Batteries with conducting polymers

Besides the conductive additive, TEG may sometimes be a very effective catalyst support, for example, in the catalytic active composite with conducting polymers for the new air-metal batteries, which we proposed [6],... 

In this chapter, lithium secondary batteries using conductive polymers as positive electrodes are discussed with particular attention to the charge-discharge characteristics, discharge capacity, self-discharge, cycling life and so on. 

Fukami K, Sakka T, Ogata YH, Yamauchi T, TsubokawaN (2009) Multistep filling of porous silicon with conductive polymer by electropolymerization. Physica Status Solidi (a) 206 1259 Gao L, Mbonu N, Cao L, Gao D (2008) Label-lfee colorimetric detection of gelatinases on nanoporous silicon photonic films. Anal Chem 80 1468 Ge M, Rong J, Fang X, Zhou C (2012) Porous doped sdicon nanowires for lithium ion battery anode with long cycle life. Nano Lett 12 2318... 

The active polymeric electrode can be either the anode or the cathode of the cell. Battery cells with conducting polymers as the anode are most common due to difficulties in inserting negative charges into polyheterocycles. 

With growing experience of these materials, a number of more realistic applications have now emerged that tend to exploit the novel features associated with conductive polymers rather than those properties that are readily obtainable in more traditional materials. Some of these applications include plastic batteries, sensors, electrochromic displays, EMI shielding, fuel cells and various biomedical devices, and these are now discussed. 

This distribution causes a problem the best-described conducting polymers interchange anions with the electrolyte, and the Li electrode liberates Li+during discharge. The salt accumulates in the electrolyte [Fig. 32(a)], requiring a great volume and mass in order to avoid the precipitation of the salt. This fact reduces the specific energy of the battery to impractical values. 

In battery applications, new hthium ion batteries called lithium ion polymer batteries (or more simply but misleadingly, lithium polymer batteries) work with a full matrix of ionically conducting polymer, this polymer being present inside the porous electrodes and as a separator between the electrodes. They are offered in attractive flat shapes for mobile applications (mobile phones, notebooks). 

The concept of electrochemical intercalation/insertion of guest ions into the host material is further used in connection with redox processes in electronically conductive polymers (polyacetylene, polypyrrole, etc., see below). The product of the electrochemical insertion reaction should also be an electrical conductor. The latter condition is sometimes by-passed, in systems where the non-conducting host material (e.g. fluorographite) is finely mixed with a conductive binder. All the mentioned host materials (graphite, oxides, sulphides, polymers, fluorographite) are studied as prospective cathodic materials for Li batteries. 

Nitration of the surface of polypyrrole and the subsequent reduction of the nitrate groups has been reported [244] and Bidan et al. [306, 307] have investigated the electrochemistry of a number of polymers based on pyrroles with /V-substituents which are themselves electrochemically active. Polypyrrole has also been successfully deposited onto polymeric films of ruthenium complexes [387], and has been used as an electrode for the deposition and stripping of mercury [388], As with most conducting polymers, several papers have also appeared on the use of polypyrrole in battery systems (e.g. [327, 389] and Ref. therein). 

The mechanisms and reasons of catalytic activity of polyaniline (PANI)-type conducting polymers toward oxygen reduction in acidic and saline solutions are investigated by electrochemical and quantum-chemical methods. The PANI/thermally expanded graphite compositions were developed for realization of fully functional air gas-diffusion electrodes. Principally new concept for creation of rechargeable metal-air batteries with such type of catalysts is proposed. The mockups of primary and rechargeable metal-air batteries with new type of polymer composite catalysts were developed and tested. 

The future remains bright for the use of carbon materials in batteries. In the past several years, several new carbon materials have appeared mesophase pitch fibers, expanded graphite and carbon nanotubes. New electrolyte additives for Li-Ion permit the use of low cost PC based electrolytes with natural graphite anodes. Carbon nanotubes are attractive new materials and it appears that they will be available in quantity in the near future. They have a high ratio of the base plane to edge plain found in HOPG. The ultracapacitor application to deposit an electronically conductive polymer on the surface of a carbon nanotube may be the wave of the future. 

Lithium iodide is the electrolyte in a number of specialist batteries, especially in implanted cardiac pacemakers. In this battery the anode is made of lithium metal. A conducting polymer of iodine and poly-2-vinyl pyridine (P2VP) is employed as cathode because iodine itself is not a good enough electronic conductor (Fig. 2.3a). The cell is fabricated by placing the Li anode in contact with the polyvinyl pyridine-iodine polymer. The lithium, being a reactive metal, immediately combines with the iodine in the polymer to form a thin layer of lithium iodide, Lil, which acts as the electrolyte ... 

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