Electrolyte leakage

In most cylindrical carbon—zinc cells, the zinc anode also serves as the container for the cell. The zinc can is made by drawing or extmsion. Mercury [7439-97-6J has traditionally been incorporated in the cell to improve the corrosion resistance of the anode, but the industry is in the process of removing this material because of environmental concerns. Corrosion prevention is especially important in cylindrical cells because of the tendency toward pitting of the zinc can which leads to perforation and electrolyte leakage. Other cell types, such as flat cells, do not suffer as much from this problem. 

However, the reaction with water can be made to be extremely slow. Because the alkaline electrolyte is corrosive toward human tissue as well as toward the materials ia devices, it is more important to have a good seal toward preventing electrolyte leakage ia an alkaline battery than ia a carbon—2iac cell. The formation of a good seal is, however, iacompatible with the formation of a noncondensable gas like hydrogen. 

Solid Electrolyte Systems. Whereas there has been considerable research into the development of soHd electrolyte batteries (18—21), development of practical batteries has been slow because of problems relating to the low conductivity of the soHd electrolyte. The development of an all sohd-state battery would offer significant advantages. Such a battery would overcome problems of electrolyte leakage, dendrite formation, and corrosion that can be encountered with Hquid electrolytes. 

Electrolyte leakage. Tissue discs, prepared from potato tubers as described above, were incubated for 16 h at 25°C between wet filter papers. After incubation, the discs were shaken in 20 ml H2O for another 60 min. One ml of this extract was diluted 30-fold with water, and subjected to conductivity measurements using a HI 8788 apparatus (Hanna Instruments). An increase in conductivity indicates a leakage of electrolytes through lesions in the cell wall caused by enzyme action. Control samples were not incubated, they were shaken in water only. 

Electrolyte leakage due to the action of endogenous enzymes. Extracts from tub ... 

Electrochemical reaction scheme in a hydrogen sensor with a membrane for gas transport and a solid housing to prevent electrolyte leakage. 

A compromise is to add some gelled electrolyte. Commercial cells use a porous polyethylene or polypropylene separator filled with a polymer and gel filling with a liquid electrolyte. They offer improved safety with more resistant to overcharge and less chance for electrolyte leakage. 

The solid polymer electrolyte approach provides enhanced safety, but the poor ambient temperature conductivity excludes their use for battery applications. which require good ambient temperature performance. In contrast, the liquid lithium-ion technology provides better performance over a wider temperature range, but electrolyte leakage remains a constant risk. Midway between the solid polymer electrolyte and the liquid electrolyte is the hybrid polymer electrolyte concept leading to the so-called gel polymer lithium-ion batteries. Gel electrolyte is a two-component system, viz., a polymer matrix... 

Thin-Film Batteries 4473 7.5. Ultrathin Polymer Electrolyte—Leakage 4488... 

Steel CC, Drysdale RB (1988) Electrolyte leakage from plant and fungal tissues and dismption of liposome membranes by a-tomatine. Phytochemistry 27 1025... 

Fig. 4. Effect of gymnopusin (18) on duckweed at concentrations ranging from 50 p,M to 100 p,M. (A) Control (B) 50 p,M (C) 100 p,M. Effects on membrane integrity followed a time course similar to that of electrolyte leakage.

The high reliability and the complete absence of faults such as electrolyte leakage or gas generation make the lithium-iodine solid state battery a particularly suitable device for powering implanted electronic devices, and it is now widely used in the cardiac pacemaker industry. The design and construction of Medtronic Inc, pacemaker batteries are shown in Fig. 9.12. A typical unit, such as the Enertec Alpha 33 , has dimensions of 33.4 mm X 27.4 mm X 7.9 mm, giving a total volume of 6.0 cm3 and a mass of 22 g. The cell has a completely welded construction and uses a specialized... 

The carbon purity is one of the key properties, which must be maintained during all the production process as it will influence the potential window in which the DLC is stable during its use. The presence of impurities and possible oxidation-reduction reactions result in a pressure build up in the DLC cell. Excessive pressure may lead to the opening of the cell with the consequence of electrolyte leakage. The presence of impurities will also accelerate the self-discharge and the aging of the component. A corresponding capacitance decrease and a series resistance increase are also observed. 

Effect of (-)-usnic acid (- -) and (+)-usnic acid (-o-) on electrolyte leakage from cucumber cotyledons. The arrow represents the time when the samples were exposed to 325 pmol m"2 s"1 light. Dashed line represents maximum leakage obtained from boiled samples and leakage from untreated samples are shown (- -). 

Cucumber seedlings (Cucumis sativus Long Green Improved ) were grown in a growth chamber maintained at a temperature of 25°C and a photon flux density (PFPD) of 200 pmol s"1 m 2 continuous illumination. Electrolyte leakage induced by compounds was determined using 4 mm cotyledon discs as described by Kenyon... 

Leaf discs have commonly been used for bioassays to determine if herbicides inhibit photosynthesis (Table 16.2). The simplest leaf-disc bioassay uses small discs cut from fully expanded cucumber or pumpkin cotyledons, floated in the light on a phosphate buffered medium containing suspected photosynthesis inhibitors.115 Qualitatively, if photosynthesis is inhibited, the leaf disc sinks. There are several variations of this method that can provide quantitative data. Evolution of O2 in the test solution can be measured with an oxygen electrode, CO2 induced pH changes colorimetrically determined with bromothymol-blue, or electrolyte leakage monitored with a conductivity meter. Leaf strips, algae, isolated chloroplasts, and duckweed (Lemna minor) have been used as test subjects. Although the bioassays presented in Table 16.2 are fairly easy to perform, few allelochemicals have been tested as possible inhibitors of photosynthesis. Many... 

As pointed out above, bioassay choice is extremely important since different sensitivities and different responses are observed that are dependent on the bioassay specimen. For example, comparison of four bioassay methods for detection of destruxin B, a host-specific toxin produced by Alternaria brassicae, indicated a lack of rapid electrolyte leakage and insensitivity of host protoplasts. However, leaf and pollen bioassays were sensitive to low toxin levels. Pollen germination was the most rapid, sensitive and quantitative bioassay for the toxin. Significant inhibition of Brassica campestris pollen germination and pollen tube growth occurred only 30 min after incubation with 2.5 pg mL 1, and 7.5 pg mL 1 caused total inhibition.3... 

The photosynthetic efficiency mainly depends on the openness of stomata, particularly in C3 crops, while their closure tends to avoid excessive water loss. Abscisic acid (ABA) mediates water loss from the guardian cells of the stomata, which is triggered by a decrease in the water content of the leaf and inhibits leaf expansion. In muskmelon seedlings, ABA could improve the maintenance of the leaf water potential and relative water content, and reduce electrolyte leakage [55]. 

---