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Electrochemical Supercapacitors for Energy Storage and Delivery
environment, high power operations, or current resistances due to continual
cycling at high frequencies.
A trade-off exists between increasing and decreasing temperatures. An
increase in operating temperature will decrease the resistance contribution
from the electrolyte as a result of improved electrolyte mobility and increased
dissociation; decreasing the operating temperature exerts the opposite effect.
However, high temperature operation causes declines in capacitance and
performance and may upset the positive effect of R ESR reduction.
The temperature effects are even more severe in an ES stack than a single
cell because the surface area to volume ratio of an ES is smaller. Therefore,
heat management design and optimization are important and necessary in
maintaining an ES’s desired performance.
5.2.6 Humidity
ES cells can operate effectively at high levels of humidity. However, storage
humidity during production can have ill effects on ESs. ES cells are usually
shipped in vacuum-packed containers to prevent exposure of cells to moisture. The terminal pins of the cells are susceptible to oxidation and eventually
corrosion due to high levels of humidity over prolonged periods. If an original vacuum pack is opened and not all the cells are used, the package must
be resealed to shield the remaining cells from humidity. Failure to consider
this important storage requirement will lead to oxidation of the pins, reduced
solderability of the pins, and possible damage to the terminal pins. Oxidized
terminations can be removed cautiously with an abrasive emery cloth.
5.3 Single Cell Manufacturing
Fabrication techniques for electrode materials are diverse in the range of
materials available and the synthesis conditions required. These issues must
be determined before production starts. Popular ES electrode materials
include activated carbon; carbon foams, fibers, and nanotubes; and metal
oxides. For detailed information about the synthesis of these materials and
their corresponding technologies, please see Chapter 4.
5.3.1 Electrode Materials
In the current technological state, most commercially available products are
electric double-layer ESs. Their electrodes are manufactured using an identical material, such as a high surface carbon powder, to serve as both anode
and cathode materials. Using carbons as electrode materials is advantageous
because they are widely available, inexpensive, and diverse in both structure
Electrochemical Supercapacitors for Energy Storage and Delivery
environment, high power operations, or current resistances due to continual
cycling at high frequencies.
A trade-off exists between increasing and decreasing temperatures. An
increase in operating temperature will decrease the resistance contribution
from the electrolyte as a result of improved electrolyte mobility and increased
dissociation; decreasing the operating temperature exerts the opposite effect.
However, high temperature operation causes declines in capacitance and
performance and may upset the positive effect of R ESR reduction.
The temperature effects are even more severe in an ES stack than a single
cell because the surface area to volume ratio of an ES is smaller. Therefore,
heat management design and optimization are important and necessary in
maintaining an ES’s desired performance.
5.2.6 Humidity
ES cells can operate effectively at high levels of humidity. However, storage
humidity during production can have ill effects on ESs. ES cells are usually
shipped in vacuum-packed containers to prevent exposure of cells to moisture. The terminal pins of the cells are susceptible to oxidation and eventually
corrosion due to high levels of humidity over prolonged periods. If an original vacuum pack is opened and not all the cells are used, the package must
be resealed to shield the remaining cells from humidity. Failure to consider
this important storage requirement will lead to oxidation of the pins, reduced
solderability of the pins, and possible damage to the terminal pins. Oxidized
terminations can be removed cautiously with an abrasive emery cloth.
5.3 Single Cell Manufacturing
Fabrication techniques for electrode materials are diverse in the range of
materials available and the synthesis conditions required. These issues must
be determined before production starts. Popular ES electrode materials
include activated carbon; carbon foams, fibers, and nanotubes; and metal
oxides. For detailed information about the synthesis of these materials and
their corresponding technologies, please see Chapter 4.
5.3.1 Electrode Materials
In the current technological state, most commercially available products are
electric double-layer ESs. Their electrodes are manufactured using an identical material, such as a high surface carbon powder, to serve as both anode
and cathode materials. Using carbons as electrode materials is advantageous
because they are widely available, inexpensive, and diverse in both structure