Polyaniline lithium battery 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 carbazole polymer poly(iV-vinylcarbazole) functions as a positive electrode material for a secondary lithium battery <85CC553>, and as a memory photoreceptor <91M1 204-0l>. The related poly[3-(3-bromocarbazol-9-yl)propyl]methylsiloxane (18) forms novel electrochromic films <89CC196>. Carbazole anions have b n used to initiate the polymerization of acrylates and methacrylates <95CC275>. The novel polymeric pyrrolocarbazole (19) displays physical properties similar to those of polyanilines. 

Oyama, N., Tktsuma, T., Sato, T., Sotomura, X, 1995. Dimercaptan-polyaniline composite electrodes for lithium batteries with high energy density. Nature 373,598-600. 

For the synthesis of polyaniline designed for battery electrodes, Fe(C104)3 and Cu(BF4)2 are preferable as oxidizing agents, because the products contain CIO 4 or BFi anions, which are commonly used in lithium secondary batteries. Polyaniline synthesized by Cu(Bp4)2 has a fibrous morphology [57],... 

The use of polyaniline as a possible electrode in a rechargeable solid-state battery appears promising and was first investigated by DeSurville et al. [178]. Both aqueous [179,180] and nonaqueous cells have been extensively investigated [181-183]. A lithium/polyaniline rechargeable battery is now commercially available from Bridgestone and Seiko Electronics in Japan. 

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). 

ZnO displays similar redox and alloying chemistry to the tin oxides on Li insertion [353]. Therefore, it may be an interesting network modifier for tin oxides. Also, ZnSnOs was proposed as a new anode material for lithium-ion batteries [354]. It was prepared as the amorphous product by pyrolysis of ZnSn(OH)6. The reversible capacity of the ZnSn03 electrode was found to be more than 0.8 Ah/g. Zhao and Cao [356] studied antimony-zinc alloy as a potential material for such batteries. Also, zinc-graphite composite was investigated [357] as a candidate for an electrode in lithium-ion batteries. Zinc parhcles were deposited mainly onto graphite surfaces. Also, zinc-polyaniline batteries were developed [358]. The authors examined the parameters that affect the life cycle of such batteries. They found that Zn passivahon is the main factor of the life cycle of zinc-polyaniline batteries. In recent times [359], zinc-poly(anihne-co-o-aminophenol) rechargeable battery was also studied. Other types of batteries based on zinc were of some interest [360]. 

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. 

A battery cell where both the electrodes consist of dopable polymer is shown in Figure 5.23. The electrolyte in this case consists of Li+ClO 4 dissolved in an inert organic solvent, usually tetrahydro-furan or propylene carbonate. When two sheets of polyacetylene or PPP are separated by an insulating film of polycarbonate saturated in an electrolyte (lithium perchlorate), and completely encapsulated in a plastic casing, a plastic battery can be made. The two sheets of polyacetylene or PPP act as both anode and cathode for the battery. A schematic is shown in Figure 5.24. Although doped polyacetylene and polyaniline electrodes have been developed, polypyrrole-salt films are the most promising for practical appKcation. 

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