Efficiency, coulombic

The performance of a battery is often designed to be limited by one electrode ia order to achieve special performance characteristics, such as overcharge protection and safety. The coulombic efficiency of the active mass is of particular iaterest ia battery design and performance. 

The addition of some metal ions, such as Mg2+,Zn2+, In3+,orGa3+, and some organic additives, such as 2-thiophene, 2-methylfuran, or benzene, to propylene carbonate-LiC104 improved the coulombic efficiency for lithium cycling [112]. Lithium deposition on a lithium surface covered with a chemically stable, thin and tight layer which was formed by the addition of HF to electrolyte can suppress the lithium dendrite formation in secondary lithium batteries [113]. 

Zinc is electrodeposited from the sodium zincate electrolyte during charge. As in the zinc/bromine battery, two separate electrolytes loops ("posilyte" and "nega-lyte") are required. The only difference is the quality of the separator The zinc/ bromine system works with a microporous foil made from sintered polymer powder, but the zinc/ferricyanide battery needs a cation exchange membrane in order to obtain acceptable coulombic efficiencies. The occasional transfer of solid sodium ferrocya-nide from the negative to the positive tank, to correct for the slow transport of complex cyanide through the membrane, is proposed [54],... 

However, under these conditions, the energy density is lower than with the (CH> ), electrode, whereas, on the other hand, the coulombic efficiencies attain values of 98 %. In some cases PA in its n-doped form has also been used as battery anode (cell type 3) 190,191,241) -j-jjg discharging reaction in a cell with a TiS2 cathode is as follows ... 

The first cell has the maximum capacity of 108 A h kg" and the energy density of 111 W h kg" The coulombic efficiency was close to 100% over at least 2000 complete cycles when cycled between 1.35 V and 0.5 V at a constant current density of 1 mA cm". The second cell also showed excellent recyclability (4000 cycles with 95% coulombic efficiency), on the other hand the discharge capacity decreased steadily from 40 to 25 A h kg" after 4000 cycles. In PANI batteries with aprotic... 

The quantitative analyses of reaction products due to partial or complete oxidation can be performed by different methods. This type of determination is essential to improve electrode composition. Apart from a decrease in the Coulombic efficiency (see Section 11.2), the formation of partially oxidized products can be deleterious for the DMFC application because some of these products (e.g., formic acid) may be in liquid form and are corrosive. 

One may conclude from all these studies that the loss in fuel utilization and Coulombic efficiency in a DMFC due to methanol crossover is still a major barrier in the development of such types of electrochemical power sources. 

Polythiophene films can be electrochemically cycled from the neutral to the conducting state with coulombic efficiencies in excess of 95% [443], with little evidence of decomposition of the material up to + 1.4 V vs. SCE in acetonitrile [37, 54, 56, 396,400] (the 3-methyl derivative being particularly stable [396]), but unlike polypyrrole, polythiophene can be both p- and n-doped, although the n-doped material has a lower maximum conductivity [444], Cyclic voltammetry shows two sets of peaks corresponding to the p- and n-doping reactions, with E° values at approximately + 1.1 V and — 1.4 V respectively (vs. an Ag+/Ag reference electrode)... 

In the fifth paper of this chapter on cathodes, an investigation of thin-film oxide-hydroxide electrodes containing Cr, Ni, and Co compounds was authored by N. Vlasenko et al. The thin-films were produced by electrochemical deposition from transition metal aqueous fluorine-containing electrolytes onto steel substrates. These thin-films were tested in Li coin cells. Electrochemical activity appears to scale with the amount of fluoride used in the deposition the larger concentration of fluoride in the bath, the greater the capacity. One Ni oxide-hydroxide film electrode showed greater than 175 mAh/g reversible capacity on the 50th cycle with excellent coulombic efficiency. 

The coulombic efficiencies for the destruction were calculated to be as follows (figures in parentheses include the total rate of destruction when direct chemical oxidation by HN03 is included) ... 

A full-scale design that has effectively increased cell power requirements by 50 percent to achieve the required destruction efficiencies in spite of efforts to demonstrate good electrochemical or coulombic efficiency earlier studies of mediated electrochemical oxidation (MEO) processes anticipated this outcome, noting that low coulombic... 

The first is the catalytic efficiency of the electrocatalytic process, which in the case of the electrochemically induced reaction is called coulombic efficiency. It is determined by the number of product molecules formed per electron consumed. In our example, the consumption of 0.02 electrons per molecule indicates a coulombic efficiency of 50 molecules produced per electron consumed. 

---