Synthesis of submicron-sized NiPS₃ particles and electrochemical properties as active materials in all-solid-state lithium batteries

• DOI: 10.2109/jcersj2.18011
• Publication Date: 2018-06-30T22:27:23Z
• Authors: Yusaku SUTO; Yuta FUJII; Akira MIURA; Nataly Carolina R...; Mikio HIGUCHI; Kiyoharu TADANAGA
• Keywords: All-solid-state lithium secondary battery; Sulfide; 02 engineering and technology; 0210 nano-technology

Submicron-sized NiPS3 particles were synthesized by heating fine Ni powder (<100 nm), red phosphorus, and sulfur at 673 K for 48 h, and their electrochemical properties as cathodes in sulfide-based all-solid-state lithium batteries were investigated using discharge/charge measurements, X-ray diffraction (XRD) measurements, electrochemical impedance spectroscopy, and X-ray absorption near-edge structure spectroscopy (XANES). Batteries using submicron-sized NiPS3 as a cathode active material exhibited a 10th discharge capacity of 147 mAh g(-1) , which was larger than that obtained with 10-100 micron-sized NiPS3 (similar to 90 mAh g(-1)). The XRD patterns of the composite cathode before and after discharge/charge suggested that Li4P2S6 was formed irreversibly (2NiPS(3) + 4Li(+) + 4e(-) -> Li4P2S6 + 2Ni), and this irreversible reaction would reduce the capacity of the cathode. The XANES spectra suggested the oxidation/reduction of Ni during discharge-charge cycles, but the change in the spectra during the cycles was considerably small if one assumed the oxidation/reduction of Ni2+/Ni-0. (C) 2018 The Ceramic Society of Japan. All rights reserved.