[19a-E311-1~8] 6.3 Oxide electronics

▲ [19a-E311-6] Highly reversible Li-ion (de)intercalation to metastable β-MoO₃

〇(M1)Shuxin Zhang¹, Takuto Soma¹, Tatsuya Yajima¹, Akira Ohtomo^1,2 (1.Tokyo Tech., 2.MCES)

Keywords:Epitaxial thin film, Li-ion intercalation, Insulator-to-metal transition

Molybdenum trioxide (MoO₃) has received much attention due to its intriguing physical proper-ties and a wide variety of applications including batteries, gas sensors, and catalysts. MoO₃ is often found with two polymorphs: orthorhombic α-MoO₃ with a layered structure and monoclinic β-MoO₃ with a ReO₃-derived distorted structure, both of which are favorable for Li-ion intercalation, while the latter shows relatively high Li-ion mobility. Electrochemical Li-ion intercalation can be utilized for the reversible modulation of physical properties by controlling the carrier density, and further implemented for the investigation of insulator-metal transition. However, it is difficult to grow metastable β-MoO₃ thin films, especially with both single phase and a single orientation. Here we report on epitaxial stabilization and Li-ion electrochemistry of pure α- and β-MoO₃ films, demonstrating perfect phase control by using pulsed laser deposition (PLD) and Li-ion electrochemical cells. We found that β-MoO₃ indicated better reversibility and durability for Li-ion (de)intercalation process compared to α-MoO₃.