cognizancejournal.com Ahmad Suseno et al, Cognizance Journal of Multidisciplinary Studies, Vol.4, Issue.5, May 2024, pg. 243-254 (An Open Accessible, Multidisciplinary, Fully Refereed and Peer Reviewed Journal) ISSN: 0976-7797 Impact Factor: 4.843 Index Copernicus Value (ICV) = 77.57 ©2024, Cognizance Journal, cognizancejournal.com, All Rights Reserved 243 SYNTHESIS OF POLYVINYL ALCOHOL/CHITOSAN COMPOSITE MEMBRANES WITH MESOPOROUS SILICA FILLER AS A CANDIDATE LITHIUM-ION BATTERY SEPARATOR Ahmad Suseno 1 ; Retno Ariadi Lusiana 1 ; Didik Setiyo Widodo 1 ; Yelvin Agustam 1 1 Dept. of Chemistry, Faculty of Science and Mathematics, Universitas Diponegoro, Indonesia Corresponding author's e-mail: suseno@live.undip.ac.id DOI: 10.47760/cognizance.2024.v04i05.022 ABSTRACT: Lithium-ion battery separators play a role in maintaining battery safety and providing a path for ion transfer in the electrolyte. Polyolefin polymers such as polypropylene and polyethylene are the most common basic separator materials and have been commercialized. However, this type of separator has a weakness, namely low ion conductivity because the material is hydrophobic. Therefore, the separator is modified by adding inorganic materials such as mesoporous silica to increase ion conductivity so that battery performance increases. This research aims to synthesize mesoporous silica as a filler in polyvinyl alcohol/chitosan (PVA/CS) composite membranes as a candidate separator for lithium-ion batteries. Mesoporous silica was synthesized using the hydrothermal method. Then, the obtained mesoporous silica was applied as a filler in the PVA/CS mixture membrane using the phase inversion method. The results of FTIR characterization show that the mesoporous silica sample has vibration peaks indicating the presence of siloxane (Si-O-Si) and silanol (Si-OH) groups. Based on the acidity test results, SM11 and SM12 each contain a Lewis acid site, and the same Bronsted site detected in the FTIR absorption peak. Mesoporous silica added to the PVA/CS composite membrane causes a decrease in the resistance value of the material and indicates an increase in the membrane's ability to conduct ions. Apart from that, the addition of mesoporous silica material also reduces the membrane resistance value which has implications for increasing the porosity of the composite membrane. Keywords: Separator, polyvinyl alcohol/chitosan, mesoporous silica