Reducing of Grain Boundary Influences By Hybridization of Inorganic/Polymer Materials for Li-Conductive Solid Electrolyte

摘要

Recently, rechargeable batteries are strongly desired as energy storage systems. In particular, Li-ion batteries have been realized for practical use from consumer use (e.g., smartphone, laptop computer) to large-scaled energy storage devices such as for in/output control of renewable energy and electric vehicle owing to their high-energy-density and cycle performances. However, safety will be the most important demands with the scale of batteries, and many ignition accidents have been reported. 'Solvent-free' all-solid-state batteries exhibit quite high safety and have high-energy-density due to realization of thin-film electrolyte layer without separators. Generally, solid electrolytes are mainly categorized to polymer and inorganic electrolytes. Polymer electrolyte have a sufficient self-standing property, formability of stable interface with electrode and mechanical properties. However, it exhibits relatively low ionic conductivity and Li cation transport number. On the other hand, inorganic electrolyte shows relatively high ionic conductivity, even though it have grain boundary (GB) and be easily broken by external force (e.g. dropping and expansion/contraction with charge-discharge processes). Therefore, in this study, we propose polymer/inorganic hybrid electrolyte for usage of both advantages. Hybrid electrolytes of P(EO/PO) network polymer and two-types of Li_(1.5)Al_(0.5)Ge_(1.5)(PO_4)_3 (LAGP) presence/absence GB resistance were investigated for developing high-performance all-solid-state Li batteries.