BIODEGRADABLE POLYMER ELECTROLYTE FROM CELLULOSE ACETATE FOR LITHIUM ION BATTERY APPLICATION

• Main Author: Kasidi, David
• Format: Theses
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/35397
• Institution: Institut Teknologi Bandung

Nowadays, lithium ion battery is one of the biggest commodities in the world. In general, lithium ion battery consists of cathode, anode, electrolyte, and also conductor. The new development of lithium ion battery is the use of polymer electrolyte as a separator between their cathode and anode. In connection with environmental issue and widely application of lithium ion battery, the biodegradable polymer electrolyte for this material becomes one of attractive research to be developed. In this research, polymer electrolyte has been prepared by blending of acetate cellulose with lithium salt, and then characterized their mechanical properties with tensile tester, conductivity with EIS (Electrochemical Impedance Spectroscopy), and thermal properties with DTA/TGA (Differential Thermal Analysis/Thermo Gravimetric Analysis). The increase of lithium perchlorate (LiClO4) content in the matrix of acetate cellulose tend to increase their mechanical properties, and optimal mechanical property of polymer electrolyte was observed in polymer with LiClO4 content of 15% of LiClO4. Their conductivity increases from 2,28 X 10-6 S/cm to 1,18 X 10-4 S/cm with increasing LiClO4 content from 5 % to 20 %. However, their thermal degradation decrease from 337,5 °C for pure of cellulose acetate to 258,5 °C for polymer electrolyte with LiClO4 content of 15%. In addition, the increase of acetylation degree in cellulose acetate from 2.4 to 2.7 tend to increase their conductivity from 1.31 X 10-5 S/cm to 3.94 X 10-5 S/cm. Polymer electrolyte was prepared by blending of acetate cellulose with various concentration of lithium salt, continued to their biodegradation process in liquid medium with activated sludge during 5, 10, 20, and 30 days, and then characterized by weight loss analysis, functional group analysis with FTIR (Fourier Transform Infrared), crystallinity with XRD (X-Ray Diffraction), and then morphology with SEM (Scanning Electron Microscope). The result showed that the increase of incubation time tends to increase their biodegradability. The increase of LiClO4 content tends to increase biodegradability of polymer electrolyte until LiClO4 content of 15 %, then it is followed by decreasing biodegradability in LiClO4 content of 20 %. Based on functional groups analysis with FTIR (Fourier Transform Infrared) showed that after biodegradation during 30 days was observed the presence of the increase absorption peak at 3420-3450 cm-1 indicating the increase in functional group of – OH, but absorption peak at 1747,51 cm-1 decreases indicating the decrease the functional group of C-O acetyl. These results can be concluded that in biodegradation process has occurred hydrolysis of acetyl content from cellulose acetate. The crystallinity analysis showed that biodegradation process tends to decrease crystallinity from 45 % to 39 %. In addition, morphology analysis with SEM (Scanning Electron Microscope) shows the existence of cavities in the surface of membrane and fractures after the biodegradation process. This proves that biodegradation process has occurred in polymer electrolyte of cellulose acetate. Based on all of analysis, it can be concluded that polymer electrolyte prepared from cellulose acetate with LiClO4 could be proposed as polymer electrolyte for lithium ion battery application.