Polymer Batteries for Electronics

Most of the lithium-ion battery and supercapacitor research and development projects are focused on the fabrication of prototypes using liquid electrolytes. An important step forward in this technology is the replacement of the liquid electrolyte with an ionic membrane and, eventually, of the common inorganic-type electrode materials with advanced electronically conducting polymers, in order to produce novel devices having a full polymeric configuration. This is an interesting concept since it provides the prospect of a favourable combination of 

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Volume 10 includes topics on organic and polymer-based light emitting diodes, optical devices based on conducting polymers, intercalation compounds for advanced lithium batteries, polymer electrets for electronics, sensor, and photonic applications, charge transporting polymers and molecular glasses, and electrochemically prepared thin films for solar cells. 

Another limiting factor is that it may not be possible to use some of these electronically conducting organic compounds in aqueous solutions. This is true of the polymer most used in new polymer batteries, polyacetylene, for which an appropriate solvent is propylene carbonate (see Fig. 4.115). 

The substitution of the liquid electrolyte with the less reactive polymer electrolyte has led to lithium-polymer batteries, among the most likely to be commercialized for electric vehicles [89]. It must be stressed that the lithium-polymer battery is still a lithium-metal battery and not a lithium-ion one. Lithium-polymer batteries are solid-state, in that their electrolyte is a solid. A great safety advantage of this type of battery is that the electrolyte will not leak out if there is a rupture in the battery case. Furthermore, it can be assembled in any size and shape, allowing manufacturers considerable flexibility in cell design for electric vehicle or electronic equipment. 

Major polymer applications housings for electronic and electrical plications, instrument lenses packaging for higli barrier properties, bottles, appliances (housings, air conditioner parts, refrigerator shelves, blenders, lenses), house-wares (eating utensils, beverage/food containers, display boxes), automotive (dashboard, battery cases)... 

This type of Li battery has already widely diffused in the electronic consumer market, however for automotive applications the presence of a liquid electrolyte is not considered the best solution in terms of safety, then for this type of utilization the so-called lithium polymer batteries appear more convenient. They are based on a polymeric electrolyte which permits the transfer of lithium ions between the electrodes [21]. The anode can be composed either of a lithium metal foil (in this case the device is known as lithium metal polymer battery) or of lithium supported on carbon (lithium ion polymer battery), while the cathode is constituted by an oxide of lithium and other metals, of the same type used in lithium-ion batteries, in which the lithium reversible intercalation can occur. For lithium metal polymer batteries the overall cycling process involves the lithium stripping-deposition at the anode, and the deintercalation-intercalation at the anode, according to the following electrochemical reaction, written for a Mn-based cathode ... 

The lithium-polymer version of these batteries is another area where work is needed. Lithium-polymer batteries are being rapidly developed for portable consumer electronics applications and may be used in the future for EV/HEVs since the polymer design mitigates safety concerns regarding lithium metal in large cells. Some work to develop recycling processes is under way, but no details have been published and no process test data have been made available. Although many of the constituents are shared in common with the Li-ion battery system, the presence of a solid polymer... 

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