Lithium Sulfur Battery Materials Development and Electrochemical Analysis – Effects of PVDF Based Gel Polymer Electrolyte on Dendrite Formation and Carbon Based Protection Layer on Lithium Sulfur Electrodes
Date Issued
2015
Date
2015
Author(s)
Lai, Bo-Yu
Abstract
This research is dedicating to one of the most promising lithium metal battery, lithium sulfur battery. The development of this kind of lithium metal battery is facing some challenges recently, which can split to two parts. One of them is dendrite growth on the lithium metal negative electrode, which may cause some safety issue, including short-circuited and energy capacity decay. We designed a symmetric cell to in-situ observe dendrite growth when applying a constant current. In order to study the relationship between mechanical strength and dendrite growth, we fabricated the cell with different gel polymer electrolyte with different Young’s modulus. We found that when using the gel polymer electrolyte which Young’s modulus is 0.05548MPa and the current density is 0.1mA/cm2, dendrite would not grow in the first 3000 minutes. We also found that the mechanism of oxidation of lithium metal is very similar to pitting corrosion. When using the electrolyte which diffusivity is lower, the phenomena of pitting corrosion is less apparent. The other part is the dissolution of sulfur electrode. Due to its physic properties, the lithium sulfide would gradually dissolve into the electrolyte. This may cause some energy capacity decay. We add an additional layer into the cell to be a protect layer. This layer could efficiently adsorb the lithium sulfide that dissolved into the solution, reducing the decay rate of the cell. We also mixed MWCNT with carbonized lignin, and found that 50% 900℃ carbonized lignin MWCNT film could make the cell remain 1000mAh/g S capacity after 60 cycles(0.1C).
Subjects
lithium metal
lithium sulfur battery
dendrite
gel polymer electrolyte
lignin
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-104-R02631045-1.pdf
Size
23.32 KB
Format
Adobe PDF
Checksum
(MD5):697bcf1b56952a650d814699f2666108