Development of Sulfide Solid Electrolytes and Interface Formation Processes for Bulk-Type All-Solid-State Li and Na Batteries

摘要: All-solid-state batteries with inorganic solid electrolytes are recognized as an ultimate goal of rechargeable because their high safety, versatile geometry and good cycle life. Compared to thin-film batteries, increasing the reversible capacity bulk-type all-solid-state using electrode active material particles is difficult contact areas at solid–solid interfaces between electrolyte limited. Sulfide have several advantages conductivity, wide electrochemical window, appropriate mechanical properties such formability, processability, elastic modulus. Li7P3S11 crystal has highest Li+ ion conductivity 1.7 × 10-2 S cm-1 25 °C. It far beyond conventional organic liquid electrolytes. The Na+ 7.4 10-4 achieved for Na3.06P0.94Si0.06S4 cubic structure. Moreover, formation favorable important realizing solid-state batteries. better formability than oxide Consequently, a dense separator closely attached via “room-temperature sintering” sulfides merely by cold pressing without heat treatment. Elastic moduli sulfide smaller that electrolytes, Na2S-P2S5 glass Young’s modulus Li2S-P2S5 Cross-sectional SEM observations positive layer reveal coating on increases interface even minimum volume electrolyte, indicating energy density enhanced. Both surface preparation nanocomposite effective Our approaches form demonstrated.