Polypyrrole lithium batteries

Many industrial and academic laboratories have investigated doped polymers as improved positive electrodes in rechargeable lithium batteries. A common example is the battery formed by a lithium anode, a liquid organic electrolyte (e.g. LiC104-PC solution) and a polypyrrole film... 

Fig. 9.16 Cyclic behaviour of lithium batteries using standard pPy(C104) polypyrrole electrodes and modified pPy(DS) electrodes.

The benefit of a hybrid phase for the intercalation-deintercalation of mobile species such as Li+ cations is well illustrated by the study of conductive polymers such as polyaniline or polypyrrole intercalated into a V2O5 framework as potential electrode materials in lithium batteries [34]. For PANI/V2O5, an oxidative post-treatment performed under an oxygen atmosphere allowed the authors to compare the conductivity attributed to the polymer, as in absence of reduced cations, there was no electronic hopping between ions, and the conductive state was due only to the... 

The electrosynthesis of polythiophene (PT) from thiophene must be performed under extremely anhydrous conditions, quite in contrast to polypyrrole [334]. Polymerization of 3-methylthiophene and bithiophene is much less sensitive to water. The advantage of PT is a higher theoretical capacity and a very positive potential (cf. Table 7). It is for these reasons that its application as a positive electrode in rechargeable lithium batteries [335-338] and in a metal-free PPy/PT cell [339] has been considered. Derivatives such as dithienothiophene [340] or rra/is-l,2-di(2-thienyl)ethylene [341] have also been polymerized, but the polymer materials suffer from low theoretical capacities [337]. 

Recently Osaka et al [260] studied a lithium/ polypyrrole secondary battery system using PEO-LiC104 as a solid polymer electrolyte. The battery showed fairly high coulombic efficiency of about 95% with an output voltage of 3.0 V and performed very well for 1400 charge-discharge cycles after initial 100 scans required to reach optimum value. However, efficiency... 

Yang,Y,Wang,C.,Yue,B.,Gambhlr,S.,Too,C.O.,andWallace,G.G.(2012]. Electrochemically synthesized polypyrrole/graphene composite film for lithium batteries, Adv. Energy Mater, 2, pp. 266-272. 

Osaka, T., et al. 1997. Performances of lithium/gel electrolyte/polypyrrole secondary batteries. / Power Sources 68 392. 

Naoi, K., A. Ishijima, and T. Osaka. 1987. An improvement of battery performance of lithium batteries assembled with a polypyrrole cathode formed electrochemically with the aid of a nitrile rubber insulating film. J Electroanal Chem 217 (1) 203. 

Osaka, T., Momma, T., Nishimura, K. Kakuda, I., and Ishii, T., Application of solid polymer electrolyte to lithium/polypyrrole secondary battery system, J. Electrochem. Soc., 141, 1994-1998 (1994). 

Tang W, Gao XW, Zhu YS, Yue YB, Shi Y, Wu YP, Zhu K (2012) Coated hybrid of V2O5 nanowires with MWCNTs by polypyrrole as anode material for aqueous rechargeable lithium battery with excellent cycling performance. J Mater Chem 22 20143-20145... 

The belief that lithium batteries may be the best way to power electric vehicles (EVs) has strongly stimulated interest in hthium. New battery configurations continue to be developed. Pyrrole is a suitable electrode material for rechargeable lithium batteries. In a flat cell, polypyrrole and Hthium films are sandwiched together. In a cylindrical cell the two films are wound concentrically. 

Polymers. Electronically conductive polymers may also be used as cathode materials in rechargeable lithium batteries. The most popular polymers are polyacetylene, polypyrrole, polyaniline, and polythiophene, which are made conductive by doping with suitable anions. The discharge-charge process is a redox reaction in the polymer. The low specific energy, high cost, and their instability, however, make these polymers less attractive. They have been used in small coin-type batteries with a lithium-aluminum alloy as the anode. 

Polypyrrole (PPy) is another intensively studied conducting polymer used for energy storage applications. PPy has been synthesized from the polymerization of pyrrole by either electrochemical or chemical oxidation method [16, 19]. Since it is difficult to n-dope PPy, p-type PPy as positive electrode material is the common choice reported in lithium batteries. Typically, the specific energy of PPy falls in the range of 80-390 Wh kg with the open-circuit voltage of 3-4 V. One of ffie main drawbacks of PPy as cathode material is its relatively low theoretical capacity. 

Sun M, Zhang S, Jiang T, Zhang L, Yu J. Nano-wire networks of sulfur-polypyrrole composite cathode materials for rechargeable lithium batteries. Electrochem Commun 2008 10(12) 1819-22. 

Sodium dodecyl sulfate has been used to modify polypyrrole film electrodes. Electrodes synthesized in the presence of sodium dodecyl sulfate have improved redox processes which are faster and more reversible than those prepared without this surfactant. The electrochemical behavior of these electrodes was investigated by cyclic voltametry and frequence response analysis. The electrodes used in lithium/organic electrolyte batteries show improved performance [195]. 

Prototypes of lithium/polypyrrole batteries are under study in various laboratories and low rate, small size versions of these batteries have reached an advanced development stage in European (Munstedt et al, 1987) and Japanese (Sakai et al, 1986) industrial laboratories. 

However, some of the basic problems of polypyrrole and of the other heterocyclic polymers act to limit the performance of the lithium/polymer battery, and thus its wide applicability. These are essentially slow kinetics, self-discharge and low energy content. 

Although the diffusion of the counterion is faster in polypyrrole than in polyacetylene, its value is still low enough to influence the rate of the electrochemical charge and discharge processes of lithium/polymer batteries. Indeed the current output of these batteries is generally confined to a few mA cm . Possibly, improvements in the electrode kinetics, and thus in the battery rates, may be obtained by the replacement of standard ... 

The majority of polymer electrodes cannot be doped to very high levels. For instance, polypyrrole may reach doping levels of the order of 33%. This inherent limitation combined with the fact that the operation of the lithium/polymer battery requires an excess of electrolyte (to ensure... 

The molecular orbital (MO) calculations within the PM3 method, using a MOP AC package, provided an explanation of the advantages of a new redox system, poly(l,4-phenylene-l,2,4-dithiazolium-3, 5 -yl) (PPDTA), as a cathode material for high-capacity lithium secondary batteries in comparison with three typical polymer conductors (poly-/>-phenylene, polypyrrole, and polythiophene). The MO calculation revealed that the S-S bond in the 1,2,4-dithiazo-lium moiety of PPDTA caused gap narrowing and a downshift of HOMO and LUMO levels, which is consistent with the electrochemical experiment (HOMO = highest occupied molecular orbital LUMO = lowest unoccupied molecular orbital) <2001MI2305>. 

Kuwabata S, Kishimoto A, Tanaka T, Yoneyama H. Electrochemical synthesis of composite films of manganese dioxide and polypyrrole and their properties as an active material in lithium secondary batteries. J Electrochem Soc 1994 141 10-15. 

Veeraraghavan, B., Paul, J., Haran, B., and Popov, B., Study of polypyrrole graphite composite as anode material for secondary lithium-ion batteries, J. Power Sources, 109, 377, 2002. 

A major goal of the research on conducting polymers has been the development of a rechargeable plastic battery. Cells based on polypyrrole and lithium electrodes have been developed in which the energy per unit mass and discharge characteristics are comparable to nickel-cadmium cells. Current interest appears to center around stable, processable polymers, such as polythiophene and its derivatives, and polyaniline. 

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