Electrospinning materials processing and applications
Electrospinning materials processing and applications. Li-ion batteries are characterized by high energy density, long life and good energy performance, etc. Due to their properties, they stand out among the available battery technologies as the preferred battery type. In recent years, the development of high-capacity anode materials for Li-ion batteries that meet the power needs of these devices, as well as the technological innovations that have been achieved in portable devices such as telephones, cellular phones and laptops are of great importance.
With recent innovations in foldable electronic device technologies such as foldable displays, implantable medical devices, and wearable electronics, the development of flexible Li-ion batteries and hence flexible electrode materials for use as power sources in these devices is very important. Another study investigated the development of flexible, high-capacity anode materials for foldable Li-ion batteries. For this purpose, silicon/silica/carbon (Si/SiO2/Carbon) composite nanofiber anode materials, which are flexible and pliable with high capacity, have been developed.
Electrospinning materials processing and applications.
Cars. . The lithium storage capacity of anodes (silicon, tin, germanium and their oxides, etc.) made of lithium active materials, which react with lithium ions in the form of alloys and thus have the function of lithium ion storage, is far superior to lithium. Graphite based anodes (375 mAh/g 1 ) are in commercial use today. is long For example, while the theoretical capacity of pure tin, which can act as an anode, is 992 mAh/g-1, for silicon this value can be as high as 4200 mAh/g-1. However, the volume of these active materials with high lithium storage capacity increases sharply during the charging process (incorporation of lithium ions into its structure).
For example, while silicon has a volume expansion of about 400%, tin has a volume expansion of about 300%. Although the volume expansion disappears due to the removal of lithium ions from the structure by the discharge process, structure destruction (sputtering) for the anode is inevitable. The sputtering of the active material that occurs during the charge-discharge process leads to the formation of an unstable solid electrolyte interface (SEI) and the loss of electronic conductivity between the conductive carbon and the lithium active material. Due to the occurrence of these problems in the active material, the battery capacity is not stable and decreases rapidly. In order to avoid these problems in lithium active materials, many studies have recently been made on composite material anodes having various structures.
electrospinning materials processing and applications pdf
Silica was formed in the structure to accommodate the volume expansion that occurs in silicon during discharge processes without damaging the carbon structure. Furthermore, it aims to increase the lifetime of the anode by coating the outer surface of Si/SiO2/Carbon composite nanofibers fabricated with nano-sized amorphous carbon by chemical vapor deposition (CVD). According to battery tests performed on the fabricated anodes, it was found that composite nanofibers (Si/SiO2/carbon composite nanofibers) containing silica have much higher anode life and battery performance than Si/carbon composite nanofibers.
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According to the results of the electrochemical tests, it was also observed that Si/SiO2/carbon composite nanofibers coated with amorphous carbon showed a much longer anode lifetime than that of uncoated amorphous carbon. In the applied battery tests, it was found that the amorphous carbon-coated Si/SiO2/carbon nanofiber composite anodes prepared in this study retained 91.0% of their original capacity after 50 charge-discharge cycles, and the Colombian efficiency was 97.4% .
First, Si/SiO2/PAN composite nanofibers were prepared by electrospinning from a solution composed of Si nanoparticles, a sol-gel solution of tetraethylorthosilicate (TEOS), and polyacrylonitrile (PAN) to fabricate flexible anodes. The produced composite nanofibers were transformed into Si/SiO2/Carbon composite nanofibers after the applied carbonization process. It was observed that the Si/SiO2/carbon composite nanofibers obtained at the end of the carbonization process are fully flexible and even bendable, in contrast to the Si/carbon composite nanofibers that do not have silica in their structure.