Daniel, battery

VASP is also able to simulate the Daniell battery [106]. The model is a bimetallic slab consisting of two parts in epitaxy, one made of copper and the other of zinc. The interspace between the successive slabs is filled by four layers of water, originally in a hexagonal ice arrangement, and the optimization is run. One layer of water decomposes, the OH being adsorbed on Cu and the ff" on the Zn. There is a relaxation of the metal surfaces at the interfaces, some Zn atoms moving significantly outward. A limited periodic model accounts then for a typical electrochemical reaction. 

The challenge of acid-alkaline hybrid power sources lies in how to separate the acid and alkaline electrolytes effectively while maintaining ion transport between these two electrolytes. As shown in Table 11.1, some conventional electrochemical power sources do operate in two chambers with two electrolytes separated by a membrane or an ionic interface, such as the Daniell cell and most flow batteries. In these well-known electrochemical cells with two electrolytes, the pEt value of both anolyte and catholyte are almost the same and there usually exists a common species to function as a charge carrier between the anolyte and catholyte. Examples include S04 ion for Daniell battery, and H+ ion for vanadium redox flow battery, in which there is a separator to avoid electrolyte mixing. An ion-exchange... 

K. Kordesch, J. Daniel-Ivad, Ch. Faistauer, High power rechargeable alkaline manganese dioxide-zinc batteries, 182nd Meeting of the Electrochem. Soc., Toronto, Oct., 1992, Extended Abstract 92-2, p. 18-18 (6 AA-bundle battery replacement of single D-cell). 

K. Kordesch, C. Faistauer, J. Daniel-Ivad, RAM batteries for consumer applications and the proper selection of chargers, IBA, 8th Int. Battery Symp., Brussels, May 1993 Prog. Batteries Batt. Mater., 1994, 13, 88-213. 

K. Kordesch, J. Daniel-Ivad, Rechargeable manganese dioxide batteries (recent chargers), Proc. 37th Power Sources Conf, Cherry Hill, NJ, June 17-20, 1996, pp. 436-439 K. Kordesch, C. Faistauer, D. Zhang (Patent Pending). 

J. Daniel-Ivad, K. Kordesch, In-application use of rechargeable alkaline manganese diox-ide/zinc RAM batteries, Portable by Design Conference, Santa Clara, CA, March 24-27, 1997... 

One of the first batteries in recent times was the Daniell cell,... 

Figure 1. Representation of a battery (Daniell cell) showing the key features of battery operation and the requirements on electron and ion conduction.

The Daniell cell illustrates the basic features of an electrochemical cell. Electrochemical cells always involve a redox reaction. Oxidation occurs at the cathode of the cell and reduction takes place at the anode. Electrons always flow from the anode to the cathode. Electrochemical cells come in many arrangements. To gain an appreciation for the variety of electrochemical cells, consider all the types of batteries available. 

It is immediately apparent that the Daniell cell differs from the zinc-chlorine battery in that the electrode materials (i.e., zinc and copper) of the former are both metals that normally exhibit a tendency to lose electrons. If the Daniell cell is to function as a battery, both metals cannot lose electrons—one must lose and the other must gain electrons. In this particular case, the issue can be decided, qualitatively at least, in terms of the order of activity of the metals. From Table 11.1, it should be recalled that zinc is much more active chemically than copper hence zinc might be expected to lose electrons more readily than copper if the metals are in contact with solutions of their ions at the same concentration. It may be inferred correctly that the reactions that occur when the Daniell cell serves as a source of electrical energy are as follows ... 

In terms of the data of Table 11.2, the voltage produced by the Daniell cell is seen to be the sum of the negative potential of the zinc electrode and the positive potential of the copper electrode (i.e., 0.758 + 0.344 = 1.102 V). The voltage produced by a battery involving a cadmium and a lead electrode would be the difference between the two potentials (i.e., 0.397 - 0.12 = 0.277 V), since both of these electrodes are negative with respect to solutions of their ions. 

Any consideration of the requirements to be fulfilled in the construction of battery cells should recognize first that the substances used as electrodes may be, but need not be, produced by electrolysis. In the earlier discussion of the zinc-chlorine battery, both of the substances involved at the two terminals were considered to be the products of a previously conducted electrolysis. However, the zinc-chlorine battery could just as well have been constructed by the use of zinc and chlorine produced by entirely nonelectrolytic methods. You should recall that, in connection with the description of the Daniell cell, no specifications were made with regard to the origin of any of the chemicals involved. This freedom to select suitable materials regardless of their origin or past history follows from the fact that the changes that occur during... 

A battery requires two half cells, each of which must involve two oxidation states of an element. Thus, in the Daniell cell, one of the half cells consists of copper metal (oxidation number = 0) in contact with... 

John Daniell (English physicist) developed the first modern storage cell based on Faraday s principles. This consists of a large glass jar with a copper star-shaped electrode in the bottom and a zinc "crow s foot" shaped electrode suspended near the top. The bottom of the jar was filled with a concentrated copper sulfate solution. On top of this was poured dilute sulfuric acid, whose lower density kept it on top. This was the first practical battery to find wide use to power telegraphs and railway signaling systems and home doorbells. 

Electrochemical energy storage and conversion systems described in this chapter comprise batteries and fuel cells [6-11], In both systems, the energy-supplying processes occur at the phase boundary of the electrode-electrolyte interface moreover, the electron and ion transports are separate [6,8], Figures 8.1 and 8.2 schematically illustrate the electron and ion conductions in both the electrodes and the electrolyte in Daniel and fuel cells. The production of electrical energy by the conversion of chemical energy by means of an oxidation reaction at the anode and a reduction reaction at the cathode is also described. 

Blood.1—The defibrinated blood of a dog was submitted to electrolysis by Becquerel. He made use of platinum electrodes and a current furnished by a battery of three Daniell cells. At the negative pole he observed the following phenomena ... 

See also - chromic acid battery, - Daniell cell, -r zinc, -r Zn2+/Zn electrodes, - Zn2+/Zn(Hg) electrodes, -r zinc-air batteries (cell), and - Leclanche cell. 

Camacho cell — This was a - chromic acid battery with zinc anodes, and a construction that the chromic acid solutions flowed through the cathode compartment housing the inert carbon electrodes. See also - Daniell cell, - zinc, - Zn2+/Zn electrodes, - Zn2+/Zn(Hg) electrodes, - zinc-air batteries (cell), and - Leclanche cell. Ref [i] Hauck WP (1883) Die Galvanischen Batterien, Accumulatoren und Thermosaulen, 2nd edn. Hartleben s Verlag Wien... 

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