IMPROVING MECHANICAL PROPERTIES OF SOLID STATE BATTERY (SSB) BY APLLYING FUNCTIONALLY GRADED MATERIAL (FGM)

• Main Author: Saputro, Andy
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/70509
• Institution: Institut Teknologi Bandung

Solid-State Battery (SSB) is classified as a battery technology that has a low potential hazard and high energy storage capacity, compared to conventional lithium-ion batteries which are prone to explosion when a short circuit occurs. However, changes in volume on the SSB can cause mechanical loads that cause high voltage concentrations on the electrodes, electrolytes, and interfaces, thereby creating micro-cracks that increase the electrical resistance and also significantly reduce the performance of the SSB. Functionally Graded Material (FGM) was introduced to replace conventional SSB. FGM is made by mixing electrodes and electrolyte molecules to produce a layer with gradation properties with a gradually changing composition. FGM is a strong candidate to replace conventional SSB because the absence of an interface, high-stress concentration will not occur, thereby avoiding the appearance of cracks, which directly improves the performance of SSB. This study aims to see the potential for improving the mechanical properties of Solid-State Batteries using Functionally Graded Material (FGM). Li1.3Al0.3Ti1.7(PO4)3 (LATP) solid electrolyte specimens mixed with Acetylene Black (AB) were prepared by compaction and sintering processes. The ionic conductivity of the specimens was measured using the Electrochemical Impedance Spectroscopy (EIS) method. Compressive testing is then carried out to obtain the mechanical properties of the specimen. Subsequently, the Finite Element Model of the solid electrolyte was developed, including its cracking behavior based on the traction-separation law by inserting the Cohesive Zone Model (CZM) between the model meshes. The FGM model was developed with 4 different types of composition gradation to see the effect on mechanical properties. Furthermore, the anode-electrolyte-cathode FGM model is simulated with shrinkage-expansion behavior during the charging-discharging process. The simulation results show that the mechanical properties of SSB are significantly improved by applying FGM. The use of FGM in SSB can reduce the stress concentration up to 23% and reduce the number of cracks/failures up to 33%.