Ionic Liquid Incorporated Metal Organic Framework for High Ionic

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Ionic liquid incorporated metal organic framework for high ionic conductivity over extended temperature range Qiuxia Xu, Xiangping Zhang, Shaojuan Zeng, Lu Bai, and Suojiang Zhang ACS Sustainable Chem. Eng., Just Accepted Manuscript • DOI: 10.1021/ acssuschemeng.9b00543 • Publication Date (Web): 15 Mar 2019 Downloaded from http://pubs.acs.org on March 17, 2019

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ACS Sustainable Chemistry & Engineering

Ionic liquid incorporated metal organic framework for high ionic conductivity over extended temperature range Qiuxia Xu 1,2, Xiangping Zhang2, Shaojuan Zeng2, Lu Bai2, Suojiang Zhang2,* 1School 2Beijing

of Chemical Engineering and Technology，Tianjin University，Tianjin 300072，China； Key Laboratory of Ionic Liquids Clean Process, CAS Key Laboratory of Green Process and Engineering, State Key

Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China

Corresponding authors *Suojiang Zhang.Tel./fax: +86 10 82544875.E-mail addresses: [email protected] No. 1 Zhongguancunbeierjie road, Haidian District, Beijing, P.R.China 100190 ABSTRACT The combination of ionic liquids (ILs) and metal organic frameworks (MOF) as a new type hybrid ionic conductor has raised extensive concern. Novel solid electrolytes with high ionic conductivities and good cycle performance have been successfully synthesized by loading ILs into nanoarchitectures of MOF materials. In this work, two highly conductive ILs, 1-ethyl-3-methylimidazolium thiocyanate ([Emim][SCN]) and 1-ethyl-3-methylimidazolium dicyanamide ([Emim][DCA]), were embedded into the pores of MIL-101 by an effective soaking-volatilizing method. Using this method, a series of IL@MIL-101 composites with different IL contents were obtained. The effects of IL amount on pore volume, stability, morphology and conductivity were investigated. The results showed that the conductivity of the composites improved with increasing the amount of ILs. When the pores of MIL-101 material 1

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are fully filled with [Emim][SCN], the ionic conductivity of the composites can reach up to 6.21×10˗3 S·cm˗1 at 150 ℃ under N2 atmosphere, which is higher than traditional solid electrolytes. And the activation energy of this sample is estimated to be 0.18 eV, which is as low as other IL@MOF conductive composites. It is noteworthy that the IL@MOF hybrid composites can be regarded as a promising ionic-conductor due to the value of high conductivity and low activation energy. KEYWORDS: ionic liquid, solid electrolyte, ionic conductivity, high conductivity

Introduction In order to meet the increasing energy demand, developing new energy storage materials and technologies for sustainable development of society is imperative1-2. Among various advanced energy storage technologies, electrical energy storage technology is considered to be a very promising option3-4 due to their high energy density, and low pollution emission. For most kinds of electrical energy storage devices, such as supercapacitors, secondary batteries and so on5-7, one key component were the electrolytes. Traditionally, organic solvents have been widely used in producing electrolyte. However, the safety risk of organic solvents has restricted their development because of the high flammability, poor thermal stability, low heat capacity and potential corrosion after leakage8-11. In order to avoid the disadvantages of organic solvents, researchers successfully developed the solid-state electrolytes, which can discard the weakness of organic solvent. But unfortunately, its low conductivity at room temperature (10˗5 - 10˗7 S·cm˗1) could be hard to meet the practical application requirements (>10˗3 S·cm˗1), and limited 2


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its development in electrical energy storage area. Therefore, the development of new electrolytes is worth consideration. Ionic liquids (ILs) are one of the promising candidate materials for excellent electrolytes in electrical energy storage devices12-18. As a new type of green solvent, ILs have many remarkable properties, such as negligible volatility, non-flammability, high thermal and electrochemical stability, and high ionic conductivity19. However, the fluidity of ILs can also cause leakage and subsequent corrosion of equipment, just like the organic solvents. On the other hand, Metal-organic frameworks (MOF), as a broad class of microporous materials, have attracted significantly scientific and technical attention due to their adjustable pore size and shape, as well as designable structures20-24. This character of MOF makes them promising for the design of new solid ionic conductors by loading conductive ILs into the pores of MOFs. At present, combining ILs and MOFs (ILs inside MOFs’ pores, denoted as IL@MOF) to generate new type of ionic hybrid composite has attracted wide consideration25. Fujie et al26 studied a type of low temperature

ionic

conductor

by

incorporating

1-ethyl-3-methylimidazolium

bis[(trifluoromethyl)sulfonyl]imide, [Emim][NTf2] within ZIF-8. Chen et al27 reported the optimum

ionic

conductivity

of

1.67×10˗3

S·cm˗1

obtained

at

150

℃

by

loading1-ethyl-3-methylimidazolium chloride, [Emim][Cl] into the pores of UiO-67. Dutta et al 28-29

proposed that MOF-IL composites working as fillers which dispersed in the polymer matrix

of poly (vinylidene fluoride-co-hexafluoropropylene) (PVdf-HFP) could enhance the electrochemical properties of nanocomposite system. The researches on IL@MOF conductive composites make full use of the advantage of IL and MOF materials. However, the research on 3



combining ILs with MOF to form ionic conductive materials is still insufficient. On the other hand, due to the randomness of ILs selection, there are some improvements in conductivity of IL@MOF composites based on current research, this area has great study space and application potential for various electrochemical devices. In this work, two ILs with high conductivity, 1-ethyl-3-methylimidazolium thiocyanate ([Emim][SCN]) and 1-ethyl-3 methylimidazolium dicyanamide ([Emim][DCA]), were introduced into the pores of a high stability MOF material, MIL-101 (Cr). The working temperature of IL@MOF was recorded from 150 to 25 ℃. The experimental results showed that the hybrid composites exhibit high ionic conductivity, low activation energy and excellent cycling performance. The results prove that the IL@MOF hybrid composites can be used as promising ionic-conductors.

EXPERIMENTAL SECTION Materials All chemicals were obtained from commercial sources directly and without further purification unless otherwise mentioned. Chromium (Ⅲ) nitrate nonahydrate (Cr(NO3)3·9H2O, 99.5%) was purchased from Sigma-Aldrich Co.(USA). Terephthalic acid (H2bdc, 98%) was purchased from TCI Co. (Japan). Hydrofluoric acid (HF, 40 wt %), ammonium fluoride (NH4F), methanol and ethyl acetate were obtained from Sinopharm Chemical Reagent Co., Ltd (China). ILs, [Emim][SCN] and [Emim][DCA] were purchased from Linzhou Branch can Material Technology Co., Ltd (China). Before using, all the ILs were washed by ethyl acetate for seven 4


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times then vacuuming drying over 10 h at 60 ℃. The water content of the all ILs was measured using Karl-Fisher titration and found to be less than 50 ppm. Preparation of MIL-101 (Cr) MIL-101 was prepared by solvothermal reaction according to the previous report

30-31

after

slight modification. Cr(NO3)3·9H2O (0.8 g, 2 mmol), H2bdc (0.332 g, 2 mmol) and HF (100 μL) were dissolved into deionized water (H2O, 14 mL), then transferred to a Teflon-lined stainless steel autoclave. The autoclave was heated to 220 ℃ in an oven and maintained for 24 h. After natural cooling to room temperature, the resulted green powder (MIL-101) was collected by centrifugation, then washed with deionized water for 5 times, and finally treated by hot ethanol at 60 ℃ for 10 h. After that, the precipitate was obtained and further purified by dispersing in 0.03 M NH4F aqueous solution at 60 ℃ for 12 h to eliminate the un-reacted reactants. Finally, the green power was washed with water for 6 times and further vacuuming dried overnight at 150 ℃. Preparation of IL@MOF [Emim][SCN] and [Emim][DCA] was vacuuming dehydrated at 60 ℃ for 12 h. The MIL-101 products were vacuuming activated at 120 ℃ for 12 h to remove guest molecules. IL@MOF was prepared by the impregnation-evaporation method. ILs theoretically occupied the volume of the pores at loadings of 25%, 50%, 75%, 100%, respectively. The volume occupancy was calculated by the pore volume of MIL-101 (1.56 mL/g). In one typical synthesis, 156 μL [Emim][SCN] were dissolved in 6 mL absolute methanol in an empty glass container. After 5



completely dissolving, 100 mg dehydrated MIL-101 was added to the solution, then magnetic stirred at 60 ℃ until methanol evaporated completely. The final green power product was dried in vacuum at 60 ℃ overnight and this sample (156 μL [Emim][SCN]@100 mg MIL-101) was donated as ES100@M. A similar process was adopted for the preparation of ESx@M (x = 25, 50, 75) and [Emim][DCA]@MIL-101 (symbolized as EDy@M, y = 50, 100). Characterization The powder X-ray diffraction (PXRD) patterns of the samples were recorded on a Bruker D8 Advanced Diffractometer using Cu-Kα radiation (λ = 0.1541874). Transform infrared spectroscopy (FT-IR) spectra were recorded using a Thermo Nicolet 380 spectrometer with pressed KBr pellets under the wave-numbers between 400 and 4000 cm˗1. Nitrogen adsorption-desorption isotherms were acquired at 77 K on a Quantachrome Autosorb-iQ instrument. Each sample was degassed at 105 ℃ for 12 h before measurement. The scanning electron microscope (SEM) morphology was obtained using a SIRION-100 instruments. Transmission electron microscope (TEM) images were taken on a JEM-2100F instrument. The thermal gravimetric analysis (TGA) was performed on a TG/DTA6300 (SII) thermal analyzer with the temperature range between 30 to 700 ℃ and a heating rate of 10 ℃/min˗1 under N2 atmosphere. Elemental analysis (EA) was recorded using Vario EL cube of CHNS. Pellet Pressing and Conductivity Measurement Within an argon-filled glove box, the electrolyte materials (IL@MOF, about 100 mg) were placed in a Kapton washer and sandwiched between PTFE sheets, and pressed under a pressure 6


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of 0.5 MPa for 2 min to obtained the pellet. The pellet using for conductivity measurements was 6 mm in diameter and about 1.5 mm in thickness. Then, both sides of the pellet were attached to silver wires with silver paste and sealed in a glass chamber by a rubber plug. The temperature-dependent conductivities of MOF and IL@MOF were tested through alternating current (a.c.) impedance analysis with a quasi-four-probe method. The test frequency range is1~4 MHz, and the disturbance voltage is 100~200 mV. In order to eliminate the absorbed trace water, which may have an influence on ionic conductivity, the pellet was kept under 150 ℃ for 6 h. After that, the conductivity of each sample was recorded from 150 to 25 ℃. The overall conductivity (σ / S·cm˗1) of the sample was calculated using the equation (1): σ = L/RS

(1)

Where σ is the overall conductivity, L (m) is the thickness of the pellet, R (Ω) is the measured impedance, S (m2) is the area of the pellet. The ionic conductivities of all the samples show linear Arrhenius behavior, which increase with the rising temperature. The activation energy (Ea/eV) for conductivity calculated by fitting conductivity data to Arrhenius equation: σT = exp(-Ea/kBT)

(2)

Where kB (J/K) is Bolzmann constant, T (K) is temperature. RESULTS AND DISCUSSION Characterization Powder X-ray diffraction patterns (PXRD) were used to confirm the structure of the composites. As shown in Figure1, the PXRD patterns of MIL-101 show that almost all the main

7



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diffraction peaks are observed in accordance with the simulated pattern. The main diffraction peaks of the composites conform to the parent MIL-101, suggesting that the crystal structure of MIL-101 remained stable and intact after [Emim][SCN] incorporating into the pores of MIL-101. Meanwhile, the relative intensities of peaks at low 2θ angles decrease with increasing the amounts of [Emim][SCN]. It suggested that the electron density inside the pores of MIL-101 changed after introducing [Emim][SCN]. The results were attributed to the disordered distribution of IL that produced background diffraction and decreased the diffraction of parent MIL-101. The similar changes occurred on other IL incorporated MOF composites in the relative intensity of corresponded peaks32-34.

Figure 1. (a) PXRD patterns of simulated MIL-101, MIL-101, ES25@M, ES50@M, ES75@M and ES100@M at room temperature. (b) N2 sorption isotherms of IL@MOF at 77 K.

To further identify the pore characteristics of loading [Emim][SCN] into the pore of MIL-101,

N2

adsorption-desorption

isotherms

were

tested

for

parent

MOF

and

[Emim][SCN]@MIL-101 samples with various loadings at 77 K. As shown in Figure 1b, all the isotherms show type I adsorption curve, the BET surface area of parent MIL-101 is measured to be 3056 m2/g, basically agreed with the reported value30. Moreover, compared with the parent 8


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MIL-101, the surface area and pore volume of [Emim][SCN]@MIL-101 samples reveal a significant decrease (from 3056, 1497, 495, 83 to 28 m2/g, 1.56 to 0.77, 0.29, 0.087 and 0,036 m3/g, respectively), as showed in Table 1. The pore size distribution, as shown in Figure 2, also reveals the similar phenomena. It suggests that [Emim][SCN] have been encapsulated inside the pores of MIL-101. Table 1. Structural Properties of parent MIL-101 and [Emim][SCN]@MIL-101 samples

Samples

BET surface Area (m2/g)

Pore Volume (cm3/g)

MIL-101

3056

1.56

ES25@M

1497

0.77

ES50@M

495

0.29

ES75@M

83

0.087

ES100@M

28

0.036

Figure 2. DFT pore size distributions of (a) MIL-101, (b) ES25@M, (c) ES50@M, (d) ES75@M, (e) ES100@M using data measured with N2 at 77 K.

To further confirm the presence of [Emim][SCN] encapsulated inside the pores of MIL-101, 9



FTIR spectra (Figure 3) of parent MIL-101, various concentration of [Emim][SCN]@MIL-101 samples and [Emim][SCN] were recorded. The strong absorption band between the region of 1300 and 1750 cm˗1 belongs to the vibration of carboxyl, which can be found in MIL-101 and both of the composites. The absorption between 1020 and 1160 cm˗1 could be assigned to Cr-O vibration of MIL-101. These two absorption bands can also be observed in the spectrum of [Emim][SCN]@MIL-101 composites, indicating that the structure of MIL-101 remains the same after incorporation. The broad absorption band at 1062 cm˗1 attributed to C-H bending vibration of phenyl of MIL-101 become sharper and exhibit some blue shift with the increasing of loading amount of [Emim][SCN], indicating that there was interaction between [Emim][SCN] and MIL-101, and it goes stronger as the [Emim][SCN] amount went higher. The absorption band at 840 cm˗1 is attributed to the vibration of S-C in [SCN]˗, which can be observed in [Emim][SCN] and its corresponded composites. These phenomena demonstrated that [Emim][SCN] was indeed embedded inside the pores of MIL-101.

Figure 3. FTIR spectra of (a) MIL-101, (b) ES25@100, (c) ES50@100, (d) ES75@100, (e) ES100@100, (f) 10


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[Emim][SCN]

In Figure 4, SEM and TEM images show that the morphology and crystal sizes of ES100@M and ED100@M are similar to parent MIL-101. The observations demonstrated that [Emim][SCN] and [Emim][DCA] were successfully introduced into the pores of MIL-101 and the structure of MIL-101 was intact after the synthetic process.

Figure 4. SEM and TEM images of (a1-a2) pristine MIL-101, (b1-b2) ES100@M, (c1-c2) ED100@M.

TGA measurements of parent MIL-101, [Emim][SCN]@MIL-101 and [Emim][SCN] were carried out to further check the existence of [Emim][SCN] inside the porous MIL-101, as shown in Figure 5. Before measuring, all samples were treated at 105 ℃ for 10 h to remove the residual solvent and water. The TGA patterns show two steps of weight loss. The first step could be assigned to the expulsion of coordination water within the temperature range of 30 to 362 ℃. The second step, ranging from 362 to 545 ℃, could be attributed to the collapse of the MIL-101 framework. [Emim][SCN] remain stable until the temperature reached 220 ℃, then decomposed 11



as a sharp weight loss taking place. For all [Emim][SCN]@MIL-101 samples, they are thermal stable enough to resist high temperature up to 215 ℃. Then it also reveal two steps of weight loss: the first step (from 215 to 407 ℃) is attributed to the decomposition of incorporated [Emim][SCN] which is a little lower than original [Emim][SCN]. The second step (> 407 ℃) could be assigned to the collapse of framework of MIL-101, which was higher than parent MIL-101. This phenomenon of the rising collapse temperature could be attributed to the confinement effect of IL inside the pores of MIL-101.

Figure 5. Thermal gravimetric analysis (TGA) curves for MIL-101, ES25@M, ES50@M, ES75@M, ES100@M and [Emim][SCN].

Elemental analysis (EA) was employed to determine the amount of loaded IL in the IL@MOF composites (Table 2). The results reveal the elemental S ratio (mass fraction) is almost the same as the calculated values based on the preparation process (ρ([Emim][SCN]) = 1.11684 g/mL, 25 ℃), indicating that almost all the [Emim][SCN] was incorporated into the pore of MIL-101. Table 2. Mass values and Results of EA for MIL-101 and various [Emim][SCN]@MIL-101 samples. Calculated values are on the mass fraction based on the preparation process. 12


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IL@MOF MIL-101/mg

[Emim][SCN]

S / w%

[Emim][SCN]/ w%

μL / mg

Calcd / Found

Calcd / Found

MIL-101

100

0

0/0

0/0

ES25@M

100

39 / 45.57

5.93 / 6.31

31.30 / 33.31

ES50@M

100

78 / 91.14

9.04 / 9.28

47.68 / 48.98

ES75@M

100

117 / 136.70

10.95 / 11.78

57.75 / 62.18

ES100@M

100

156 / 182.27

12.24 / 12.29

64.57 / 64.87

Ionic conductivity analysis At room temperature, original [Emim][SCN] and [Emim][DCA] had high ionic conductivity of 2.21×10˗2 S·cm˗1 and 1.89×10˗2 S·cm˗1, respectively35-36. On the other hand, the COSMO volumes of [Emim]+, [SCN]˗ and [DCA]˗ were 155.8 Å3, 69.5 Å3 and 101.8 Å3, respectively. On the other hand, the size of longest side of [Emim]+, [SCN]˗ and [DCA]˗ were 7.486 Å, 2.850 Å, 4.531 Å. Meanwhile, MIL-101 had two types of spherical cages, which have hexagonal window (about 14.7 Å) in the bigger cages (φ= 3.4 nm) and pentagonal window (about 12 Å) in the smaller cages (φ= 2.9 nm). This means the windows in MIL-101 were large enough to allow [Emim][SCN] and [Emim][DCA] to incorporate into the pores. The ionic conductivity of the composites and MIL-101 were studied by alternating current (a.c.) impedance measurements under temperatures ranging from 150 to 25 ℃ based on testing pellet shape samples. As shown in Figure 6a, Nyquist plots of ES100@M from 150 to 90 ℃ reveal good Debye semicircles or arcs shape curves. Similar plots trend of other samples could 13



also be found, as shown in Figure 7 and Figure 8 a, b. On the contrary, the resistance of ES100@M decreases with the temperature increasing. Moreover, the ionic conductivity increases with the temperature increasing. Based on the measurements, the ionic conductivity could be calculated to be about 1.15×10˗3 S·cm˗1 at 25 ℃ and could reach 6.21×10˗3 S·cm˗1 at 150 ℃ (Figure 6c, Table 3). As shown in Figure 6b, the ionic conductivities of all [Emim][SCN]@MIL-101 composites exhibit linear Arrhenius behavior, which is the conductivities increased linearly with the temperature increasing.

Figure 6. (a) Temperature-dependent Nyquist plots of ES100@M from 150 to 90℃. (b) Arrhenius plots of various concentration [Emim][SCN]@MIL-101samples. (c) The change of ionic conductivity for various concentration [Emim][SCN]@MIL-101samples with the increase of temperature. (d) Cycle testing of the temperature-dependent conductivity of ES100@M. 14


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The conductivity value of ES100@M is about 2.4 times higher than ES75@M, and one and two orders of magnitude larger than that of ES50@M and ES25@M at 150 ℃. In comparison, the conductivity of MIL-101, calculated to be about 7.38×10˗9 S·cm˗1 at 150 ℃ and agreed well with the previous report14, was so small that it could almost be ignored. With increasing the amounts of [Emim][SCN] (from ES25@M to ES100@M), the conductivity of [Emim][SCN]@MIL-101 composites

increase.

This

phenomenon

suggested

that

the

ionic

conductivity

of

[Emim][SCN]@MIL-101 was strongly associated with the amount of [Emim][SCN] inside the pores of MIL-101, and was agreed with previous reports1,14,24-25. The reason for this phenomenon may attribute that more [Emim][SCN] in the pores of MIL-101, more continuous conduction pathway would be generated. In addition, the recycling performance was also investigated. The result shows that, even after 10 times repetitions of ionic conductivity measurement of ES100@M composites at 150 ℃, the conductivity decreased only a little. The result meant that ES100@M had a good cycling performance, which benefited its practical application as solid electrolyte. Table 3. Partial data for ionic conductivity of various concentration of [Emim][SCN]@MIL-101, [Emim][DCA]@MIL-101 and MIL-101 samples at different temperatures.

σ (S·cm-1) T(℃) ES100@M

ES75@M

ES50@M

ES25@M

ED100@M

ED50@M

MIL-101

150℃

6.21×10-3

2.61×10-3

1.77×10-4

4.35×10-5

2.45×10-3

9.93×10-5

7.38×10-9

100℃

3.30×10-3

1.23×10-3

5.66×10-5

5.52×10-6

1.49×10-3

4.00×10-5

---

50℃

1.68×10-3

5.13×10-4

1.67×10-5

6.68×10-7

7.09×10-4

1.10×10-5

---

15



25℃

1.15×10-3

3.34×10-4

7.64×10-6

2.09×10-7

4.14×10-4

Page 16 of 22

4.12×10-6

---

Figure 7. Nyquist plots of (a) ES100@M from 80 to 25℃, (b) ES75@M from 150 to 90℃, (c) ES75@M from 80 to 25℃, (d) ES50@M from 150 to 90℃, (e) ES50@M from 80 to 25℃, (f) ES25@M from 150 to 25℃

To verify the feasibility of this synthesis method in obtaining conductive nanocomposites, [Emim][DCA]@MIL-101 composites was also prepared. As shown in Figure 8, the 16


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electrochemical properties of [Emim][DCA]@MIL-101 composites are similar to those of [Emim][SCN]@MIL-101 composites. On the other hand, the conductivity of ED100@M was 2.45×10˗3 S·cm˗1 at 150 ℃, which is lower than that of ES100@M. These results were comparable to the reported conductivity value of [Emim][Cl]@UiO-67, which was 2.45×10˗3 S·cm˗1 at 200 ℃27, which proved the feasibility of this method.

Figure 8. (a) Temperature-dependent Nyquist plots of ED100@M from 150 to 25℃. (b) Temperature-dependent Nyquist plots of ED50@M from 150 to 25℃. (c) Arrhenius plots of ED100@M and ED50@M. (d) The change of ion conductivity ED100@M and ED50@M with the increase of temperature.

The activation energy (Ea) of [Emim][SCN]@MIL-101 and [Emim][DCA]@MIL-101 composites were calculated using equation (2). The values were 0.17 ev (ES100@M), 0.21 ev 17



(ES75@M), 0.30 ev (ES50@M), 0.50 ev (ES25@M), 0.18 ev (ED100@M), 0.31 ev (ED100@M) and 0.82 ev (MIL-101), respectively. The results showed that ES100@M and ED100@M had lower Ea, which indicated that these hybrid composites were fast-ionic conductor. After the conductive measurements, ES25@M - ES100@M samples were washed by methanol for many times, and then sent for PXRD and BET measurements. The results are showed in Figure 9, and consistent with pristine MIL-101. It reflected that the MOF crystal structures remained the same and intact during the synthetic process and testing process, which was benefit for practical application.

Figure 9. (a) PXRD patterns of MIL-101, ES25@M-washed, ES50@M-washed, ES75@M-washed, ES100@M-washed at room temperature. (b) N2 sorption isotherms for MIL-101 and washed samples of various concentration [Emim][SCN]@MIL-101, (A) means adsorption and (D) means desorption.

CONCLUSION In summary, a series of ionic conductive materials have been synthesized by loading [Emim][SCN] and [Emim][DCA] into the pores of MIL-101. The ionic conductivity of ES100@M samples could reached up to 6.21×10˗3 S·cm˗1 at 150 ℃. At room temperature, it could 18


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also reached up to 1.15×10˗3 S·cm-1, which met the practical application requirements (>10˗3 S·cm˗1) for solid electrolytes. The higher ionic conductivity, lower Ea and good cycling performance all made this type of material as potential excellent candidate for electrochemical devices. Moreover, the preparation method was feasible, thus provided a promising method for other IL and MOF producing novel composite electrolytes for further application in electrochemical area.

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Abstract graphic

Synopsis: Developing novel and high conductivity solid materials for electrochemical equipments is essential in green chemical engineering.

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Ionic Liquid Incorporated Metal Organic Framework for High Ionic

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