The Li-Air batteries which convert the electrochemical reactions of lithium and O₂ into electrical energy have high theoretical gravimetric capacity (3861 mAh/g_Li) that is ten times higher than that of lithium ion batteries (372 mAh/g_c). Its potential to generate high energy density makes it a promising candidate to replace the lithium ion in the electric vehicle applications. To meet the requirements of the electric vehicle applications, the technical barriers that limit the cycle life such as oxygen permeation, electrolyte and cathode instability and low rate capability need to be overcome. Especially the consumption/de-activation of Li metal is accelerated when oxygen in cathode side moves into Li metal side through the electrolyte, which is one of the most significant factors preventing long-term operation of the system.

Ceramic solid state electrolyte (SSE) separator has a remarkable gas blocking capability, but it should be thick and heavy (~0.3 mm) to be used as a gas barrier of Li-Air battery due to fragile property. This leads to a sharp decrease in energy density. We fabricated composite membrane consisting of micron-sized SSE particles arrayed in matrix shape and polymer grid. Here SSE particles and polymer have functions of lithium ion conduction and gas blocking, respectively. Cuboid particles were synthesized using silicon wafer template with cuboid pattern on it in size of 50 ~ 200um.

Interface energy between particle and polymer was controlled by bimodal surface modification for better mechanical strength of membrane. Compared to amorphous particles, composite membrane using cuboid LATP particle has many benefits in high ionic conductivity, uniform thickness, light weight and flexibility. In this presentation, how to fabricate cuboid SSE particles in matrix shape array and characterization of composite membrane using it will be discussed.