[19a-PB1-1~11] 9.5 New functional materials and new phenomena

[19a-PB1-1] Ionic control of magnetic and electronic phase transformation in sulfide

〇Tsuyoshi Takami¹, Tomonari Takeuchi², Toshiharu Fukunaga¹ (1.Kyoto Univ., 2.AIST)

Keywords:Ionic control, magnetic and electronic properties, sulfide

Switching to high-performance, affordable, and durable batteries for energy storage medium is a long-standing challenge. Here, we report magnetic and electronic properties of the Li₂S-FeS composite cathode by using a scanning spreading resistance microscopy, a SQUID, and a magnetic force microscopy. Oxidation and reduction by Li transform the parent Li₈FeS₅ phase into an amorphous phase and a superparamagnetic phase, respectively. Surprisingly, the electronic resistance of the amorphous phase exhibits a relatively low value. The results presented here do advance our fundamental understanding of the conversion reaction in sulfide materials.