Materials for Batteries

Practically every battery system uses carbon in one form or another. The purity, morphology and physical form are very important factors in its effective use in all these applications. Its use in lithium-ion batteries (Li-Ion), fuel cells and other battery systems has been reviewed previously [1 -8]. Two recent applications in alkaline cells and Li-Ion cells will be discussed in more detail. Table 1 contains a partial listing of the use of carbon materials in batteries that stretch across a wide spectrum of battery technologies and materials. Materials stretch from bituminous materials used to seal carbon-zinc and lead acid batteries to synthetic graphites used as active materials in lithium ion cells. 

Carbon-Zinc Sealant, cathode conductive carbon black matrix 

Alkaline Zn-MnCh Sealant, cathode conductive graphite matrix 

Zinc-Air Sealant, cathode catalyst support and current collector 

Li-Ion Anode active mass, cathode conductive diluent 

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Transition-metal oxides and their mixtures are widely employed in numerous industrial applications, especially as cathode materials for batteries and fuel cells [1,2], Practice poses certain well-known requirements to oxide materials, first of all, to uniformity of the size distribution of particles, to homogeneity of mixed oxides, etc. To meet these demands, two broad categories of methods are now in use, vs (i) mechanical methods and (ii) chemical methods. 

In large volume production, the availability of electrode materials for batteries must also be considered, such as cobalt, nickel, iron or manganese, and above all lithium (see also Deutsche Bank, 2008). The lithium demand is 0.3 kg lithium metal equivalent/kWh (Tahil, 2006) 17 for a 30 kWh battery (20 kWh/100 km and 150 km range) this results in 9 kg lithium/vehicle. To avoid stresses on lithium supply battery recycling will be crucial. 

This chapter deals with the potential and perspective of CNT-based carbon and inorganic hybrid materials for battery and capacitor applications. 

Dr. Hui has worked on various projects, including chemical sensors, solid oxide fuel cells, magnetic materials, gas separation membranes, nanostruc-tured materials, thin film fabrication, and protective coatings for metals. He has more than 80 research publications, one worldwide patent, and one U.S. patent (pending). He is currently leading and involved in several projects for the development of metal-supported solid oxide fuel cells (SOFCs), ceramic nanomaterials as catalyst supports for high-temperature PEM fuel cells, protective ceramic coatings on metallic substrates, ceramic electrode materials for batteries, and ceramic proton conductors. Dr. Hui is also an active member of the Electrochemical Society and the American Ceramic Society. 

Doughty, D.H.. H. Brack, K, Naoi, and L.F. Nazar New Materials for Batteries ami Fuel CeU,, Materials Research Society. Warrendale. PA. 2000. 

Danilov M.O., Melezhyk A.V. Carbon nano-structures as hydrogen-adsorbing materials for battery anodes. Russian J. of Applied Chemistry, 2004, 77(12), 1980-1984. 

Mizushima K, Jones PC, Wiseman PJ, Goodenough JB. LixCo02 (0cathode material for batteries of high energy density. Mater Res Bull. 1980 15(6) 783-9. 

Refs. [i] http /lwww.seca.doe.gov [ii] http //www.spice.or.jp/ fisher/ sofc.html descript [iii] http //www.pg.siemens.com/en/fuelcells/sofc/ tubular/index.cfm [iv] Weissbart J, Ruka R (1962) J Electrochem Soc 109 723 [v] Park S, Vohs JM, Gorte RJ (2000) Nature 404 265 [vi] Liou J, Liou P, Sheu T (1999) Physical properties and crystal chemistry of bismuth oxide solid solution. In Processing and characterization of electrochemical materials and devices. Proc Symp Ceram Trans 109, Indianapolis, pp 3-10 [vii] Singhal SC (2000) MRS Bull 25 16 [viii] Matsuzaki Y, Yasuda I (2001) J Electrochem Soc 148 A126 [ix] Ralph JM, Kilner JA, Steele BCH (1999) Improving Gd-doped ceria electrolytes for low temperature solid oxide fuel cells. In New Materials for batteries and fuel cells. Proc Symp San Francisco, pp 309-314... 

Ohzuku, T., and Ueda, A., Why transition metal (di)oxides are the most attractive materials for batteries. Solid State Ionics, 69, 201, 1994. 

Volume 575— Hew Materials for Batteries and Fuel Cells, D.H. Doughty, H-P. Brack, R. Haoi,... 

PPP [5] (cf. below). The highly conducting PA found by Naannann in 1987 [285, 286] could not make up for this disadvantage. Such a high conductivity is not at all necessary for battery applications. The rate of electrochemical doping/undoping (anions) is rather low due to the extremely small diffusion coefficient in the fabrils [287]. Today, the earlier interest in this material for batteries has totally disappeared. 

A number of metal oxides can be described as porous materials. For instance, porous manganese oxides define octahedral molecular sieves (OMS) that have been introduced in recent years as possible materials for batteries, separations, and chemical... 

Li metal is attractive as an anode material for batteries as it is the most electronegative metal (-3.04 V vs. SHE) that benefits the high cell voltage, as well as the lightest (equivalent weight M=46.94 g moL, and density p=40.53 gcm" ) which facilitates the design of hghter and smaller batteries. 

Lithium and sulfur are promising active electrode materials for batteries because of their low equivalent weight, low cost, and suitable electrochemical properties. The major question in the use of these active electrode materials is whether the electrodes will be able to provide sustained high performance. Until recently, capacity retention over an extended period has been difficult to achieve. 

When PANI is used as a material for batteries, a very acid solution is used in which it can be cycled during a very long time between leucoemeraldine and green ES. As already stated, for electrochromic devices it is necessary to have a coloured form as blue as possible . It is necessary to seek for the pH value which allows a compromise between an interesting colour and a good reversibility associated with a weak degradation. Results obtained at pH = 0 (HCI IM-(-KCI IM), pH=l (HCI O.IM-I-KCI IM), pHn=3 (HCI O.OOlM-EKCI IM) and pH = 4.6 (acetic buffer) are compared. 

These examples show clearly that microwave heating can be used to produce novel materials for battery precursors. The capacity of these materials and their degradation during cycling need to be maximized and stabilized, respectively. In most cases, stability and enhanced capacity depend on several other parameters in the tested battery composite such as the inclusion of additives such as carbon to increase conductivity, the size and morphologies of the components, as well as the porosity of the materials. Given the rapid reaction rates possible and the ease with which parameters can be varied, microwave heating proves to be a very versatile approach to the research and development of new battery materials. 

Lithium has a number of advantages over other materials for battery manufacture. It is the lightest tme metal, and it also has a high electrochemical reduction potential, that is, it occurs at the bottom of Table 9.1. There is one disadvantage in using lithium in that it is very reactive, a feature that poses problems not only in manufacture but also in the selection of the other battery components. Despite this, there are a large number of lithium-based primary cells available, both in traditional cylindrical form and as button and flat coin cells. 

Obviously, special attention should be paid to the content of contaminants (impurities) from the first two categories in the source materials for battery manufacture (lead, lead alloys, H2SO4, expander, etc.). Impurities in these materials should be kept below definite maximum allowable limits so as to prevent them to influence the gassing rate in the cells. The maximum allowable concentrations of contaminants (impurities) in the sulfuric acid electrolyte according to the data reported in Ref. [51] are as follows ... 

Mermilliod, N., Tanguy, J., Petiot, E, 1986. A study of chemically synthesized polypyrrole as electrode material for battery applications. J. Electrochem. Soc. 133,1073-1079. 

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