DESIGN AND FABRICATION OF ALL-SOLID-STATE RECHARGEABLE LITHIUM BATTERIES FOR FUTURE APPLICATIONS

摘要

The replacement of organic liquid electrolytes with inorganic solid electrolytes is a challenge to extend the versatility of rechargeable lithium-ion batteries. The safety and operating temperature of batteries are surely enhanced by the thermal stability of solid electrolyte. However, the most desirable feature of solid electrolytes is high mechanical strength. Up to now, almost all the rechargeable batteries have been constructed in a layer-by-layer fashion (2D structures), in which a trade-off relationship exists between the energy density and power density. For fixture energy storage/use applications such as electric vehicles and renewable energy systems, this trade-off relationship should be removed by three dimensional (3D) battery configurations, for example, in which rod-like anodes and cathodes are alternately located. The selfstanding characteristic of solid electrolytes makes it easy to construct 3D structures. So far, we have focused on oxide-based solid electrolytes such as Li_(0.35)La_(0.55)TiO_3 (LLT) and Li_7La_3Zr_2O_(12) (LLZ) due to high lithium-ion conductivity as well as high mechanical strength, and formed their hole-array structures. In the presentation, fabrication of those hole-array structures and evaluation of the all-solid-state batteries using the structured solid electrolytes will be reported.