U.S. patent number RE37,700 [Application Number 09/334,740] was granted by the patent office on 2002-05-14 for ionically conductive polymer gels.
This patent grant is currently assigned to BTG International Limited. Invention is credited to James Eric McIntyre, Victor Rogers, Hugh Vyvyan St. Aubyn Hubbard, Ian Macmillan Ward.
United States Patent |
RE37,700 |
St. Aubyn Hubbard , et
al. |
May 14, 2002 |
Ionically conductive polymer gels
Abstract
A bulk ionically conductive polymer gel is prepared by
dissolving a salt such as lithium trifluoromethanesulphonate (which
would provide lithium ion conductors) in an organic compound such
as N-formylpiperidine. The organic compound dissolves the salt at
20.degree. C. but is not a solvent at 20.degree. C. though it is at
215.degree. C.) for polyethylene terephthalate. The last-named is a
crystallizable polymer which is added in a minor amount at a high
temperature to the other components and provides the required
mechanical rigidity for the product at lower temperatures.
Inventors: |
St. Aubyn Hubbard; Hugh Vyvyan
(Leeds, GB), McIntyre; James Eric (Harrogate,
GB), Rogers; Victor (Yoxall, GB), Ward; Ian
Macmillan (Bramhope, GB) |
Assignee: |
BTG International Limited
(London, GB)
|
Family
ID: |
10702426 |
Appl.
No.: |
09/334,740 |
Filed: |
June 17, 1999 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
196199 |
Feb 24, 1994 |
5460903 |
|
|
Reissue of: |
466129 |
Jun 6, 1995 |
05639574 |
Jun 17, 1997 |
|
|
Foreign Application Priority Data
Current U.S.
Class: |
429/300; 204/414;
252/500; 252/518.1; 252/62.2; 429/303; 429/306; 429/324; 429/328;
429/339; 429/341 |
Current CPC
Class: |
H01M
6/162 (20130101); H01M 6/164 (20130101); H01M
6/168 (20130101); H01M 6/181 (20130101); H01M
6/22 (20130101) |
Current International
Class: |
H01M
6/00 (20060101); H01M 6/22 (20060101); H01M
6/18 (20060101); H01M 6/16 (20060101); H01M
006/16 () |
Field of
Search: |
;252/62.2,500,518.1
;429/300,303,306,324,328,339,341 ;204/414 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Bell; Bruce F.
Attorney, Agent or Firm: Nixon & Vanderhye
Parent Case Text
This is a Rule 60 continuation of application Ser. No. 08/196,199,
filed 24 Feb. 1994 now U.S. Pat. No. 5,460,903.
Claims
What is claimed is:
1. An ionically conductive ion-containing gel having a bulk ionic
conductivity at 20.degree. C. and 10 kHz greater than 10.sup.31 4
Siemens/cm and a dynamic modulus at 10 Hz greater than 10.sup.3 Pa,
wherein the gel consists of a crystallizable polymer, wherein the
crystallizable polymer is present up to 50% by mass, and over 50%
by mass of an organic compound selected from the group consisting
of amides, sulphoxides and ethers, and a lithium salt with an anion
selected from the group consisting of Br, I, a pseudohalogen and a
perfluorinated alkyl carboxylate or sulphonate, said salt being
soluble in said organic compound at 20.degree. C. and dissolved
therein at a concentration greater than 4% by mass based on said
organic compound, wherein the said crystallizable polymer does not
dissolve in the said organic compound at 20.degree. C. but does
dissolve therein at some higher temperature.
2. A gel according to claim 1, wherein the crystallizable polymer
forms a coherent film or fiber.
3. A gel according to claim 1, wherein the crystallizable polymer
is a polyamide, polyester, polyether or substituted polyolefin.
4. A gel according to claim 3, wherein the crystallizable polymer
is poly(ethylene terephthalate), poly(1,4-butylene terephthalate),
poly(3-oxybutanoate), polyhydroxybutyric acid, poly(hexamethylene
adipamide), poly(metaxylylene adipamide), poly(m-phenylene
isophthalamide), poly (vinylidene fluoride), polyoxymethylene or
polyoxyethylene.
5. A gel according to claim 1, whose dynamic modulus at 10 Hz
exceeds 10.sup.4 Pa.
6. A gel according to claim 5, whose dynamic modulus at 10 Hz
exceeds 10.sup.5 Pa.
7. A gel according to claim 1, wherein the said organic compound is
a solvent for the crystallizable polymer at some temperature above
100.degree. C.
8. A gel according to claim 1, wherein the amide is a tertiary
amide.
9. A gel according to claim 1, wherein said compound is dimethyl
formamide, dimethyl acetamide, N-methyl-2-pyrrolidinone, N-formyl
piperidine, a dimethyl ether of diethylene glycol, triethylene
glycol or tetraethylene glycol, or dimethyl sulphoxide.
10. A method of making a gel, said gel being as defined in claim 1,
said method comprising the steps of:
forming a solution of a crystallizable polymer in an organic
compound at above 20.degree. C.;
incorporating a lithium salt beforehand, simultaneously or
afterwards; and
cooling the solution.
11. A method according to claim 10, wherein said solution is formed
at above 100.degree. C.
12. A method according to claim 11, wherein said solution is formed
at above 150.degree. C.
13. A galvanic cell having an electrolyte wherein the electrolyte
comprises a gel made by the method of claim 10.
14. A galvanic cell having an electrolyte wherein the electrolyte
comprises a gel according to claim 1..Iadd.
15. An ionically conductive ion-containing gel having a bulk ionic
conductivity at 20.degree. C. and 10 kHz greater than 10.sup.-4
Siemens/cm and a dynamic modulus at 10 Hz greater than 10.sup.4 Pa,
wherein the gel consists of a crystallizable polymer, wherein the
crystallizable polymer is present in an amount of 20 to 40% by
mass, and over 60% by mass of an organic compound or mixture of
organic compounds, and a lithium salt with a monovalent anion
selected from the group consisting of Br, I, a pseudohalogen a
perfluorinated alkyl carboxylate or sulphonate anion and a complex
inorganic monovalent anion, said salt being soluble in said organic
compound at 20.degree. C., and dissolved therein at a concentration
greater than 4% by mass based on said organic compound, wherein
said crystallizable polymer is a crystallizable halo substituted
polyolefin which does not dissolve in said organic compound or
mixture of organic compounds at 20.degree. C. but does dissolve
therein at some higher temperature..Iaddend..Iadd.
16. A gel as claimed in claim 15 wherein the gel comprises one said
organic compound..Iaddend..Iadd.
17. A gel as claimed in claim 15 wherein the crystallizable polymer
is a halo substituted polyvinylidene..Iaddend..Iadd.
18. A gel as claimed in claim 15 wherein the crystallizable polymer
is poly(vinylidene fluoride)..Iaddend..Iadd.
19. A gel as claimed in claim 15 wherein the salt is lithium
trifluoromethane sulphonate..Iaddend..Iadd.
20. A method of making a gel as defined in claim 15, said method
comprising the steps of:
forming a solution of crystallizable polymer in an organic compound
at above 20.degree. C.;
incorporating a lithium salt beforehand, simultaneously or
afterwards; and
cooling the solution..Iaddend..Iadd.
21. A method according to claim 20, wherein said solution is formed
at above 100.degree. C..Iaddend..Iadd.
22. A method according to claim 20, wherein said solution is formed
at above 150.degree. C..Iaddend..Iadd.
23. A galvanic cell having an electrolyte wherein the electrolyte
comprises a gel made by the method of claim 20..Iaddend..Iadd.
24. A galvanic cell having an electrolyte wherein the electrolyte
comprises a gel according to claim 15..Iaddend..Iadd.
25. A gel as claimed in claim 15 wherein said anion is selected
from the group consisting of SCN.sup.-, ClO.sub.4.sup.-,
HgI.sub.3.sup.-, BF.sub.4.sup.-, CF.sub.3 COO.sup.- and CF.sub.3
SO.sub.3.sup.-..Iaddend.
Description
This invention relates to bulk ionically conductive polymer gels
and their preparation, and to galvanic cells containing them.
BACKGROUND OF THE INVENTION
The most commonly used electrolytes are fluid liquids which
comprise solutions in a liquid solvent of solute ionic species.
Such fluid liquid electrolytes, on incorporation into a galvanic
cell, permit migration of ions between the electrodes of the cell
and, as a consequence, the provision of electric free energy to a
closed external circuit. Despite their widespread use, such
electrolytes nonetheless suffer from several disadvantages. Thus,
they are often corrosive, leading to leakage from cells and they do
not provide a firm barrier between the electrodes when required to
assist in stabilizing the inter-electrode distance and in
preventing physical loss of electrode material from the electrode
surface.
In order, in part, to overcome the disadvantages inherent in fluid
liquid electrolytes, particularly in relation to galvanic cells,
considerable effort has been expended in attempts to provide solid
or highly viscous polymeric electrolytes which contain salts which
display mobility, under appropriate conditions, of at least some of
the ionic species present. The solid polymeric electrolytes are
capable of acting in thin film form as electrode separators and in
solid-state cells can deform while maintaining good contact with
the electrodes, thus minimizing problems arising from mechanical
strain arising either from mechanical stresses during use or volume
changes during the charge/discharge cycle. A particular area of
importance is in cells that do not depend upon water as a component
of the electrolyte, such as lithium cells where water and other
materials capable of reacting with lithium are undesirable. The
potential uses for such materials are not limited to batteries but
include, inter alia, sensor devices and thermoelectric energy
convectors.
A prominent polymeric material for this purpose has been
poly(ethylene oxide) (PEO), in which certain salts are soluble and
can form complexes. The electrical and mechanical properties of
such polymer electrolyte materials, although encouraging, require
further enhancement before commercialisation can be envisaged.
Improvements in the properties have been obtained using graft
copolymers in which short poly(ethylene oxide) chains are present
as pendant units attached to a long main chain. Such materials have
been described in GB-A-2161488. Another means of improving the
mechanical properties is to use block copolymers in which short
poly(ethylene oxide) chains alternate with other units such as
polysiloxane. Yet another means is to cross-link a poly(ethylene
oxide) with an epoxy compound. In each case the polymer electrolyte
contains a suitable salt complexed with the polymer to provide the
ionic species required for conductivity. In all these cases the
conductivities reported at 25.degree. C. or at room temperature are
at best about 10.sup.-4 Siemens per cm. These values are an order
of magnitude less than a commonly cited target for commercial
realization of 10.sup.-3 Siemens per cm.
It is also possible to provide polymer electrolytes which consist
of a mixture of a polymer, preferably of high molecular weight,
with a compound of low molecular weight that is a solvent for the
polymer in the range of temperatures in which the electrolyte is to
be sued, together with an appropriate salt that is soluble in the
polymer and in the compound of low molecular weight. For example,
as disclosed in GB-A-2212504 and 2216132, polymer electrolytes
consisting of poly-N,N-dimethylacrylamide or closely related
poly-N-substituted acrylamide of high molecular weight plasticized
with dimethylacetamide together with lithium trifluoromethane
sulphonate (lithium triflate) as the salt component have been
evaluated and found to exhibit good conductivities together with
good mechanical properties. These polymer electrolytes are gel-like
in character, but the compound of low molecular weight must not
exceed a certain limiting concentration above which the system
loses its gel-like character and begins to flow. The ionic
conductivity is higher at the higher concentrations of the compound
of low molecular weight, but the material becomes increasingly more
flexible. Conductivities of 7.times.10.sup.-3 Scm.sup.-1 at
20.degree. C. are obtainable but this requires at least 60% or more
of the low molecular weight compound and at this level the
mechanical properties are poor. It has proved possible by
cross-linking the polymer to improve the mechanical properties to a
useful level with as much as 80% of the low molecular weight
compound present, and thus to obtain conductivities at 20.degree.
C. exceeding 10.sup.-3 Scm.sup.-1. These products may prove of
commercial interest, but the process for making the cross-linked
polymer electrolyte film is somewhat complex for convenient
incorporation into a process for cell manufacture.
DESCRIPTION OF THE INVENTION
This invention seeks to provide ionically conductive materials that
provide high bulk tonic conductivities at ambient temperature
together with good mechanical properties.
According to one aspect of the invention there is provided an
ionically conductive, ion-containing gel having a bulk ionic
conductivity at 20.degree. and 10 kHz greater than 10.sup.-4
Siemens per centimetre and a dynamic modulus at 10 Hz greater than
10.sup.3 Pa. preferably greater than 10.sup.4 Pa, e.g. >10.sup.5
Pa, wherein the gel consists of a minor amount of a crystallizable
polymer such as a polyester, a major amount of an organic compound
that is a solvent for a salt at 20.degree. C. but is not a solvent
for the crystallizable polymer at 20.degree. C., and a salt
dissolved in the organic compound at a concentration greater than
4% by mass based on the organic compound. The said minor amount is
up to 50% by mass, preferably up to 40%, e.g. at least 5% such as
at least 10%, typically 20-30%.
The ion-containing gels of this invention can provide better ionic
conductivities both an ambient and elevated temperatures than
polymer electrolytes based on polymer-salt complexes previously
described and better mechanical properties than polymer
electrolytes of good ionic conductivity based on
polymer-salt-plasticizing solvent complexes previously
described.
The ion-containing gels of this invention can normally be regarded
as thermoreversible gels in which the junctions are physical
associations, possibly corresponding with crystal structures
comprising only a small portion of the polymer chains.
The crystallizable polymer may itself be capable of complexing with
the salt through containing, for example, ether or amide groups,
but it is not essential that the crystallizable polymer should
dissolve or complex with the salt. This contrasts with previously
described ion-conducting electrolyte systems based upon polymers
where it has been essential that the polymer should dissolve or
complex the salt and desirable that the polymer should be
non-crystallizable.
Suitable crystallizable polymers for use in this invention include
crystallizable polyesters such as poly(ethylene terephthalate),
poly(1,4-butylene terephthalate) and poly(3-oxybutanoate),
crystallizable polyamides such as poly (hexamethylene adipamide)
and poly(m-phenylene isophthalamide), crystallizable polyethers and
crystallizable substituted (e.g. halo) polyolefins such as
substituted polyvinylidenes. Further examples include
polyhydroxybutyric acid, poly(metaxylylene adipamide),
poly(vinylidene fluoride), polyoxymethylene and polyoxyethylene.
The crystallizable polymer is normally dissolved at a high
temperature in the other components and can provide the required
mechanical rigidity for the product at lower temperatures. If
inadequate crystallizable polymer is present, the mechanical
properties and dimensional stability will suffer. The
crystallizable polymer is preferably of a sufficiently high
molecular weight to form coherent films and fibres. In general, the
higher the molecular weight of the polymer, the better the
mechanical properties of the gel structure formed and the lower the
concentrate of the polymer required to maintain a gel structure,
and the lower the concentration of polymer, the higher the
conductivity.
Suitable organic compounds that are solvents for a salt at
20.degree. C. but are not solvents for the crystallizable polymer
at 20.degree. C. include amides (preferably tertiary amides) which
may be cyclic such as dimethyl formamide, dimethyl acetamide,
N-methyl-2-pyrrolidinone and N-formyl piperidine, sulphoxides and
ethers (preferably polyfunctional) such as the dimethyl ethers of
diethylene glycol, triethylene glycol and tetraethylene glycol.
Mixtures of such compounds may also be used. Where its more modest
oxidation-reduction stability is adequate, the solvent organic
compound may be dimethyl sulphoxide. It will be understood that
these compounds do become solvents for the crystallisable polymer
at some temperature above 20.degree. C., e.g. above 100.degree. C.
or above 150.degree. C. For use in batteries it is preferable that
the organic compounds should be free from chemical groups that can
react with electrode components. Thus for lithium batteries the
organic compounds should not contain hydroxyl groups and should be
as free of water as possible.
Suitable salts include alkali metal salts such as salts of lithium,
sodium or potassium and substituted or unsubstituted ammonium.
Lithium is particularly preferred because of the high solubility of
many lithium salts in suitable organic compounds and the importance
of lithium as an electrode material. The counterbalancing anion is
preferably large and preferably a weak conjugate base. Examples
include the monovalent anions derived from higher halogens and
pseudohalogens, for example Br.sup.-, I.sup.- and SCN.sup.- and
complex inorganic, carboxylic and sulphonic, preferably
perfluorinated alkyl carboxylic and sulphonic, monovalent anions,
for example ClO.sub.4.sup.-, HgI.sub.3.sup.-, BF.sub.4.sup.-,
CF.sub.3 COO.sup.-, and CF.sub.3 SO.sub.3.sup.-. The concentration
of salt based in the organic compound should be greater than 4% by
weight and is limited at the upper end of the range by a saturation
solubility of the salt in the organic compound in the presence of
the polymer. The salt Is preferably present in the gel structure at
a concentration such that it does not exceed its saturation
solubility throughout the proposed temperature range of use. Hence,
for each combination of organic compound and salt and intended
temperature there is an optimum concentration of salt for the
highest conductivities to be obtained.
Gels according to this invention may be prepared by forming a
solution of the polymer in the organic compound at above 20.degree.
C. (preferably above 100.degree. C. such as above 150.degree. C.),
incorporating the salt into the solution either by addition after
it has been formed or simultaneously or preferably by solution in
the organic compound before the addition of the polymer, then
cooling the solution. Such cooling will be understood to be to a
temperature below the critical solution temperature of the polymer
in the mixture of the organic compound and the salt.
The present invention also provides a galvanic cell wherein the
electrolyte comprises an ionically conductive gel as herein
defined; and a battery of such cells.
BRIEF DESCRIPTION OF THE DRAWING
The invention will now be described with reference to the
accompanying drawing, in which:
FIG. 1 shows the results of a series of conductivity measurements
carried out over a range of temperatures.
EXAMPLES
The following Examples illustrate the invention.
Test Methods
Cell Preparation and Measurement of Ionic Conductivity
Gel samples were re-heated until they melted and then cast on to a
stainless steel (ion-blocking) electrode. A second stainless steel
electrode was rapidly brought into contact with the gel so that the
gel was sandwiched between the electrodes and good contact with
both electrodes was achieved. The contact area A and electrolyte
thickness t were accurately known; in all cases A was 1.0 cm.sup.2
and t was in the range 0.86-1.69 mm.
The prepared cell was then immediately transferred to the chamber
in which the conductivity measurements were carried out, which was
flooded with dry nitrogen to present exposure of the cell to the
atmosphere. Brass plates were used to provide electrical contact
with both electrodes. The temperature of the sample was controlled
by passing the dry nitrogen over a heat exchanger before it entered
the chamber; a thermocouple positioned near to the cell was used to
monitor the temperature, which was controlled by a Euro-therm
temperature control unit.
A Solartron 1250 frequency response analyser and latterly a
Schlumberger 1260 impedance/gain-phase analyser were used to
measure the complex admittance of the celt in the frequency range
0.1 Hz to 63 kHz. Due to the blocking nature of the electrodes, the
real part of the admittance rose with frequency to a plateau. The
bulk gel electrolyte resistance R.sub.b was calculated from the
frequency-independent plateau observed in the real part of the
admittance at frequencies above around 10 kHz. The ionic
conductivity .delta. was then calculated from the expression
##EQU1##
Measurement of Gel Modulus
Gel electrolytes were cast Into discs of diameter 25 mm and
thickness approximately 2 mm (.+-.0.3 mm). These discs were placed
between parallel circular disc platens of 25 mm diameter in a
Rheometrics Dynamic Spectrometer RDS2, at ambient temperature
(18.degree. C. to 23.degree. C.) in a nitrogen atmosphere, and
squeezed under an axial load up to 1 kg to the measurement
thickness H.
Two mechanical measurements were made:
1) Dynamic Modulus G.sup.1
One of the disc platens oscillates sinusoidally about its
cylindrical axis of symmetry with an applied shear strain
amplitude. Shear strain is measured at the circumference, or
maximum radius R, using the maximum sine wave (zero to peak)
angular displacement .theta., such that ##EQU2##
The in-phase component of the measured sinusoidal shear stress is
used to determine the dynamic modulus G.sup.1. First, therefore,
stress is obtained from the torque or couple measured at the
opposite platen using the formula: ##EQU3##
(with torque in gram centimeters). Then ##EQU4##
where .delta. is the phase lag between the stress and strain sine
waves.
G.sup.1 was measured for frequencies between 0.016 Hz and 79.6 Hz.
Values of G.sup.1 may increase slightly with frequency and are
quoted for 1% shear strain and 10 Hz frequency.
2) Relaxation Modulus G(t)
Using the same geometry, a step shear strain of 1% is applied. The
stress then decays from its maximum as a function of time.
##EQU5##
where .phi. is a fixed angular displacement.
The relaxation modulus is then given by ##EQU6##
where stress is the same as above.
The modulus G(t) is stated for 1% strain after a relaxation time of
100 seconds.
Example 1--PET-NMP
N-Methyl-2-pyrrolidinone (NMP) was dried over a molecular sieve.
Lithium trifluoromethanesulphonate CF.sub.3 SO.sub.3 Li (lithium
triflate) was dried over phosphorous pentoxide for 48 h.
Poly(ethylene terephthalate)(PET) chips, of intrinsic viscosity
0.96 dl/g (1% in dichloroacetic acid at 25.degree. C.) were dried
at 120.degree. C. for 4 h under reduced pressure.
To 9.0 g of molecular-sieve-dried N-methyl-2-pyrrolidinone were
added 1.0 g of dried poly(ethylene terephthalate) chips and 1.18 g
dried lithium triflate, all in a dried glass sample tube. The tube
was sealed and transferred to a silicone oil bath at 200.degree. C.
The contents were stirred intermittently and heated until the chips
dissolved completely, which occurred at a bath temperature of about
215.degree. C. The solution was then allowed to cool to room
temperature. During cooling, the solution ceased to flow and
solidified to a gel.
The gel was reheated until it flowed and was then cast under dry
conditions in liquid form on to one of the electrodes of the
frequency response analyser system. It was sandwiched between the
two electrodes and allowed to cool in situ to re-form the gel
structure which was a flexible film with good recovery from
deformation.
A series of conductivity measurements was carried out over a range
of temperatures, and the results are shown graphically in FIG. 1.
The conductivity at 25.degree. C. was found to be 10.sup.-3.2
Siemens per centimetre.
Example 2--PET-1FP
Example 1 was repeated using 1-formylpiperidine (1FP) instead of
N-methyl-2-pyrrolidinone and 1.03 g of lithium triflate instead of
1.18 g. The conductivities over a range of temperature are shown
graphically in FIG. 1. The conductivity at 25.degree. C. was found
to be 10.sup.-3.5 Siemens per centimetre.
Dynamic mechanical measurements were performed on several shaped
samples prepared according to Examples 1 and 2 using both parallel
plates and cone-and-plate sample holders. The samples were subject
to an alternating shear strain and the resulting shear stress
measured and correlated against the input strain. The measured
shear module were generally independent of frequency over the range
0.1 to 500 rad/s and the shear relaxation modulus was determined to
be about 10.sup.3 Pa. The dynamic modulus of all these samples was
found to exceed 10.sup.3 Pa at 10 Hz.
The accompanying drawing shows the results from these two Examples
on a log-conductivity/inverse temperature plot.
Examples 3-11
The general procedure adopted was as follows:
Dry lithium triflate was dissolved in the dry solvent at room
temperature in a sealed dry flask using the molar proportion
required of lithium triflate to solvent. A measured volume of the
solution was added to a measured weight of the polymer in a dry
vessel and the mixture was heated, with mechanical stirring, by
means of an oil bath pre-set at a temperature above 150.degree. C.
sufficient to cause the polymer to dissolve. The vessel was sealed
and quenched to room temperature to cause gel formation.
The conductivity and modulus measurements were made using the
procedures already described.
The polymers used for these Examples (and for Examples 1 and 2)
were obtained as follows:
Poly(ethylene terephthalate) (PET) was a bottle-grade polymer of
[.eta.] 0.96, in pellet form.
Poly(vinylidene fluoride) (PVDF) was obtained from Polysciences
Inc. in pellet form. It had a weight average molecular weight,
according to the suppliers, of 100,000.
Polyhydroxybutyric acid (PHBA) was obtained from Aldrich in powder
form. It had a weight average molecular weight, according to the
suppliers, of 670,000.
Poly(metaxylylene adipamide) (MXD,6) was Mitsubishi Grade 6001.
Nylon 6,6 was obtained from ICI in the form of granules, Type
R6600.
Polyoxymethylene was obtained from Aldrich in the form of
beads.
Results of the conductivity and modulus measurements for Examples
3-11 are given in Table 1. In this Table the abbreviations are as
follows:
DMF dimethyl formamide
DMSO dimethyl sulphoxide
TGDME tetraethylene glycol dimethyl ether
NMP N-methyl pyrrolidinone
DMA dimethyl acetamide
The values of G.sub.1 are measured at 1% strain amplitude and a
frequency of 10 Hz. The values of G(t) are measured 2 minutes after
application of a strain of 1%. Both G.sup.1 and G(t) are measured
at ambient temperature.
TABLE 1 Mass Polymer % Li conc. Conductivity triflate wt % of at
Dynamic Relaxation based total 20.degree. C. modulus modulus
Example Polymer Solvent on solvent gel S cm.sup.-1 G.sup.1 (Pa)
G(t)Pa) 3 PVDF DMF 16.8 26.5 6.6 .times. 10.sup.-3 3 .times.
10.sup.5 2 .times. 10.sup.5 4 PVDF DMSO 18.3 23.8 4.6 .times.
10.sup.-3 2 .times. 10.sup.5 1 .times. 10.sup.5 5 PVDF TGDME 5.9
27.2 2.0 .times. 10.sup.-4 1 .times. 10.sup.5 7 .times. 10.sup.4 6
PET NMP 13.5 27.2 2.0 .times. 10.sup.-3 2 .times. 10.sup.5 1
.times. 10.sup.5 7 PHBA DMA 14.0 13.4 3.6 .times. 10.sup.-3 3
.times. 10.sup.5 -- 8 PHBA DMA 14.0 21.8 1.5 .times. 10.sup.-3 1
.times. 10.sup.5 7 .times. 10.sup.4 9 MXD,6 NMP 13.5 12.6 2.4
.times. 10.sup.-3 2 .times. 10.sup.5 1 .times. 10.sup.5 10 Nylon
6,6 NMP 13.5 7.9 2.2 .times. 10.sup.-3 4 .times. 10.sup.4 -- 11 POM
NMP 13.5 20.5 2.9 .times. 10.sup.-4 5 .times. 10.sup.4 3 .times.
10.sup.4
* * * * *