Thermoregulated polyoxometalate-based ionic-liquid gel electrolytes

Abstract

A series of vanadium-substitutive polyoxometalate-based ionic liquids, [PyPS] 6 PW 9 V 3 O 40 , [PyPS] 4 PW 11 VO 40 , [PyPS] 4 PMo 11 VO 40 and [PyPS] 7 P 2 W 17 VO 62 , bearing sulfo-group grafted ammonium (PyPS), are transformed to reversible thermal-response gel-type compounds. Interestingly, these geltype compounds exhibit an obvious increase in their conductivity during the reversible phase transformation, which means that they are a novel series of reversible thermal-response gelation electrolytes. The relationship between the component elements of the polyoxometalate-based ionic liquids and their electrochemical performances has been studied. The Dawson-type compound ([PyPS] 7 P 2 W 17 VO 62 ) has a higher conductivity than the Keggin-type one ([PyPS] 4 PW 11 VO 40 ) with the same number of vanadium atoms in the structure. What's more, the W-containing compounds ([PyPS] 6 PW 9 V 3 O 40 and [PyPS] 4 PW 11 VO 40 ) have higher conductivities than the Mo-containing one ([PyPS] 4 PMo 11 VO 40 ).

Catalytic synthesis of chloroacetates with thermoregulated ionic liquids based on vanadium-substituted polyoxometalate

“…The strong diffraction peaks at 7-12 can be considered as the POM anion structure, they were also observed in the XRD pattern of [TEAPS] 5 PW 10 V 2 O 40 in the small angle area, suggesting that the POM anion structure existed in the hybrid material. 30,34 However, [TEAPS] 5 PW 10 V 2 O 40 exhibited a broad diffraction peak in the range of 2q ¼ 12-40 , which revealed its amorphous state, which was consistent with the gel-type phase at room temperature. It is reported that an organized layer-type structure existed in this series of compounds, and the weak connections of the layers leaded to the appearance of smectic gel-type phase.…”

“…This phenomenon could be explained that the electrostatic between the organic cation and heteropolyacid anions were weakened as the anion-anion distance increases. 34 Furthermore, some other characteristic peaks at 1160 cm À1 , 2977 cm À1 were assigned to n S]O and n C-H , respectively. 34 Since the characteristic peaks still existed, we can infer that these compounds still retained Keggin-type structure of heteropolyanion without decomposition.…”

“…34 Furthermore, some other characteristic peaks at 1160 cm À1 , 2977 cm À1 were assigned to n S]O and n C-H , respectively. 34 Since the characteristic peaks still existed, we can infer that these compounds still retained Keggin-type structure of heteropolyanion without decomposition. At the same time they maintained structure of sulfonic-functionalized triethylamine cation when TEAPS was added.…”

“…Those four well-known characteristic bands proved the presence of Keggin-type heteropoly anion. 34,35 Compared with pure heteropolyacids, the M-O d and P-O a vibration frequencies of POM-ILs were decreased when sulfogroup graed ammonium ions were added to POM. This phenomenon could be explained that the electrostatic between the organic cation and heteropolyacid anions were weakened as the anion-anion distance increases.…”

The synthesis and electrical properties of hybrid gel electrolytes derived from Keggin-type heteropoly acids and 3-(pyridin-1-ium-1-yl)propane-1-sulfonate (PyPs)

“…[17][18][19][20][21] Various hybrid gels were developed using POMs and ILs such as Nmethyl imidazolium-1-(3-sulfonic group) propyl (MIMPS), 3-(pyridine-1-ium-1-yl)propane-1-sulfonate (PyPs), 1-(3-sulfonic group) triethylamine (TEAPS) and N-propyl-N-methylpiperidinium hexauorophosphate. [22][23][24][25][26][27][28][29][30] Several heteropoly acids (HPAs) and polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG) hybrids were also recently reported. 28 Herein, we report the synthesis and structural, chemical and electrochemical characterization of hybrid gel electrolytes based on recently developed 3-(pyridin-1-ium-1-yl)propane-1sulfonate (PyPs) 24 IL and H 3 PW 11 MoO 40 , H 4 PMo 11 VO 40 and H 5 PMo 11 V 2 O 40 for potential electrochemical energy conversion and storage applications.…”