Metal Polymer Batteries

1 This chapter has been enhanced by attentive reviewing by Philippe Azais, a researcher at CEA-Grenoble. 

Lithium s very low electrochemical potential renders it a very powerful reducing agent. Lithium will react with any other component in its vicinity. On contact with the nitrogen in the air, it forms a layer of nitride by way of the following reaction  

Handled in as dry an environment as possible, the surface of lithium comprises a layer of oxide (and/or hydroxide in the presence of atmospheric water) and carbonate, formed by the reactions  

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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 goal for this battery is to be a substitution for the valve-regulated lead-acid battery (VRLA) as a backup power supply of for telecommunication. Usually, the relay machines of the telecommunication structure are located in remote areas. The VRLA with its short life is inconvenient from a maintenance aspect. Avestor s lithium metal polymer battery drastically reduced the load and cost of the maintenance, because the life of their battery is over 10 years and is maintenance free. Further, the feature of the battery is that the condition of the battery itself can be monitored in remote settings. 

In a lithium-metal polymer battery, the eleetrochemical chain involved is ... 

Figure 8.1. Principle of operation of the lithium-metal polymer battery...

Lithium-Metal-Polymer Batteries for Electric Auto Applications... 

In particular, in lithium metal polymer batteries, dendritic growth of lithium on a lithium anode, formation of dead lithium, interfacial phenomenon between the lithium anode and the polymer electrolyte, etc., adversely affects the stability and cycle characteristics of the batteries. In view of these problems, various polymer electrolytes have been developed. 

Avestor spent hundreds of millions of dollars to develop a lithium metal polymer battery, but the company went out of business. The battery used a low-voltage LiV30g positive to stabilize the polymer electrolyte, which consisted of a PE oxide polyether copolymer and hthium perfluorosulfonimide (Li(CF3S0CNS02CF3)). The battery was heated above 40 °C in order to achieve a conductivity of 10 S cm . The battery proved ineffective for use in electric vehicles, but showed some promise in telecommunications applications where cycling was limited. However, even the telecommunications apphcation did not work out. 

Khurana, R., Schaefer, J.L., Archer, L.A., Coates, G.W. 2014. Suppression of lithium dendrite growth using cross-linked polyethylene/poly(ethylene oxide) electrolytes A new approach for practical lithium-metal polymer batteries. T. Am. Chem. Soc. 136 7395-7402. 

Lithium-Ion Cells. Lithium-ion cells and the newer alternative, lithium-ion-polymer, can usually run much longer on a charge than comparable-size Nicad and nickel-metal hydride batteries. Usually is the keyword here since it depends on the battery s application. If the product using the battery requires low levels of sustained current, the lithium battery will perform very well however, for high-power technology, lithium cells do not perform as well as Nicad or nickel-metal hydride batteries. 

The development of a rechargeable polymer battery is being pursued worldwide. Its attraction lies in the specific weight of polymers, which is considerably lower than that of ordinary inorganic materials, as well as potential environmental benefits. In principle there are three different types of battery. The active polymer electrode can be used either as cathode (cell types 1, 2), or as anode (cell type 3), or as both cathode and anode (cell type 4) (Fig. 14). As the most common polymer materials are usually only oxidizable, recent research has concentrated on developing cells with a polymer cathode and a metal anode. 

As to anodes, in most of the research work a generously dimensioned sheet of lithium metal has been used. Such an electrode is rather irreversible, but this is not noticed when a large excess of lithium is employed. Li-Al alloys and carbon materials inserting lithium cathodically during recharging can be used as anodes in nonaqueous solutions. Zinc has been used in polymer batteries with aqueous electrolyte (on the basis of polyaniline). 

NEW CONCEPT FOR THE METAL-AIR BATTERIES USING COMPOSITES CONDUCTING POLYMERS / EXPANDED GRAPHITE AS CATALYSTS... 

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. 

Conducting polymers, polyaniline, catalytic activity, PANI/expanded graphite composites, metal-air batteries, primary rechargeable cells. 

Some theoretical prerequisites for application of modified and expanded graphites, Si- and Sn-based composites and alloys, electroconducting polymers as active materials, catalysts and electro-conductive additives for lithium - ion batteries, metal-air batteries and electrochemical capacitors are considered. The models and the main concepts of battery-related use for such materials are proposed. 

Modified graphite expanded graphite Si- and Sn- composites alloys conducting polymers lithium-ion batteries metal-air batteries electrochemical capacitors. 

V.G. Khomenko, V.Z. Barsukov, A.S. Katashinskii and T.I. Motronyuk. New concept for the metal-air batteries using composites conducting polymers/ expanded graphite. This book. 

Lithium polymer batteries are similar in principle to the lithium batteries described above but the electrolyte is a polymer. The advantage of these batteries is the absence of liquid in the cell and so the batteries do not leak. The polymer electrolyte is a polymer-alkali metal salt complex. The best known such electrolytes are complexes of poly (ethylene) oxide (PEO). 

Scale-up from laboratory test cells to EV module is the next challenge for the LPB technology. There are three general areas which need to be addressed when considering scale-up, namely (1) raw materials, (2) component fabrication, and (3) cell and battery construction. In general, the raw materials employed in the various forms of lithium polymer batteries can easily be obtained in large quantities. The key areas are the lithium metal foil and the active positive material. Lithium metal foils are commercially available in a range of thicknesses down to 50 pm. However, thinner... 

LPB (lithium polymer battery) A cell (generally rechargeable) having a lithium foil negative, a metal oxide positive and a polymer electrolyte. 

Batteries. Many 7t-conjugated polymers can be reversibly oxidized or reduced. This has led to interest in these materials for charge-storage batteries, since polymers are lightweight compared to metallic electrodes and liquid electrolytes. Research on polymer batteries has focused on the use of polymers as both the electrode and electrolyte. Typical polymer electrolytes are formed from complexes between metal-ion salts and polar polymers such as poly(ethyleneoxide). The conductivity is low at room temperature due to the low mobility of cations through the polymer-matrix, and the batteries work more efficiendy when heated above the glass-transition temperature of the polymer. Advances in the development of polymer electrolytes have included polymers poly(ethylene oxide) intercalated into layered silicates (96). These solid-phase electrolytes exhibit significantly improved conductance at room temperature. 

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