Batteries with polyacetylene

Nagatomo, T., G. Ichikawa, and O. Omoto. 1987. All-plastic batteries with polyacetylene electrodes. 7 Electrochem Soc 134 (2) 305. 

An all-plastic battery may have many advantages [26]. For example, a car battery made of polyacetylene could weigh only one-tenth of that of a conventional lead-acid battery. Moreover, batteries with plastic electrodes could be fabricated into odd shapes, such as a flat disc that could be slotted into a car door. Prototype batteries have been made using polyacetylene and poly-p-phenylene electrodes, but a number of technical problems, such as long-term mechanical integrity need to be solved. 

Nagatomo, T., et aL 1983. A long-lasting polyacetylene battery with high energy density. Jpn J Appl Phys 22 L275. 

Battery designs using electroactive polymers feature the EAP as the cathode, which is separated from an anode (such as Li, Na, Mg, and Zn) by an electrolyte. Normally, high specific energies of up to 3.5 V can be obtained (409). EAPs that have been used in rechargeable batteries include polyacetylene-, PANI-, PPy-, PT-, and PPP-based materials (410). The current drawback to full utilization of EAPs for rechargeable batteries is the rate limitations associated with low ionic mobilities of the polymers as well as the electrolytes (14). 

More recently, an all-polymer battery based on derivatized polythiophenes supported on graphite-coated supports was described (139). In this instance, polythiophene functioned more effectively in the n-doping region and provided an improved cell discharge voltage of 2.4 V and capacities of 9.5-1.5 mAh g. A recent approach is the development of a polymer/polsrmer battery based on polyaniline anode and poly-l-naphthol cathode (140). This device has been reported with an impressive cell voltage of 1.4 V, a specific capacity of 150 Ah g, and a loss of 15% of cell capacity after 100 cycles. Other attempts at fabricating battery systems have been made (141) with polyacetylene, polypyrrole, and polyanibne (142),... 

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. 

Polyacetylene proved qnite incapable of working in a realistic battery context, and MacDiarmid did not mention this application in his Nobel lectnre of October, 8 2000. However, other materials have proven their worth, and prototype batteries made with polypyrrole and polyaniline as cathodes (positives), and metal or lithiated carbon materials as anodes (negatives), have been demonstrated in dne conrse by the Japanese and German indnstry, for instance. Novdk et al. (1997) have reviewed the field in detail. 

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. 

Most photoeonductive polymers can be used in solar batteries. The high resistivity of the polymers decreases the actual power of the devices. Possibilities may be connected with electron-donor doping of the polymers. As stated earlier some success has been achieved in this field for polyacetylenes and other conjugated polymers. 

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