Cells rechargeable

Other alkaline primary cells couple zinc with oxides of mercury or silver and some even use atmospheric oxygen (zinc—air cell). Frequendy, zinc powder is used in the fabrication of batteries because of its high surface area. Secondary (rechargeable) cells with zinc anodes under development are the alkaline zinc—nickel oxide and zinc—chlorine (see Batteries). 

Unlike the cells above, which are all primary cells, this is a secondary (i.e. rechargeable) cell, and the two poles are composed in the uncharged condition of nickel and cadmium hydroxides respectively. These are each supported on microporous nickel, made by a sintering process, and separated by an absorbent impregnated with electrolyte. The charging reactions are ... 

Primary cells are non rechargeable cells, in which the electrochemical reaction is irreversible. They contain only a fixed amount of the reacting compounds and are discharged only once. If the educts are consumed by discharging, the cell cannot, or should not, be used again. A well-known example of a primary cell is the Daniell element, consisting of zinc and copper. 

It should be noted that the rechargeable cells discussed later have the same construction and differ only in separator type, electrode composition and cathode / anode balance. For comparison, Fig. 3 shows the design of an AA-size lithium cell. The construction with a spirally rolled electrode increases the power output. 

The design of a AA-size alkaline manganese dioxide cell is shown in Fig. 1 (Sec. 3.1). Primary and secondary alkaline batteries are constructed in the same way and can be manufactured on essentially the same machinery. The separator material, electrode formulation, and the Mn02 Zn balance are different. Rechargeable cells are zinc-limited to prevent a discharge beyond the first electron-equivalent of the MnOz reduction. The electrolyte is 7-9 mol L KOH. The electrode reactions are ... 

Q), the cumulative capacity gives the number of primary cells replaced during the life-time of the rechargeable cell. A replacement factor of 20 to 25 is chosen in advertisements as representing a general consumer usage with deep cycling (80 percent DOD). 

Lithium deposited on an anode during a charge is chemically active and reacts with organic electrolytes after deposition. Then, the lithium is consumed during cycling. The cycling efficiency (percent) of a lithium anode (Eff) is basically defined by Eq. (1) [23], where Qp is the amount of electricity needed to plate lithium and <2S is the amount of electricity needed to strip all the plated lithium. As Eff is less than 100 percent, an excess of lithium is included in a practical rechargeable cell to compensate for the consumed lithium. 

In practical cases, however, the excess weight and volume due to the use of alloys may not be very far from those required with pure lithium electrodes, for one generally has to operate with a large amount of excess lithium in rechargeable cells in order to make up for the capacity loss related to the filament growth problem upon cycling. 

Figure 17. Specific energies and energy densities of rechargeable cells. Prepared from data kindly provided by Fujifilm Celltech Co., Ltd. 342],...

With regard to rechargeable cells, a number of laboratory studies have assessed the applicability of the rocking-chair concept to PAN-EC/PC electrolytes with various anode/cathode electrode couples [121-123], Performance studies on cells of the type Li°l PAN-EC/PC-based electrolyte lLiMn20 and carbon I PAN-EC/PC-based electrolyte ILiNi02 show some capacity decline with cycling [121]. For cells with a lithium anode, the capacity decay can be attributed mainly to passivation and loss of lithium by its reaction with... 

Conducting polymers, polyaniline, catalytic activity, PANI/expanded graphite composites, metal-air batteries, primary rechargeable cells. 

Gamburtzev S., Velev O.A., Danin R., Srinivasan S., Appleby A.J. Performance of an improved design of metal hydride/air rechargeable cell . In Batteries for portable application and electric vehicles. C.Holmes, A.Landgrebe ed. Pennington Electroch. Soc, 1997, 726-33. 

Unlike the anode-targeted additives discussed in the preceding part, the additives intended for cathode protection have a much longer history than lithium ion technology itself and were originally developed for rechargeable cells based on lithium metal anodes and various 3.0 V class cathode materials. 

In a systematical study, Golovin et al. investigated a series of metallocene derivatives in terms of their redox potentials, mass transport properties, and chemical and electrochemical stabilities in both electrochemical test cells and commercial-size AA rechargeable cells.Figure 43 shows the complete voltammetric scan of the ferrocene-containing elec-... 

Rechargeable cells with a sulfur cathode, a sodium anode, and a solid electrolyte such as yS-alumina have been much investigated [8[. They are operated at about 618 K, temperature at which sodium and sulfur are both liquid. 

Mn,tCo3 t04) phase. This spinel oxide is broken up during reduction to make MnO t and a metallic surface. Due to the pre-existence of this Mn-M interaction, electronic promotion is much more easily achieved after reduction as well. It is worthwhile to mention that Mn,tCo3 t04 compounds are well studied in the literature, because they have important electrocatalytical properties. More specifically, spinel-type manganese oxides are widely used as precursors in the preparation of X-Mn02 ([ ]A[Mn2]B04], an oxide of technical interest due to its application as a cathode material for rechargeable cells. " ... 

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