Electrolytes for supercapacitors

Ma, G., Feng, E., Sun, K., Peng, H., Li, J., Lei, Z., 20i4. A novel and high-effective redox-mediated gel polymer electrolyte for supercapacitor. Electrochim. Acta 135,461-466. 

Sankar, K. V., D. Kalpana, and R. K. Selvan. 2012. Electrochemical properties of microwave-assisted reflux-synthesized Mn304 nanoparticles in different electrolytes for supercapacitor applications. Journal of Applied Electrochemistry 42 463-470. 

Perricone, E., M. Chamas, J. C. Lepretre et al. 2013. Safe and performant electrolytes for supercapacitor. Investigation of esters/carbonate mixtures. Journal of Power Sources 239 217-224. 

Pohlmann, S., R. S. Kuhnel, T. A. Centeno, and A. Balducci. 2014. The influence of anion-cation combinations on the physicochemical properties of advanced electrolytes for supercapacitors and the capacitance of activated carbons. ChemElectroChem 1 1301-1311. 

Brandt, A., C. Ramiiez-Castro, M. Anouti, and A. Balducci. 2013. An investigation about the use of mixtures of sulfonium-based ionic liquids and propylene carbonate as electrolytes for supercapacitors. Journal of Materials Chemistry A 1 12669-12678. 

Fang, X., and D. Yao. 2013. An overview of solid-like electrolytes for supercapacitors. Proceedings oftheASME 2013 International Mechanical Engineering Congress and Exposition, San Diego, California. 

Samui, A. B., and P. Sivaraman. 2010. Solid polymer electrolytes for supercapacitors. In Polymer Electrolytes Fundamentals and Applications, C. Sequeira and D. Santos (Eds), 431—470, Cambridge, UK Woodhead Publishing Limited. 

Sudhakar, Y. N., M. Selvakumar, and D. K. Bhat. 2013. LiC104-doped plasticized chitosan and poly(ethylene glycol) blend as biodegradable polymer electrolyte for supercapacitors. Ionics 19 277-285. 

Liew, C. W., S. Ramesh, and A. K. Arof. 2014. Good prospect of ionic liquid based-polyfvinyl alcohol) polymer electrolytes for supercapacitors with excellent electrical, electrochemical and thermal properties. International Journal of Hydrogen Energy 39 2953-2963. 

Liew, C. W, and S. Ramesh. 2014. Comparing triflate and hexafluorophosphate anions of ionic liquids in polymer electrolytes for supercapacitor applications. Materials 7 4019 033. 

Pandey GP, Kumar Y, Hasami SA (2010) Ionic liquid incorporated polymer electrolytes for supercapacitor application. Indian J Chem 49A 743-751... 

Now that supercapacitors are better understood, the next objective for simulations consists in proposing optimized electrode - electrolyte combinations or new storage concepts. To this end, high-throughput screening seems like a promising way. Indeed, in the spirit of what is currently done in materials science for photocatalysts " and for battery electrodes or electrolytes. First steps towards this direction have been made by Balducci et in order to predict via computation and to test experimentally the best electrolytes for supercapacitors. 

PIL-based electrolytes exhibit intermediate conductivity compared to conventional electrolytes (especially in ACN) and AILs, but they might have interesting conductivity at low temperatures [135]. Additionally, some works have indicated that in PIL-based electrolytes, ruthenium oxide [136], as well as activated carbon [137], might exhibit pseudo-capacitance due to the labile proton in PILs, which participates on the fast redox reactions at the electrode/electrolyte interface. Taking into account these properties, PILs could be interesting electrolyte candidates in order to use them as electrolytes for supercapacitors. 

Considering the promising properties, especially their cost, hazard, and the risks of these DESs series, their introduction as safer electrolytes could represent an important challenge for the realization of environmentally friendly EDLCs operating at high temperatures. The study of the original ions adsorption mechanism of desolvated lithium ions provides an interesting opportunity for fundamental smdies even beyond the applicative interest of DESs as electrolytes for supercapacitors. 

Abstract This chapter reviews state-of-the-art development in the field of sohd polymer electrolytes for supercapacitors and discusses their specific features. The main themes discussed are based on individual series of sohd polymer electrolytes such as ion exchange resins, polyethers, polymer gels and nanocomposites, followed by supercapacitor types, electrode types and supercapacitors reported under various kinds of sohd electrolytes. This is followed by information on hybrid supercapacitors and current research activities and finally a conclnsion. 

For supercapacitors made with SWCNT, a specific capacitance of around 80 F/g was observed in liquid aqueous electrolytes. For supercapacitors made with thin sprayed films using the same SWCNT material, the specific capacitance was around 120 F/g. This indicated that wetting was better in thin CNT films, increasing the effective surface area. This was valid even in the case of a gel electrolyte. The capacitance was found to increase linearly for the liquid electrolyte, whereas saturation occurred for the gel electrolyte, which indicated a limited penetration into the gel network. From the study it was concluded that the optimum thickness of the CNT film should be around 2 jm for the gel electrolyte. The RC constants for the supercapacitor were around 0.5 s for aqueous electrolytes and 0.1 and 0.3 s for the organic electrolyte at 1 and 3 V respectively. The power density obtained in the organic electrolyte was about 70 kW/kg. The concept of printed power without a current collector offers a new platform for all kinds of lightweight devices. 

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