variety of forms. Therefore, while this disclosure
includes particular examples, the true scope of the disclosure
should not be so limited since other modifications will become
apparent to the skilled practitioner upon a study of the
specification and the following claims. Reference herein to one
aspect, or various aspects means that a particular feature,
structure, or characteristic described in connection with an
embodiment is included in at least one embodiment or aspect. The
appearances of the phrase "in one aspect" (or variations thereof)
are not necessarily referring to the same aspect or embodiment.
[0042] While particular embodiments have been described,
alternatives, modifications, variations, improvements, and
substantial equivalents that are or may be presently unforeseen may
arise to applicants or others skilled in the art. Accordingly, the
appended claims as filed and as they may be amended, are intended
to embrace all such alternatives, modifications variations,
improvements, and substantial equivalents.
* * * * *