Battery performance additives

Various additives are used for the Ni-Cd batteries to improve the battery performance. Additives are selected based on their special functions to improve the electrode structure and/or electrode chemical and electrochemical properties. For example, cadmium hydroxide Cd(OH)2 is added to the cathode to prevent phase segregation and to help maintain a single phase of the solid solution during the transfer between Ni(OH)2 and NiOOH in charge and discharge processes. Because Cd(OH)2 is isomorphous with both Ni(OH)2 and NiOOH, this structural functionality can improve the cycle life of the battery. Cd or CdO can increase the overpotential of oxygen evolution... 

Table 6.6 presents the individual tests of the NES2 battery. Motor ability, focused attention, selective attention, acquisition, and memory categories of tasks are included in this battery, in addition to a variety of other tasks. The battery is made up of separate tasks performance on combinations of these tasks is potentially altered by exposure to neurotoxic agents such as pesticides, solvents, or carbon monoxide. Many of the tasks are suitable for repeated testing of any individual. Five of the tests are similar to the core tests of the WHO battery.50... 

In modem commercial lithium-ion batteries, a variety of graphite powder and fibers, as well as carbon black, can be found as conductive additive in the positive electrode. Due to the variety of different battery formulations and chemistries which are applied, so far no standardization of materials has occurred. Every individual active electrode material and electrode formulation imposes special requirements on the conductive additive for an optimum battery performance. In addition, varying battery manufacturing processes implement differences in the electrode formulations. In this context, it is noteworthy that electrodes of lithium-ion batteries with a gelled or polymer electrolyte require the use of carbon black to attach the electrolyte to the active electrode materials.49-54 In the following, the characteristic material and battery-related properties of graphite, carbon black, and other specific carbon conductive additives are described. 

POSITIVE-PLATE ADDITIVES TO ENHANCE FORMATION AND BATTERY PERFORMANCE... 

With these two models a battery can be designed, modelled, and optimized for the use of inert additives. Since each type of additive has different effects on battery performance, it is necessary to design the battery to utilize the selected additive to its fullest. The models are also very useful in designing experiments to test the effects that the additives will have on battery performance. 

In the early 1950s, the United States National Bureau of Standards evaluated a battery electrolyte additive which contained sodium sulfate and magnesium sulfate. The manufacturer s claim was that the additive could restore the performance of... 

One of the most successful applications of phosphoric acid has been in gelled electrolytes that are made by adding fumed silica to sulfuric acid [73,74]. Larger phosphate concentrations appear to be tolerated in the gelled acid without adversely affecting cell performance. One reason may be that the plates in these batteries are formed by the dry-charge process and the phosphate is added to the battery with the electrolyte. Addition of silica may also affect the equilibria of phosphate dissociation and/or lead phosphate formation. Further study of these effects may lead to a better understanding of how to control phosphate activities to enhance battery performance. 

Initial measurements carried out on PEO-alkali metal salt complexes indicated that the observed conductivities were mostly ionic with little contribution from electrons. It should be noted that the ideal electrolyte for lithium rechargeable batteries is a purely ionic conductor and, furthermore, should only conduct lithium ions. Contributions to the conductivity from electrons reduces the battery performance and causes self-discharge on storage. Salts with large bulky anions are used in order to reduce ion mobility, since contributions to the conductivity from anions produces a concentration gradient that adds an additional component to the resistance of the electrolyte. 

Additives should be chemically, thermally and electrochemically stable in H2SO4 solutions for prolonged periods of time, and also have low cost. Electrolyte additives can be classified into three groups (a) inorganic compounds, (b) carbons and (c) polymer emulsions. A brief overview of the most widely used electrolyte additives and of their specific influence on battery performance will be made further in this chapter. 

Recently, different polymer materials have attracted attention as possible additives to sulfuric acid electrolyte aimed to improve battery performance and to meet the ever-increasing demands for specific power and cycle bfe performance of lead—acid batteries. 

Mass and volume reduction to increase capacity and energy density is the key objective in current battery performance, particularly for transport applications. In addition to the increasingly difficult... 

High-performance secondary batteries better than the lithium-ion secondary batteries have not been developed yet. We think that the lithium-ion secondary battery will become widely available and its application expanded. In addition, demands for the improvement of battery performance will drive the creation of miniaturized, thinner, higher capacity, and safer batteries. These performances are translated into, for example, facilitation in manufacturing electrode paint, speedup of electrode manufacture, high-speed impregnation of electrolytes to electrodes, and high-speed... 

The additives eliminate the fire danger in lithium-ion battery without affecting battery performance adversely even though previous additives have contributed to... 

The battery performance using natural graphite as an anode is often poor due to the reaction with the electrolyte to produce a highly resistive SET Special selected compounds such as vinyl acetate (VA), divinyl adipate (ADV), and allyl methyl carbonate (AMC) dissolved in an ordinary electrolyte are presented here to find the effectiveness of the additives. " Figure 19.11 shows the discharge capacity with cycles of positive active materials with and without the special functional additives compared to well-known ethylene sulfite (ES) additive. 

This indicates that the amount of the additive gives a big effect for the battery performance... 

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