Aqueous batteries

The rechargeable lithium-ion battery is one of a number of new battery technologies which have been developed in the last ten years. TTiis battery system, operating at room temperature, offers several advantages compared to conventional aqueous battery technologies, for example,... 

G. H. Newmann, Proc. Workshop on Lithium Non-Aqueous Battery Electrochemistry, Publication 80-7, The Electrochemical Society, NJ, 1980, p. 143. 

Cj. In this section, the discussion will focus on graphites and amorphous carbons which are practical materials for use in aqueous batteries. 

Several significant electrode potentials of interest in aqueous batteries are listed in Table 2 these include the oxidation of carbon, and oxygen evolution/reduction reactions in acid and alkaline electrolytes. For example, for the oxidation of carbon in alkaline electrolyte, E° at 25 °C is -0.780 V vs. SHE or -0.682 V (vs. Hg/HgO reference electrode) in 0.1 molL IC0 2 at pH [14]. Based on the standard potentials for carbon in aqueous electrolytes, it is thermodynamically stable in water and other aqueous solutions at a pH less than about 13, provided no oxidizing agents are present. 

Composite structures that consist of carbon particles and a polymer or plastic material are useful for bipolar separators or electrode substrates in aqueous batteries. These structures must be impermeable to the electrolyte and electrochemical reactants or products. Furthermore, they must have acceptable electronic conductivity and mechanical properties. The physicochemical properties of carbon blacks, which are commonly used, have a major effect on the desirable properties of the conductive composite structures. Physicochemical properties such as the surface... 

A comprehensive review which discusses the surface properties and their role in the electrochemistry of carbon surfaces was written by Leon and Radovic [26]. This review provides a useful complement to the following discussion on the role of carbon in aqueous batteries. Four key parameters that are important for carbonaceous materials in batteries, which were identified by Fischer and Wissler [24], are ... 

C without serious degradation, where nonaqueous and aqueous batteries have difficulties. 

The aqueous batteries use water based electrolytes (e.g., KOH electrolyte for NiCd and NiMH and H2-SO4 electrolyte for lead acid), which are less resistive then nonaqueous electrolytes. Polyolefin materials are generally suitable for use in the manufacture of separators for these batteries, but they are not inherently wettable by aqueous electrolytes. Such electrolytes are therefore unable to penetrate the pores of a separator formed from such a material, so that ion migration through the pores in solution will not occur without modification. This problem is sometimes overcome by treating the polyolefin material with a surfactant, which allows an aqueous electrolyte to wet the material. However, such surfactant can be removed from the surfaces of the polyolefin material when electrolyte is lost from the device, for example during charging and discharging cycles, and it is not subsequently replaced on the material when the electrolyte is replenished. 

This subsequent section discusses different types of aqueous batteries and the separators used in those batteries. The recent work in the development of new separators for aqueous batteries will also be discussed in detail. 

Prospects for TR Electrolyte SBs. In view of the harmful effects often cited in the literature of even small traces of water on the operation of non-aqueous batteries with alkali metal anodes, it might be supposed that electrolytes of the TR composition cannot be applied in such batteries. This same idea may dominate when molten salt SBs are considered. Such a general conclusion cannot be justified. A dilute solution of water in a salt has the structure either of this salt proper or its adjacent hydrate, and the energy, properties and reactions of this water are quite different from those of pure water or of dilute solutions of various compounds in it. On the other hand, a small amount of water in the electrolyte system will decrease its melting point and increase its conductivity. Mixtures of water with such liquids as some alcohols or dioxane and other aprotic and even proton-forming substances, may open new prospects for... 

The reaction of lithium with the electrolyte to form a surface film significantly modifies its behaviour. On the one hand, the film confers chemical stability and useful shelf life on the system. On the other, it is responsible for greatly depressed exchange currents and the consequent phenomenon of voltage delay, as discussed in Chapter 3 in connection with magnesium aqueous batteries. It is convenient to discuss separately film formation with insoluble and with liquid and soluble cathode systems. 

Lithium Non-aqueous Battery Electrochemistry, 1980. (Ed. E. Yeager, B. Schumm, G. Blomgren, D. Blankenship, V. Leger and J. Akridge.)... 

Bennett, P.D, and S. Gross Aqueous Batteries, The Electrochemical Society. Inc, Pennington. NJ, 1997. 

A major effort continues around the world to develop high energy, long cycle life rechargeable batteries for EV applications. Not only nonaqueous batteries, but many aqueous battery and fuel cell ideas are in development, often in the form of hybrid EV concepts, i.e., in conjunction with reduced size internal combustion engines. 

Hydrous oxides are of major interest in many areas of technology, e.g., corrosion and passivation of metals, formation of decorative, protective, and insulating films, aqueous battery systems, catalysis and electrocatalysis, electrochromic display systems, pH monitoring devices, soil science, colloid chemistry, and various branches of material science. Detailed accounts of some of the nonnoble hydrous metal oxide systems, especially aluminum,1 have appeared recently. In the case of the noble metals such as platinum or gold most of the electrochemical work to date has been concerned with compact monolayer, and submonolayer, oxide growth. 

In view of their major application in aqueous battery systems more work has been carried out on the structural aspects of the oxides of these two metals than any of the systems discussed earlier. Details of the structure and reactivity of the nickel oxide battery materials can be found in recent reviews by Briggs209 and Oliva et al.2 Both hydrous and anhydrous phases exist for both the Ni(II) hydroxide and Ni(III) oxyhydroxide systems. Most interesting are the comments of Le Bihan and Figlarz,210 and McEwen,211 with regard to turbostatic structures the latter are found in materials where the ordering of the oxide is quite limited, i.e., the systems consist of highly ordered nuclei linked in a disordered manner—the latter feature should certainly enhance mass transfer processes and may well be involved in many other hydrous oxide systems. 

H. S. Lee, X.-Q. Yang, J. McBreen, Int. Patent WO 2011/031401 A2, 2011. Lithium non-fluorinated and fluorinated phenyl tiifluoro borate salts for non-aqueous battery electrolytes. 

Shanmukaraj, D. Grugeon, S. Gachot, G. LarueUe, S. Mathiron, D. Tarascon, J.-M. Armand, M., Boron esters as tunable anion carriers for non-aqueous batteries electrochemistry, J. Am. Chem. Soc. 2010,132,3055-3062. 

Peled, E., The electrochemical behavior of tilkali and alkaline earth metals in non-aqueous battery systems-The solid electrolyte interphase model, J. Electrochem. Soc., 1979,126 (12), 2047-2051. 

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