THEORETICAL STUDY OF THE MECHANISM OF ELECTRODE DEGRADATION AT THE ELECTRODE-ELECTROLYTE INTERPHASE OF LITHIUM-BASED BATTERY SYSTEM

• Main Author: Rachmad Ramadhan, Erland
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/41508
• Institution: Institut Teknologi Bandung

Li-ion battery cell with the layered nickel oxide-based cathode materials are known to suffer decrease in durability and O2 gas evolution which is followed by decrease in capacity. The decrease in durability and capacity is associated with the cathode degradation which is preceded by the oxidative decomposition of the electrolyte molecule such as Ethylene Carbonate (EC) and the dissolutions of Ni+ ions. Unlike the evolution of O2 gas, the process of oxidative decomposition of EC molecule and the dissolution of Ni+ ions are still not known fundamentally. Therefore, density functional theory-based method is applied so that the understanding of thermodynamics and kinetics on the molecular scale is obtained which is then used to understand the occurrence of LNO cathode degradation in Li-ion battery cell fundamentally. In this research, thermodynamics and kinetics analysis of the reaction of EC molecule on LNO surface and thermodynamics analysis of the Ni+ ions dissolutions on LNO surface process were carried out. Thermodynamics and kinetics analysis of the reaction of EC molecule on LNO surface show that proposed reaction such as physisorption, chemisorption, and ring-opening occurred spontaneously, and the EC molecule is unstable due to reactivity problems in LNO surface. On the contrary, the Ni+ ions dissolutions are difficult to occur in general despite the fact that the presence of decomposed EC molecule able to decrease the energy formation of the Ni+ ions vacancy defects.