Solid Polymer Electrolytes with Excellent High-Temperature Properties

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Solid Polymer Electrolytes with Excellent High-Temperature Properties Based on Brush Block Copolymers Having Rigid Side Chains Jing Ping, Hongbing Pan, Ping-Ping Hou, Meng-Yao Zhang, Xing Wang, Chao Wang, Jitao Chen, Decheng Wu, Zhihao Shen, and Xing-He Fan ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.6b15893 • Publication Date (Web): 27 Jan 2017 Downloaded from http://pubs.acs.org on January 28, 2017

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ACS Applied Materials & Interfaces

Solid Polymer Electrolytes with Excellent High-Temperature Properties Based on Brush Block Copolymers Having Rigid Side Chains

Jing Ping,a Hongbing Pan,a Ping-Ping Hou,a Meng-Yao Zhang,a Xing Wang,b Chao Wang,a Jitao Chen,a Decheng Wu,b Zhihao Shen,a,* and Xing-He Fan a,* a

Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Center for Soft Matter Science and Engineering, and College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China b

Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China

* To whom correspondence should be addressed. E-mail: [email protected] (X.-H.F.); [email protected] (Z.S.)

Abstract: In this work, a series of brush block copolymers (BBCPs) with polynorbornene backbones containing poly{2,5-bis[(4-methoxyphenyl)-oxycarbonyl]styrene} (PMPCS, which is a rigid chain) and polyethylene oxide (PEO) side chains were synthesized by tandem ring-opening metathesis polymerizations. The weight fractions of PEO in BBCPs are similar and the degrees of polymerization (DPs) of PEO side chains are the same, while the DPs of PMPCS are different. The bulk self-assembling behaviors were studied by small-angle X-ray scattering (SAXS). The neat BBCPs can not form ordered nanostructures. However, after the doping of lithium salt, the BBCPs self-assemble into lamellar (LAM) structures. When the DPs of the PEO 1

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and PMPCS side chains are similar, the LAM structure is more ordered, which is attributed to the more flat interface between PMPCS and PEO phases. The ionic conductivity (σ) values of the BBCP/lithium salt complex with the most ordered LAM structure at different temperatures were measured. The σ value increases with increasing temperature in the range of 40−200 oC, and the relationship between σ and T fits the Vogel-Tamman-Fulcher (VTF) equation. The σ value at 200 oC is 1.58×10−3 S/cm, which is one of the highest values for PEO-based polymer electrolytes. These materials with high σ values at high temperatures may be used in high-temperature lithium ion batteries. Keywords: brush block copolymer, high temperature, ionic conductivity, rigid side chain, lamellar structure

Introduction The global energy consumption increases year by year, which will cause the energy gap problem.1,2 In addition, the use of fossil energy results in the climate warming, which affects our daily life. One way to solve the energy and environmental problems is to develop energy storage systems, such as lithium ion batteries.3-5 Because lithium ion batteries have many advantages, such as high energy density,6 large output power, high output voltage, and weak memory effect,7-9 they attract the interests of scientists. Now electrolytes in the market are liquid electrolytes, with some problems, such as evaporation, leakage,10 and safety concerns.11 In contrast, solid polymer electrolytes (SPEs) greatly improve the battery safety owing to their good thermal and mechanical stability.12 Furthermore, with lithium metal used in lithium ion batteries 2


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with SPEs,13-16 the energy density can be increased to 500 Wh/kg.17 Polyethylene oxide (PEO)/lithium salt complex can be used as an SPE.17-19 The lithium salt complexes with PEO homopolymers have high ionic conductivity. However, their mechanical strength is not satisfactory, which affects their application in lithium ion batteries.20,21 Block copolymers (BCPs) with PEO and lithium salt can improve the mechanical strength. Owing to the interaction of lithium ion with oxygen in the PEO chain, lithium salts are distributed among PEO chains and can transport lithium ions.22-24 So far the most common BCP used is poly(styrene-b-ethylene oxide) (PS-b-PEO). However, when the temperature is higher than the glass transition temperature (Tg, about 100 oC) of PS, the elastic modulus of the BCP/LiX complex will be below 103 Pa,25,26 which will cause safety problems. If lithium ion batteries are used in rockets, satellites, or fighters, they usually need to withstand high temperatures. Thus, it is necessary to find SPEs that can be used at high temperatures. One way to improve the service temperature of polymer electrolytes is to replace PS chains with rigid chains that have higher Tg values. Mesogen-jacketed liquid crystalline polymer (MJLCP) is a kind of rigid chain, which was proposed by Zhou et al. in 1987.27 MJLCPs have bulky side groups attached to the polymer backbones directly or with very short spacers,

and

they

can

form

supramolecular

liquid

crystalline

(LC)

phases.28,29

Poly{2,5-bis[(4-methoxyphenyl)-oxycarbonyl]styrene} (PMPCS) is a typical MJLCP with a Tg of about 115 oC. It can maintain a columnar nematic phase and good mechanical stability up to 300 oC.30 The second way to improve the service temperature of polymer electrolytes is to introduce the polymer brush architecture into PEO-containing BCPs.26 There are large repulsive 3



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forces between adjacent branches in the polymer brush, which makes the main chain more stretched. Thus, the polymer brush acts as a rigid cylindrical macromolecule. Furthermore, the polymer brush has a small number of entanglements, which benefits its self-assembling behavior.31-33 Polymer brushes with PMPCS and PEO side chains are expected to have a high Tg and good mechanical stability, with improved service temperature when used as polymer electrolytes. In our previous work, we synthesized amphiphilic alternating copolymer brushes (AACPBs) containing PMPCS and PEO side chains, and the AACPB/lithium salt complexes have relatively high ionic conductivity at high temperatures (σ = 1.79×10-4 S/cm at 240 oC).34 However, the σ value is not high, which is attributed to the low PEO content. It is difficult to prepare AACPBs with longer PEO or shorter PMPCS side chains to increase the PEO content. Grubbs et al. prepared ABA triblock brush block copolymers (BBCPs, A is PS, and B is PEO) with tandem ring-opening metathesis polymerization (ROMP), and the σ value of the BBCP/lithium salt complex at 105 oC is 1×10−3 S/cm.35 Our objective is to obtain BBCP/lithium salt complexes having PMPCS and PEO side chains that possess high σ values at high temperatures. In this work, the BBCPs based on a polynorbornene (PNb) backbone, namely gPEO-b-gPMPCS, were synthesized with tandem ROMP. The BBCP/lithium salt complexes form lamellar (LAM) structures that can transport lithium ions. When the degrees of polymerization (DPs) of PEO and PMPCS side chains are similar, the LAM structure of the complex is the most ordered. The σ value of the complex at 200 oC is 1.58×10−3 S/cm that is one of the highest values for PEO-based polymer electrolytes. 4


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The σ value is an order of magnitude higher than that of the AACPB/lithium salt complex in our previous study,34 which is mainly attributed to the higher content of PEO and more ordered microphase-separated LAM structure.

Experimental Materials and Characterization Dichloromethane (CH2Cl2) was purified with the Solvent Processing System (M.Braun, Inc.).

4-Dimethylaminopyridine

(DMAP),

1-ethyl-3-(3-dimethylaminopropyl)carbodiimide

hydrochloride (EDC.HCl), and N,N,N',N'',N''-pentamethyldiethylenetriamine (PMDETA) were purchased from J&K Scientific. All other reagents were used as received without purification. 1H NMR spectra, gel permeation chromatographic (GPC) and GPC coupled with multiangle laser light scattering (GPC-MALLS) measurements, thermogravimetric analysis (TGA) examinations, one-dimensional (1D) wide-angle X-ray diffraction (WAXD) experiments, and small-angle X-ray scattering (SAXS) experiments were carried out according to our previous work.34 Differential scanning calorimetry (DSC) was conducted on a TA DSC Q100 instrument on the first cooling and a subsequent heating process at a rate of 10 °C/min in a nitrogen atmosphere. Synchrotron radiation SAXS experiments were performed at Synchrotron X-ray Beamline 1W2A in Beijing Synchrotron Radiation Facility (BSRF)36 and Synchrotron X-ray Beamline BL16B1 in Shanghai Synchrotron Radiation Facility (SSRF). The wavelength of the X-ray beam in BSRF was 0.154 Å, while that in SSRF was 0.124 Å. The values of ionic conductivity σ at different temperatures were obtained by electrical impedance spectrum measurements in an Autolab 5



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electrochemistry workstation and thermal platform. The polymer electrolyte was sandwiched between two stainless steel disk electrodes of a button cell, and then the button cell was extruded.

Synthesis of BBCPs Scheme 1 shows the whole synthetic route. The Nb-PEO macromonomer was synthesized according to the literature,35 and the detailed process is described in the Supporting Information (Scheme S1). The Nb-PMPCS macromonomers were synthesized according to our previous work.37

The

BBCPs

were

synthesized

with

tandem

ROMP.

The

synthesis

of

gPEO24-b-gPMPCS23 (the numbers represent the DPs of the side chains) is described below as an example. Grubbs III catalyst (1 eq, 11.8 mg, 0.0133 mmol) was charged into a flask with a stir bar, and then the flask was degassed with three pump-purge cycles with high purity nitrogen. CH2Cl2 (~0.7 mL) was injected into the flask to dissolve the catalyst, and a solution of Nb-PEO (30 eq, 539 mg, 0.400 mmol) in 2 mL of CH2Cl2 was added into the mixture. After the mixture was stirred at 25 °C for 30 min, trace samples were taken out from the mixture to perform GPC examination, and then a solution of Nb-PMPCS 2 (6 eq, 776 mg, 0.0800 mmol) in 6.2 mL of CH2Cl2 was injected into the flask quickly. Following polymerization at 25 °C for 6 h again, the solution was passed through a neutral alumina column to remove the Grubbs III catalyst and the unreacted macromonomers, and then it was precipitated into 200 mL of petroleum ether to obtain a white solid. Scheme 1. Synthesis of BBCPs

6


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n n p

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Doping of Lithium Salt The polymer brush (20.0 mg) and an appropriate amount of bistrifluoromethanesulfonimide lithium (LiN(CF3SO2)2, namely LiTFSI) were dissolved in 1.5 mL of tetrahydrofuran (THF), and the mixture solution was stirred at ambient temperature for 24 h. After the solution was passed through a filter membrane with a diameter of 0.22 µm, the solvent was evaporated at ambient conditions. The residual solid was annealed in vacuum at 150 °C for 36 h. The salt concentration was calculated based on the molar ratio of LiTFSI to ethylene oxide (EO) that was defined as the doping ratio r = [Li+]/[EO].

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Results and Discussion Synthesis of BBCPs The DP and molecular weight (MW) of Nb-PEO are 24 and 1347, respectively. Three Nb-PMPCS samples with different MWs were obtained by controlling the feeding ratio and the polymerization time. Table 1 summarizes the polymerization conditions and properties of Nb-PMPCS macromonomers, and Figure 1a shows the GPC traces of the Nb-PEO and Nb-PMPCS macromonomers.

Table 1. Polymerization Conditions and Properties of Nb-PMPCS Macromonomers Entry

[M]0/[I]0

Time

Mn a

ĐM a

(h)

(103 g/mol)

Mn b

DP c

(103 g/mol)

Td d

Tg e

(°C)

(°C)

Nb-PMPCS 1

30

3

4.0

1.08

6.1

14

361

117

Nb-PMPCS 2

40

4

6.4

1.10

9.7

23

373

123

Nb-PMPCS 3

70

6

10.8

1.09

16.4

40

382

117

a

Determined by GPC in THF (calibrated with PS standards).

b

Absolute MW calculated by Mna×1.52 according to our previous report.38

c

The ratio of the absolute MW of Nb-PMPCS to the MW of MPCS.

d

5% weight loss temperature (Td) was determined by TGA at a heating rate of 10 °C/min under

nitrogen. e

Tg was obtained from the DSC thermogram during the second heating process at a rate of

8


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10 °C/min under nitrogen.

Figure 1. GPC traces of different macromonomers (a), gPEO24-b-gPMPCS23 and its macromonomers (b), and other BBCPs and their macromonomers (c).

The target BBCP gPEO24-b-gPMPCS23 is pure, as proven by the GPC trace (Figure 1b). Figure 2 shows the 1H NMR spectrum of gPEO24-b-gPMPCS23, and all characteristic resonance peaks correspond to hydrogens in PEO and PMPCS. By comparing the areal integrals of peak a, b, and i, and that of h, we deduce that the ratio of PEO side chains to PMPCS side chains in the BBCP is 4:1. The GPC traces of gPEO24-b-gPMPCS14 and gPEO24-b-gPMPCS40 are shown in Figure 1c. GPC-MALLS measurements were performed to determine the absolute MWs of the BBCPs. Combining the ratio of PEO to PMPCS chains, the MWs of Nb-PEO and Nb-PMPCS side chains, and the absolute MW of the BBCP, the PEO content and the DP of the main chain can be calculated. The molecular characteristics of the BBCPs are summarized in Table 2, and the PEO contents are all about 35.0 wt%, which is higher than that of AACPB containing PMPCS and PEO side chains.34 9



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Figure 2. 1H NMR spectra of Nb-PEO in CDCl3 (bottom), Nb-PMPCS 2 in CDCl3 (middle), and gPEO24-b-gPMPCS23 in CD2Cl2 (top).

Table 2. Polymerization Conditions and Molecular Characteristics of the BBCPs Entry

DPNb-P a MPCS

b

[M]PEO/

[M]PMPCS

Mn, BBCP

[I]

/[I]

(10 g/mol)

PDI

b

DPmain

φPEO

b

3

chain

(wt%)

fPEO c

(%)

d

Td e (°C)

gPEO24-b-gPMPCS14

14

30

8

283.5

1.20

108

37.3

41.1

358

gPEO24-b-gPMPCS23

23

30

6

222.7

1.01

74

35.7

39.5

364

gPEO24-b-gPMPCS40

40

30

4

273.2

1.02

78

33.0

36.6

367

a

Obtained from Table 1.

b

Determined by GPC-MALLS (with THF as the eluent). 10


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c

Determined by 1H NMR.

d

Volume fraction of PEO, calculated on the basis of ρPMPCS = 1.28 g/cm3, ρPEO = 1.09 g/cm3, and

the mass fraction of PEO. e

Determined by TGA at a heating rate of 10 °C/min under nitrogen.

Thermal Properties of BBCPs The thermal stabilities of the BBCPs were studied by TGA, and all samples exhibit excellent thermal stabilities with the 5% weight loss temperatures (Td’s) above 350 °C (Table 2). DSC was used to investigate the phase behaviors, with thermograms of Nb-PEO, Nb-PMPCS 2, gPEO24-b-gPMPCS23, and gPEO24-b-gPMPCS23/LiTFSI (r = 0.6) as an example (Figure 3). Nb-PEO shows a glass transition at -50 oC, a cold crystallization peak at -27 oC, and a board melting peak at ~20 oC, while Nb-PMPCS 2 exhibits a glass transition at 122 oC. However, it is difficult to recognize any thermal transitions form the curve of gPEO24-b-gPMPCS23, suggesting that the sample is disordered and that the crystallization of the PEO side chains is suppressed. Interestingly, the DSC curve of gPEO24-b-gPMPCS23/LiTFSI (r = 0.6) exhibits a glass transition of PEO at -43 oC and a weak glass transition of PMPCS at 112 oC, indicating that gPEO24-b-gPMPCS23/LiTFSI (r = 0.6) is microphase-separated. Comparison of the DSC results of gPEO24-b-gPMPCS23 and gPEO24-b-gPMPCS23/LiTFSI (r = 0.6) indicates that the addition of lithium salt induces the BBCP to microphase separate into PEO (with lithium salt) and PMPCS phases.

11



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Figure 3. Second-heating DSC thermograms of Nb-PEO, Nb-PMPCS 2, gPEO24-b-gPMPCS23, and gPEO24-b-gPMPCS23/LiTFSI (r = 0.6) at a rate of 10 °C/min following a cooling process at 10 °C/min.

LC Properties of BBCPs The LC behaviors of the BBCPs were studied by variable-temperature 1D WAXD experiments. The 1D WAXD profiles of Nb-PMPCS 2 (Figure 4a) only have two broad halos in the low- and high-angle regions during the heating process, which indicates that this PMPCS sample is amorphous. Note that the broad halo at 2θ = 6.67o in all 1D WAXD profiles is from background. The 1D WAXD profiles of Nb-PMPCS 1 (Figure S2a in the Supporting Information) and gPEO24-b-gPMPCS14 (Figure S2b) are similar to those of Nb-PMPCS 2, demonstrating the amorphous nature of the PMPCS chains. However, in the 1D WAXD profiles of gPEO24-b-gPMPCS23 (Figure 4b), the original scattering halo at 2θ = 5.14o in the low-angle region, which comes from the lateral packing of the PMPCS side chains, becomes a diffraction peak with a 2θ value of 5.55o at 180 oC, with the peak intensity increasing during heating. Because the 1D WAXD results of gPEO24-b-gPMPCS23 are similar to those of linear PMPCS 12


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that forms a columnar nematic (Coln) LC phase according to our previous report,30 the PMPCS side chains in the BBCPs also develop into a Coln phase when the temperature is above 180 oC. The difference between the LC behavior of Nb-PMPCS 2 and that of gPEO24-b-gPMPCS23 illustrates that the BBCP architecture also improves liquid crystallinity as AACPB.34 In addition, the diffraction peak at 2θ = 5.55o in the 1D WAXD profiles of gPEO24-b-gPMPCS23 becomes a broad halo when the temperature is below 160 oC during cooling, indicating the PMPCS chains in the BBCP become amorphous again. The 1D WAXD profiles of Nb-PMPCS 3 (Figure S2c in the Supporting Information) and gPEO24-b-gPMPCS40 (Figure S2d) are similar to those of gPEO24-b-gPMPCS23, demonstrating that both samples form Coln phases.

Figure 4. 1D WAXD profiles of Nb-PMPCS 2 (a) and gPEO24-b-gPMPCS23 (b) at different temperatures.

13



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Lithium Salt-Induced Microphase Separation of BBCPs SAXS was used to investigate the self-assembling behaviors of the neat and lithium salt-doped BBCPs. The measurements were performed after the samples were treated by solvent annealing with THF and thermal annealing at 150 oC for 24 h. The SAXS profiles of gPEO24-b-gPMPCS14 are shown in Figure 5a, and there is no diffraction peak in the low-angle region, indicating that the BBCP is disordered. However, after the doping of 0.1–0.8 eq LiTFSI, the SAXS profiles of the gPEO24-b-gPMPCS14/LiTFSI complexes (Figure 5a) all exhibit two diffraction peaks with a scattering vector ratio of 1:2, demonstrating that these complexes all form LAM nanostructures. The position of the first-order diffraction peak shifts from 0.170 nm-1 to 0.165 nm-1 (with the d-spacing changing from 36.9 nm to 38.1 nm) when the doping ratio is increased from 0.1 to 0.8, which is mainly due to the larger volume of the PEO/lithium salt phase with increasing amount of lithium salt. Although the Coln LC phases formed by the PMPCS chains in gPEO24-b-gPMPCS23 and gPEO24-b-gPMPCS40 at high temperatures can provide an additional free energy of mixing, resulting in a larger value of the Flory-Huggins interaction parameter χ,39 such an increase in χ is not large enough for the BBCPs to form ordered self-assembling nanostructures (parts b and c of Figure 5). The SAXS profiles of gPEO24-b-gPMPCS23/LiTFSI (r = 0.2–0.8) (Figure 5b) all show two or three low-angle diffraction peaks with a scattering vector ratio of 1:3, 1:2:3, or 1:2, indicating that these samples also microphase separate into LAM structures having a d-spacing value of ca. 37.8 nm. There are also three diffraction peaks with a scattering vector ratio of 1:2:3 in the SAXS profiles of gPEO24-b-gPMPCS40/LiTFSI (r = 0.6–0.8) (Figure 5c), indicative of LAM nanostructures. It is 14


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worth noting that the SAXS profile of gPEO24-b-gPMPCS23/LiTFSI (r = 0.6) exhibits three sharp diffraction peaks with a q ratio of 1:2:3, demonstrating that the LAM nanostructure formed by this complex is the most ordered one. The self-assembling behaviors of the BBCPs and their complexes are illustrated in Figure 6. For gPEO24-b-gPMPCS23/LiTFSI (r = 0.6), because the DPs of the PEO and PMPCS side chains are similar, the interface may be more or less flat, leading to a more ordered LAM structure.

Figure 5. SAXS profiles of gPEO24-b-gPMPCS14/LiTFSI (a), gPEO24-b-gPMPCS23/LiTFSI (b), 15



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and gPEO24-b-gPMPCS40/LiTFSI (c) with different doping ratios at ambient temperature.

Figure 6. Schematic illustration of the LiTFSI-induced microphase separation of the BBCP.

Ionic Conductivity and SAXS Profiles of Lithium Salt-Doped BBCPs at Different Temperatures Electrical impedance spectrum measurements were used to investigate the composition and temperature dependencies of the ion conductivities of lithium salt-doped BBCPs. Figure 7a illustrates the σ values of gPEO24-b-gPMPCS23/LiTFSI, gPEO24-b-gPMPCS14/LiTFSI (r = 0.6), and gPEO24-b-gPMPCS40/LiTFSI (r = 0.6) at ambient temperature. The σ values of gPEO24-b-gPMPCS23/LiTFSI (r = 0.6) is higher than those of the other complexes. Because the SAXS results in the previous section indicates that the LAM nanostructure formed by gPEO24-b-gPMPCS23/LiTFSI (r = 0.6) is the most ordered, we deduce that the more ordered LAM structure leads to a higher σ value.

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Figure 7. σ values of different lithium salt-doped BBCPs at ambient temperature (a), SAXS profiles of gPEO24-b-gPMPCS23/LiTFSI (r = 0.6) at different temperatures (b), and the plot of the logarithmic scale of σ of the complex vs 1/(T - T0) (c).

Because the σ value of gPEO24-b-gPMPCS23/LiTFSI (r = 0.6) at ambient temperature is the highest, we chose this complex to study the temperature dependence of the self-assembling behavior and the ionic conductivity. The SAXS profiles of gPEO24-b-gPMPCS23/LiTFSI (r = 0.6) 17



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(Figure 7b) all exhibit three diffraction peaks with a q ratio of 1:2:3 during heating, demonstrating that the complex maintains the LAM structure from ambient temperature to 240 o

C, which can be attributed to the rigid PMPCS side chain, the stable LC phase, and the brush

architecture. Furthermore, the position of the first-order diffraction peak slightly shifts from 0.144 nm-1 to 0.138 nm-1 (with the d-spacing increasing from 43.6 nm to 45.5 nm) during heating, which is consistent with the general trend of thermal expansion at higher temperatures. The σ value of the complex (Figure 7c) increases with increasing temperature between 30 oC and 200 o

C, which is in accord with the general rule that ionic mobilities are higher at higher

temperatures. In addition, the σ value and temperature fit the Vogel-Tamman-Fulcher (VTF) equation. The relationship of the logarithmic scale of σ and 1/(T - T0) is also linear at high temperatures (up to 200 oC), which benefits from the stable LAM structure at high temperatures. The σ value at 200 oC is 1.58×10-3 S/cm, which is one of the highest values for PEO-based polymer electrolytes. Therefore, the BBCP/LiTFSI complexes are likely to be used as polymer electrolytes in high-temperature lithium ion batteries. Compared with lithium salt-doped AACPB, the higher σ value of the lithium salt-doped BBCP is attributed to the higher PEO content and the more ordered LAM structure.

Conclusions A series of gPEO-b-gPMPCS BBCPs were synthesized through the tandem ROMP, and their complexes with LiTFSI self-assemble into LAM nanostructures. When the length of the PMPCS side chain is the same as that of PEO, the complex gPEO24-b-gPMPCS23/LiTFSI (r = 18


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0.6) forms the most ordered LAM structure, resulting in a higher ionic conductivity at ambient temperature than those of other samples. The microphase-separated nanostructure of gPEO24-b-gPMPCS23/LiTFSI (r = 0.6) remains LAM from ambient temperature to 240 oC, which benefits from the rigid PMPCS side chains, the stable Coln phase, and the brush architecture. The

σ value of the complex at 200 oC is 1.58×10-3 S/cm, which means that the σ value reaches the top level for PEO-based polymer electrolytes. This BBCP/LiTFSI complex is potentially useful as SPEs in lithium ion batteries operating at high temperatures.

■ ASSOCIATED CONTENT Supporting Information The Supporting Information is available free of charge on the ACS Publications website at http://pubs.acs.org: Synthesis of Nb-PEO, 1H NMR spectrum of Nb-PEO, and 1D WAXD profiles of brush block copolymers (PDF) ■ AUTHOR INFORMATION Corresponding Author *[email protected] (X.-H.F.); [email protected] (Z.S.) Notes The authors declare no competing financial interest.

■ Acknowledgements This work is supported by National Natural Science Foundation of China (Grants 21374002, 21574001, 21134001 and 51473005). The authors gratefully acknowledge Synchrotron X-ray 19



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Page 20 of 27

Beamline 1W2A in Beijing Synchrotron Radiation Facility (BSRF) and Synchrotron X-ray Beamline BL16B1 in Shanghai Synchrotron Radiation Facility (SSRF) for the assistance with the SAXS experiments.

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"TOC graphic" only

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Solid Polymer Electrolytes with Excellent High-Temperature Properties

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