Zinc copper oxide battery

Other cells, based on zinc anodes or on mercuric oxide cathodes are known. Among them are the silver-zinc battery, zinc-copper oxide battery, mercury-cadmium battery etc. 

There are many methods of fabricating the electrodes for these cell systems. The earliest commercially successful developments used nickel hydroxide [12054-48-7], Ni(OH)2, positive electrodes. These electrodes are commonly called nickel electrodes, disregarding the actual chemical composition. Alkaline cells using the copper oxide—zinc couple preceeded nickel batteries but the CuO system never functioned well as a secondary battery. It was, however, commercially available for many years as a primary battery (see Batteries-PRIMARY cells). 

The Leclanche cell, with zinc, and manganese dioxide as depolariser, in ammonium chloride solution, described in 1868, is the precursor of the modern dry battery Lalande used zinc, and copper oxide as depolariser, in 30-40 per cent caustic potash or soda solution. ... 

Redox Reactions. For many electrochemists the paramount concern of their discipline is the reduction and oxidation (redox) reaction that occurs in electrochemical cells, batteries, and many other devices and applications. Reduction takes place when an element or radical (an ionic group) gains electrons, such as when a double positive copper ion in solution gains two electrons to form metallic copper. Oxidation takes place when an element or radical loses electrons, such as when a zinc electrode loses two electrons to form a doubly positive zinc ion in solution. In electrochemical research and applications the sites of oxidation and reduction are spatially separated. The electrons produced by chemical processes can be forced to flow through a wire, and this... 

We can now see why batteries have limited lifetimes. As the redox reaction proceeds in the cell just described, the reactants deplete the zinc atoms oxidize and the copper ions reduce. Over time, the zinc electrode dissolves away, and the Cu2+ solution is depleted the battery no longer produces electric current and must be discarded. In a rechargeable batteiy, the recharge cycle uses an external source to force electrons to travel in the opposite direction. The reaction goes in reverse and regenerates the reactants. 

The button configuration of the zinc/mercuric oxide battery is shown in Fig. 11.2. The top is copper or copper alloy on the inner face and nickel or stainless steel on the outer face. This part may also be gold plated, depending on the application. Within the top is a dispersed... 

Like any common batteries, lithium batteries will rupture if exposed to fire. The low-rate lithium batteries, intended for watches, should be safe if used within manufacturers specified temperatures. Thick separators in these low-rate cells prevent shorting and their small size permits easy heat dissipation if any local internal reactions should occur. In fact, a good case can be made that most low-rate lithium cells are safer than zinc-mercury cells, which can introduce poisonous mercury into the atmosphere when incinerated. SAFI supply lithium-copper oxide... 

SAFT supply this type of battery. The particular advantages claim for lithium-copper oxide batteries are long operating life, long shelf life (up to 10 years projected) and high operating temperature (tested between — 20 and - -50°C). Volumetric capacity (Ah/dm ) is 750 compared with 300 for alkaline manganese dioxide, 400 for mercury-zinc and 500 for lithium—sulphur... 

Thus films can be divided into two groups according to their morphology. Discontinuous films are porous, have a low resistance and are formed at potentials close to the equilibrium potential of the corresponding electrode of the second kind. They often have substantial thickness (up to 1 mm). Films of this kind include halide films on copper, silver, lead and mercury, sulphate films on lead, iron and nickel oxide films on cadmium, zinc and magnesium, etc. Because of their low resistance and the reversible electrode reactions of their formation and dissolution, these films are often very important for electrode systems in storage batteries. 

Bluish, shimmering, brittle, relatively reactive metal. Is guite guickly covered with a protective oxide layer, which is why iron is treated with zinc With copper, forms the popular alloy brass, which was already known in antiquity. Used in batteries and as a stabilizer in plastics. Zinc oxide is used as a white pigment Zinc ions are essential to all life forms, e.g., as a component of alcohol dehydrogenase and many other enzymes. Hence human beings (70 kg) carry about 2.3 g (half as much as iron). 

Cadmium, as cadmium oxide, is obtained mainly as a by-product during the processing of zinc-bearing ores and also from the refining of lead and copper from sulfide ores (USPHS 1993). In 1989, the United States produced 1.4 million kg of cadmium (usually 0.6 to 1.8 million kg) and imported an additional 2.7 million kg (usually 1.8 to 3.2 million kg). Cadmium is used mainly for the production of nickel-cadmium batteries (35%), in metal plating (30%), and for the manufacture of pigments (15%), plastics and synthetics (10%), and alloys and miscellaneous uses (10%) (USPHS 1993). 

In these redox reactions, there is a simultaneous loss and gain of electrons. In the oxidation reaction part of the reaction (oxidation half-reaction), electrons are being lost, but in the reduction half-reaction, those very same electrons are being gained. Therefore, in redox reactions there is an exchange of electrons, as reactants become products. This electron exchange may be direct, as when copper metal plates out on a piece of zinc or it may be indirect, as in an electrochemical cell (battery). 

Electrons created in the oxidation reaction at the anode of a voltaic cell flow along an external circuit to the cathode, where they fuel the reduction reaction taking place there. We use the spontaneous reaction between zinc and copper as an example of a voltaic cell here, but you should realize that many powerful redox reactions power many types of batteries, so they re not limited to reactions between copper and zinc. 

During battery discharge, as shown in Figure 1 with the Daniell cell as an example, the electrode (a zinc rod immersed in a zinc sulfate solution) at which the oxidation reaction takes place is called the anode, and is the negative electrode. The other electrode (a copper rod immersed in a copper sulfate solution) at which the reduction reaction takes place is called the cathode and is the positive electrode. The electron flow in the external circuit is from anode to cathode (the current, /, conventionally flows in the opposite direction to that of the electrons), and in the electrolyte phase the ionic flow closes the circuit. The net result of the charge flow round the circuit is the cell reaetion, which is made up of the two half-reactions of charge transfer that describe the chemical changes at the two electrodes. 

The reaction in the lemon battery is the reduction of copper ions (a little bit of copper dissolves from the copper penny in the acidic lemon juice) and the oxidation of zinc into zinc ions—the thermodynamically more stable state. Because the reaction is moving toward a more stable state, it can produce electricity as a voltaic cell. An electrolytic cell is the antithesis of the voltaic cell. In the voltaic cell, a chemical reaction is used to produce electricity. In an electrolytic cell, electricity is used to produce chemistry. A demonstration electrolytic cell can be set up as follows. 

Silver [7440-22-4], Ag, as an active material in electrodes was first used by Volta, but the first intensive study using silver as a storage battery electrode was reported in 1889 (5) using silver oxide—iron and silver oxide—copper combinations. Work on silver oxide—cadmium followed. In the 1940s, the use of a semipermeable membrane combined with limited electrolyte was introduced by Andm in the silver oxide—zinc storage battery. 

Zinc metal is oxidized to zinc ions, and copper ions are reduced to copper metal. The copper cathode becomes depleted of electrons because these are taken up by the copper ions in solution. At the same time the zinc anode has an excess of electrons because the neutral zinc atoms are becoming ionic and liberating electrons in the process. The excess electrons from the anode flow to the cathode. The flow of electrons is the source of external current the buildup of electrons at the anode and the depletion at the cathode constitute a potential difference that persists until the reaction ceases. The reaction comes to an end when either all the copper ions are exhausted from the system or all the zinc metal is dissolved, or an equilibrium situation is reached when both half-cell potentials are equal. If the process is used as a battery, such as a flashlight battery, the battery becomes dead when the reaction ceases. 

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