ENGINEERING SOLID ELECTROLYTE/ELECTRODE INTERFACES FOR ALL SOLID-STATE LITHIUM-ION BATTERY

Abstract

Nowadays, most commercialized portable electronic devices, such as cell-phones and laptops, use Li-ion batteries as their power source. Li-ion batteries are also being used by automotive companies to power electric vehicles (EVs). However, there is a strong need to make Li-ion batteries safer under abusive conditions, such as car accidents. To address this need, significant research has been recently conducted to utilize solid electrolytes in Li-ion battery cells for the next generation EV applications. In this study, I investigated several solid electrolyte and electrode materials to seek their optimal combinations in terms of chemical stabilities at electrolyte – electrode interfaces. The objective of this study is finding governing parameters that stabilize the interfaces and offer unhindered Li-ion transportations across the interfaces. Among various ceramic electrolyte materials, I selected Li1+xAlxTi2−x(PO4)3 (LATP) based on its good chemical stability in air and moisture. First, I synthesized the LATP powder by using sol-gel method, followed by sintering at 850oC for 5 h in air. The phase purity and particle morphology were characterized, respectively, by using X-ray diffractometer (XRD) and scanning electron microscopy (SEM). I investigated high-temperature stability between cathode materials and LATP by sintering their mixture in a range of 600oC – 900oC. The resulting powders were measured by XRD to identify their phase stabilities. This high-temperature sintering process is a necessary step for a fabrication of the solid-state batteries. Then, I examined electrochemical properties of the LATP – cathode composite by using coin-cells. In this presentation, I will discuss the effect of interfacial stabilities (i.e., LATP – cathode) on the physical and electrochemical properties.