[KJS] 20th KIM/JIM Symposium Energy Storage Materials

[KJS4] Synthesis and Energy-Related Function of Advanced Complex Hydrides

*Hiroykui Oguchi¹, Sangryun Kim¹, Shin-ichi Orimo¹ (1. Tohoku University)

Keywords:Complex hydide、Fast Li-ion conduction、All-solid-stete Li battery、Interface、Epitaxial ilm

Complex hydrides Mx(M’yHz) have attracted considerable attention as a new class of solid-electrolytes for all-solid-state batteries. For their applications, enhancing Li-ion conductivity of the complex hydrides is of great importance. In addition, understanding the Li-ion conduction mechanisms at the electrode/electrolyte interface is inevitable for reliable operation of the batteries. To develop complex hydrides with high Li-ion conductivity, we have attempted various materials processing. Recently, we stabilized disordered high−temperature phase of a closo−type complex hydride 0.7Li(CB9H10)−0.3Li(CB11H12). This complex hydride exhibited Li superionic conductivity of 6.7 × 10−3 S cm−1 at 25 °C. To apply nano-scale interface designability of epitaxial films to the study of interfacial effects, we established world-first epitaxial film growth method for complex hydrides. The method was pulsed laser deposition (PLD) and Li(BH4)1-xIx films were epitaxially grown. The low-energy infrared laser heating of Li(BH4)1-xIx targets preserved the BH4 structure and overcame the difficulty to form B-H covalent bonds. The obtained films showed high quality suitable to the interface investigation, for example, high crystallinity and Li-ion conductivity exceeding 1.0×10−2 S cm−1 at 423 K, the highest value reported to any hydride and oxide epitaxial films to date.