Cathode material activation

The use of 1,3-propane sultone in an ethylene carbonate dimethyl carbonate electrolyte with LiP04 as a protective additive has been assessed during cathode material activation and cycling at a high potential (89). 

Reserve batteries have been developed for appHcations that require a long inactive shelf period foUowed by intense discharge during which high energy and power, and sometimes operation at low ambient temperature, are required. These batteries are usually classified by the mechanism of activation which is employed. There are water-activated batteries that utilize fresh or seawater electrolyte-activated batteries, some using the complete electrolyte, some only the solvent gas-activated batteries where the gas is used as either an active cathode material or part of the electrolyte and heat-activated or thermal batteries which use a soHd salt electrolyte activated by melting on appHcation of heat. 

Mild steel cathodes are used extensively in chlor-alkah and chlorate cells. Newer activated cathode materials have been developed that decrease cell voltages about 0.2 V below that for cells having mild steel cathodes. Some activated cathodes have operated in production membrane cells for three years with only minor increases in voltage (17). Activated cathodes can decrease the energy consumption for chlorine—caustic production by 5 to 6.5%. 

Although it is important that no water should exist in the cathode materials of nonaqueous batteries, the presence of a little water is unavoidable when Mn02 is used as the active material. It is believed that this water is bound in the crystal structure, and that it has no effect on the storage characteristics, as shown in Fig. 27, where the relationship of the MnO,... 

Nevertheless, water is decomposed with evolution of hydrogen but under controlled conditions and with a reasonable reaction rate. With water as the active cathode material, the battery system—used in military underwater applications—can be designed as (-) Li / KOH / H20 (+) [19]. The... 

Masset P, Guidotti RA (2008) Thermal activated ( thermal ) battery technology Part Ilia FeS2 cathode material. J Power Sources 177 595-609... 

Solid alkaline membrane fuel cells (SAMECs) can be a good alternative to PEMFCs. The activation of the oxidation of alcohols and reduction of oxygen occurring in fuel cells is easier in alkaline media than in acid media [Wang et al., 2003 Yang, 2004]. Therefore, less Pt or even non-noble metals can be used owing to the improved electrode kinetics. Eor example, Ag/C catalytic powder can be used as an efficient cathode material [Demarconnay et al., 2004 Lamy et al., 2006]. It has also... 

The electrochemical behavior of thin-film oxide-hydroxide electrodes containing chromium, nickel and cobalt compounds was investigated. Experimental results have shown that such compounds can be successfully used as active cathodic materials in a number of emerging primary and secondary battery applications. 

Thin-film electrodes have promise in the development of flexible power sources (primary and secondary). It must be taken into account that change in cathodic material crystal lattice must not be over 20% as a result of intercalation of Li+, Na+ or FT [4], The electrodes must be chemically active and have both electron and ion conductivity. In connection with these... 

It is shown that the first step in the electrochemical reduction of cathodic material CoxOy(OH)z in power sources is controlled by kinetics. This process at the interface depends on the catalytic activity of compound, Figure 7 (a) the reduction of the bulk of cathodic materials is controlled by diffusion Figure 7 (b). 

In this chapter the technological development in cathode materials, particularly the advances being made in the material s composition, fabrication, microstructure optimization, electrocatalytic activity, and stability of perovskite-based cathodes will be reviewed. The emphasis will be on the defect structure, conductivity, thermal expansion coefficient, and electrocatalytic activity of the extensively studied man-ganite-, cobaltite-, and ferrite-based perovskites. Alterative mixed ionic and electronic conducting perovskite-related oxides are discussed in relation to their potential application as cathodes for ITSOFCs. The interfacial reaction and compatibility of the perovskite-based cathode materials with electrolyte and metallic interconnect is also examined. Finally the degradation and performance stability of cathodes under SOFC operating conditions are described. 

To develop an alternative MIEC cathode not only the ex situ properties, e.g., cr, TEC, /), and k, but also the electrocatalytic activity, structural and chemical stability, and Cr-tolerance must be considered. Beyond testing in small SOFC button cells, the viability of new cathode materials must ultimately be proven in large-scale stack cells under practical current and temperature gradients. The issues involved in the development of cathode materials for large-scale stacks are significantly more complex than those in the small button cells briefly reviewed in this chapter. However, this does provide serious challenges as well as opportunities for materials scientists and engineers in the development of commercially viable ITSOFCs. 

Research on cathode materials focuses on reduction of the high chemical activity of the lower WF metals (e.g., Ca/Al), the increase of the chemical stability, and improvement of the sticking coefficient of the interlayer materials (e.g., LiF/Al). 

After the description of chemical structure and control of meso-architecture and surface area, selected applications of such carbon materials as battery electrodes, supercapacitors, and in the design of controlled hybrid heterojunctions were presented. In the Li battery, coating or hybridization with hydrothermal carbon brought excellent capacities at simultaneous excellent stabilities and rate performances. This was exemplified by hybridization with Si, Sn02 (both anode materials) as well as LiFeP04 (a cathode material). In the design of supercapacitors, porous HTC carbons could easily reach the benchmark of optimized activated traditional carbons, with better stability and rate performance. 

---