Sohd polymer electrolyte

The successfiil synthesis of a transparent soHd polymer electrolyte (SPE) based on PEO and alkoxysilanes has been reported (41). The material possessed good mechanical properties and high electrical conductivity (around 1.8 x 10 S/cm at 25°C) dependent on the organic—inorganic ratio and PEO chain length. 

Three types of electrochemical water-spHtting processes have been employed (/) an aqueous alkaline system (2) a soHd polymer electrolyte (SPE) and (J) high (700—1000°C) temperature steam electrolysis. The first two systems are used commercially the last is under development. 

Solid Polymer E,kctroljte. The electrolyte in soHd polymer electrolyte (SPE) units is Nafion, a soHd polymer developed by Du Pont, which has sulfonic acid groups attached to the polymer backbone. Electrodes are deposited on each side of the polymer sheet. H" ions produced at the anode move across the polymer to the cathode, and produce hydrogen. The OH ions at the anode produce oxygen. These units have relatively low internal resistances and can operate at higher temperatures than conventional alkaline electrolysis units. SPE units are now offered commercially. 

As can be seen from Eigure 11b, the output voltage of a fuel cell decreases as the electrical load is increased. The theoretical polarization voltage of 1.23 V/cell (at no load) is not actually realized owing to various losses. Typically, soHd polymer electrolyte fuel cells operate at 0.75 V/cell under peak load conditions or at about a 60% efficiency. The efficiency of a fuel cell is a function of such variables as catalyst material, operating temperature, reactant pressure, and current density. At low current densities efficiencies as high as 75% are achievable. 

A second class of important electrolytes for rechargeable lithium batteries are soHd electrolytes. Of particular importance is the class known as soHd polymer electrolytes (SPEs). SPEs are polymers capable of forming complexes with lithium salts to yield ionic conductivity. The best known of the SPEs are the lithium salt complexes of poly(ethylene oxide) [25322-68-3] (PEO), —(CH2CH20) —, and poly(propylene oxide) [25322-69-4] (PPO) (11—13). Whereas a number of experimental battery systems have been constmcted using PEO and PPO electrolytes, these systems have not exhibited suitable conductivities at or near room temperature. Advances in the 1980s included a new class of SPE based on polyphosphazene complexes suggesting that room temperature SPE batteries may be achievable (14,15). 

Fig. 1. Configuration for a soHd polymer electrolyte rechargeable lithium cell where the total thickness is 100 pm.

Another factor also contributed to the appearance of new concepts in electrochemistry in the second half of the twentieth century The development and broad apphca-tion of hthium batteries was a stimulus for numerous investigations of dilferent types of nonaqueous electrolytes (in particular, of sohd polymer electrolytes). These batteries also initiated investigations in the held of electrochemical intercalation processes. 

The third concept is called the SPE cell (Fig. 9.4c). The term SPE stands for Sohd Polymer Electrolyte. In such cells, ions which convey electric... 

Choi, P., Bessarabov, D. G., Datta, R. (2004,). A simple model for sohd polymer electrolyte (SPE) water electrolysis. Solid State Ionics, 175(1), 535—539. 

Selvasekarapandian et al. studied soHd polymer electrolytes based on polyvinyl alcohol (PVA)/ammonium acetate using variable temperature H sohd-state MAS NMR. It was revealed that the proton Hne width decreases exponentially with the increase of temperature, and concluded that the NH4 ion is responsible for the proton conduction and the anionic motion is also involved in the conduction process at b her temperature [38],... 

In principle, three different electrolyte types can be distinguished liquid flow electrolytes (e.g., potassium hydroxide, sodium hydroxide, or their mixtures), immobihzed electrolytes (i.e., the Hquid electrolyte is fixed in a matrix or a gel), and anion-exchange polymer electrolytes (e.g., sohd polymer electrolytes in PEFCs as described above). 

Kraft A, Stadehnarm M, Wiinsche M, Blaxhke M (2006) Electrochemical destruction of oiganic substances in deionized water using diamond anodes and a sohd polymer electrolyte. Electrochem Commun 8 155-158... 

Ho KC, Hung WT (2001) An amperometric N02 gas sensor based on Pt/Nafion electrode. Sens Actuators B 79 11-18 Ho KC, Liao JY, Yang CC (2005) A kinetic study for electrooxidation of NO gas at a Pt/membrane electrode-apphcation to amperometric NO sensor. Sens Actuators B 108 820-827 Imaya H, Ishiji T, Takahashi K (2005) Detection properties of electrochemical acidic gas sensors using halide-halate electrolytic solutions. Sens Actuators B 108 803-807 Ives DJG, Janz GJ (eds) (1961) Reference electrodes theory and practice. Academic, New York, NY Jordan LR, Hauser PC, Dawson GA (1997) Humidity and temperature effects on the response to ethylene of an amperometric sensor utilizing a gold-Nafion electrode. Electroanalysis 9 1159-1162 Katayama-Aramata A, Nakajima H, Fujikawa K, Kita H (1983) Metal electrodes bonded on sohd polymer electrolyte membranes (SPE)—the behaviour of platinum bonded on SPE for hydrogen and oxygen electrode processes. Electrochim Acta 28 777-780... 

Initially, lithium polymer battery electrolytes were in the form of a dry sohd polymer electrolyte but it was found that performance could be improved by introducing gelled electrolyte into the separator system. Described by some as a gehonic electrolyte which is not a genuine polymer, these critics maintain that the batteries should be described as being plastic hthium ion and not hthium polymer. 

Bemardi DM, Verbmgge MW. A mathematieal model of the sohd-polymer-electrolyte fuel cell. J Electrochem Soc 1992 139 2477-91. 

Lalande, G., Tamizhmani, G., Cote, R. et al. 1995. Influence of loading on the activity and stabihty of heat-treated carbon-supported cobalt phthalocyanine electrocatalysts in sohd polymer electrolyte fuel ceUs./. Electrochem. Soc. 142 1162-1168. 

Another approach is the use of a sohd polymer electrolyte. These electrolytes are considered to have a safety advantage over the hquid electrolyte because of their lower reachvity with lithium and the absence of a volahle and sometimes hammable electrolyte. These electrolytes, however, have a lower conduchvity that must be compensated for by using thinner electrodes and separators and by having larger electrode areas. 

A device for tactile sensing has been proposed by Yamada and coworkers. PPy was deposited on comb-shaped microelectrodes and covered with a polyethylene glycol sohd polymer electrolyte containing LiC104 salt. The 30 pm PPy layer expanded 2 pm in 30 s, which, according to the authors, should be enough to be sensed (Yamada et al. 1998). 

Goujon LJ et al (2011) Flexible sohd polymer electrolytes based on nitrile butadiene rubber/poly (ethylene oxide) interpenetrating polymer networks containing either LiTFSI or EMITFSI. Macromolecules 44(24) 9683-9691, Available at http //pubs.acs.org/doi/abs/10.1021/ ma201662h. Accessed 22 Feb 2013... 

O. Savadogo, Emerging membranes for electrochemical systems (1) Sohd polymer electrolyte membranes for fuel cell systems, J. New Mater. Electrochem. Syst. 1(1), 47-66 (1998). 

Microsohd state batteries in the form of thin films partly avoid the irrterfaee eorrtact difficirlty and can be ttsed as devices in microelectronics. Recently, eonsiderable atterrtion has been focitsed on the preparation of solid state lithium batteries using sohd polymer electrolytes which are made from polymer complexes formed by hthirrm salts arrd polymer ethers. Ultrathin-film solid state lithirrm batteries have been fabricated using a thin solid polymer electrolyte film prepared by complexation of a plasma polymer and hthirrm perchlorate. ... 

For most polymer electrolyte fuel cell (PEFC) systems, unit cells are combined into a PEFC stack to achieve the voltage and power output level required for the appUcation. The unit cells normally use a membrane electrode assembly, consisting of a sohd polymer electrolyte with an associated gas-diffusion layer sandwiched between two bipolar plates. The bipolar plates make connections over the entire surface of one cathode and the anode of the next cell. These bipolar plates serve several functions simultaneously (1) they create channels for fuel, air, and water, (2) they separate the unit cells in the stack, (3) they carry current away from the cell, and (4) they support the membrane electrode assembly (Lee et al. 2006 Shao et al. 2007). 

While a battery separator s materials are usually inert and do not influence electrical energy storage or output, its properties can have an important influence on safety. There are three types commonly used [46] (i) high-temperature sohd-polymer electrolytes (SPEs) such as poly(ethylene oxide) (PEO), (ii) microporous shutdown separators, which are composed of poly(ethylene) (PE) or laminates of poly(propylene) (PP) and PE, (iii) gel polymers such as poly(vinyhdene fluoride), PVdF, and (iv) ceramic separators. Table 27.2 shows the types of separators used in secondary Hthium-based batteries. 

AUcock, H. R., Prange, R., Hartle, T. J., Poly(phosphazene-ethylene oxide) di-and triblock copolymers as sohd polymer electrolytes, Macromolecules, 2001, 34, 5463-5470. 

Q.M. Wu, J.F. Zhang, S.B. Sang, Preparation of alkahne sohd polymer electrolyte based on PVA-TiOj-KOH-HjO and its performance in Zn-Ni battery, J. Phys. Chem. Solids, 69 (2008) 2691-2695. 

Bernard , D.M. Water-balance calculations for sohd-polymer-electrolyte fuel cells. Journal of the Electrochemical Society, 137(11), 3344,1990. 

DOYLE, M. and NEWMAN, J., 1995. Analysis of transference number measurements based on the potentiostatic polarization of sohd polymer electrolytes. /. Electro-chem. Soc., 142(10), 3465-3468. 

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. 

Key words sohd polymer electrolytes, supercapacitors, ionic condnctivity, electrode materials, specific capacitance, internal resistance, cycle life. 

VASSAL, N., SALMON, E., FAUVARQUE, J.F., Electrochemical properties of an alkaline sohd polymer electrolyte based on P(ECH-co-EO), Electrochim. Acta, 2000,45,1527-32. 

J. Ennari, I. Neelov and F. Sundhohn. Molecular dynamics simulation of the structure of PEO based sohd polymer electrolytes. Polymer 41, 2000,4057. 

Jorissen J (2003), Electro-organic synthesis without supporting electrolyte possibilities of sohd polymer electrolyte technology , J Appl Electrochem, 33, 969-977. 

Vaghela S S, Ramachandraiah G, Ghosh P K and Vasudevan D (2002), Electrolytic synthesis of succinic acid in a flow reactor with sohd polymer electrolyte membrane ,/AppZ Electrochem, 32,1189-1192. 

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