Regensburg 2022 – scientific programme

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 15: Materials for Energy Storage (joint session KFM/CPP)

KFM 15.2: Talk

Wednesday, September 7, 2022, 09:50–10:10, H7

Investigation of K-ion Intercalation and Conversion in Layer Transiton Metal Disulfide anode: The case of MoS2 and WS2 — •Yulian Dong, Huaping Zhao, and Yong Lei — Fachgebiet Angewandte Nanophysik, Institut für Physik & IMN MacroNano, Technische Universität Ilmenau, 98693 Ilmenau, Germany

Two-dimensional transition metal dichalcogenides (2D-TMDs) have a unique layered structure characterized by weak interlayer van der Waals interaction and strong in-plane covalent bonding. The structure allows the intercalation of guest species in the interlayer space, which shows impressive properties in potassium-ion batteries (PIBs). Thus, various 2D TMDs, including sulfides (MoS2, SnS2, WS2) and selenide (MoSe2 and VSe2), have been studied as potential anode materials for PIBs. This work compares the intercalation and conversion of K in MoS2 and WS2. Intercalation and conversion process is observed during potassium in MoS2 in a voltage range of 3.0-0.5V and 0.5-0.01V, respectively. By controlling cut-off voltage, the investigation demonstrated high capacities derived from the conversion, but it destroys the 2D diffusion pathways leading to an unstable cycling span. While the K+ storage in WS2 is governed by the intercalation reaction rather than the conversion reaction. It exhibited a low capacity decay rate at both low and high current densities as well as great rate capability.