Ionic conductive polymer gel film

Kanno, R., Tadokoro, S., Takamori, T. and Hattori, M. (1996). Linear approximate dynamic model of IPMC (ionic conducting polymer gel film) actuator, in Proceedings of the IEEE International Conference on Robotics and Automation (Minneapolis, MN), pp. 219-225. 

Tadokoro, S., Mruakami, T., Fuji, S., et al. (1997) An elliptic friction drive element using an ICPF (ionic conducting polymer gel film) actuator, IEEE Control Systems, 17 (3), 60-8. 

Many approaches have been developed for the production of ionic liquid-polymer composite membranes. For example, Doyle et al. [165] prepared RTILs/PFSA composite membranes by swelling the Nafion with ionic liquids. When 1-butyl, 3-methyl imidazolium trifluoromethane sulfonate was used as the ionic liquid, the ionic conductivity ofthe composite membrane exceeded 0.1 S cm at 180 °C. A comparison between the ionic liquid-swollen membrane and the liquid itself indicated substantial proton mobility in these composites. Fuller et al. [166] prepared ionic liquid-polymer gel electrolytes by blending hydrophilic RTILs into a poly(vinylidene fiuoridej-hexafluoropropylene copolymer [PVdF(HFP)] matrix. The gel electrolytes prepared with an ionic liquid PVdF(HFP) mass ratio of 2 1 exhibited ionic conductivities >10 Scm at room temperature, and >10 Scm at 100 °C. When Noda and Watanabe [167] investigated the in situ polymerization of vinyl monomers in the RTILs, they produced suitable vinyl monomers that provided transparent, mechanically strong and highly conductive polymer electrolyte films. As an example, a 2-hydroxyethyl methacrylate network polymer in which BPBF4 was dissolved exhibited an ionic conductivity of 10 S cm at 30 °C. 

On the other hand, we have reported the preparation of gel-type polymer electrolytes using polyether/salt hybrid oligomers [12]. A network-type PPO film was swollen with the PPO/triiluoromethylsulfonamide Uthium salt hybrid. The obtained gel containing 50 wt% of PPO/salt hybrid showed a low Tg of —62°C. The PPO/salt hybrid behaved as not only an added salt but also a plasticizer. The ionic conductivity was over 10 S cm at room temperature. Furthermore this gel electrolyte showed a favorable lithium-ion transference number of 0.7-0.8. 

Several polymer gel electrolytes were prepared by changing the mixing ratio of ZILs to polymer. The polymer gel electrolytes were obtained as translucent films up to 80 wt% of the ZIL/LiTFSI content. When the content of the ZIL/LiTFSI mixture was less than 40wt%, they were obtained as flexible but white films. Figure 27.4 shows the effect of ZIL/LiTFSI mixture content on the ionic conductivity for polymer gel electrolytes. The ionic conductivity of these polymer gel... 

Gel and solid polymer electrolytes aim to combine the function of the electrolyte and separator into a single component to reduce the number of parts in an ES and increase the potential window through the higher stability offered by a polymer matrix. A gel electrolyte incorporates a liquid electrolyte into a microporous polymer matrix that holds in the liquid electrolyte through capillary forces, creating a solid polymer film. The chosen separator must be insoluble in the desired electrolyte and provide adequate ionic conductivity. Non-polar rigid polymers such as PTFE, PVA, PVdF, and cellulose acetate offer good ion conductivity when used as gel electrolytes [114]. Based on the data in Table 4.9, the ionic conductivity of EtMeIm+Bp4 is 14 mS.cm". Ionic conductivity of the same imidazolium salt used as a gel electrolyte in a PVdF matrix retains 5 mS.cm [115]. 

Cyanate-containing EO units can also cross-link with polyol-containing EO units by heating, to form a gel polymer electrolyte. Its film is transparent and flexible and has high mechanical strength. When plasticized with wt% 1.5 M LiC104 solution in PC, its ionic conductivity at 60°C is not high, 1.51 x 10 S/cm, which may be associated with the synthesis process. 

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