Chemical Manipulation Of Intercalation Structure In Metal Sulfides For Their Study Of Magneto-Electronic Behavior

The development and design of low-dimensional functional materials have long driven the advancement of basic research and emerging technologies.Among them,layered materials with unique electronic structures and two-dimensional features can serve as a fundamental framework to obtain more diverse functional intercalation structures,which have become the current focus of research.However,the complex chemical bonding and many-body interactions during the intercalation process have limited the exploration of two-dimensional structures and their properties.Therefore,precise manipulation and construction of intercalation structures in layered materials will effectively promote functionalization research and applications.This thesis focuses on the ion/molecule-intercalated layered metal sulfide materials.By employing controllable chemical preparation methods,the intercalated ionic/molecular types,quantities,and occupancy sites in confined spaces have been manipulated based on different interlayer structures and charge distributions.Combining with surface/interfacial chemistry,the thesis investigates and summarizes the mechanisms of magnetic-electric transport properties induced by interlayered ionic migration,reconstruction,and molecular self-assembly.The main research content can be outlined as follows:1.We study the electrical transport behavior of non-van der Waals layered materials under the synergistic effect of multiple ions in the interlayer space.By constructing two-dimensional ion transport channels using interlayer Ag+"pillars," the layered Li-Ag solid solution can be realized in the AgCrS2 system.This breaks the traditional interlayer octahedral occupancy of Li+in the LiCrS2 system,effectively reducing the activation energy of Li+and promoting interlayer ion transportation.The ionic conductivity of(Li-Ag)CrS2 reaches up to 19.6 mS·cm-1 at room temperature,making it suitable for the preparation of solid-state electrolytes for solid-state lithium batteries.This strategy of constructing ion transport channels through the synergistic effect of multiple ions in a two-dimensional system provides a new approach for designing high-performance new energy materials.2.We have proposed a top-down exflioation strategy to prepare two-dimensional non-van der Waals layered nanomaterials with specific stoichiometry.Through mild electroetching on the active layer guided by controlling the redox potential difference between the interlayered metal elements and tetraalkylammonium cations,a series of two-dimensional structures of ternary metal chalcogenides can be prepared.The Cu0.65NbS2 nanosheeets with superconducting transition at low temperature have been obtained to investigate the effect of interlayer ionic occupation on the electronic structure.The configuration of interlayered ions significantly influences the properties of the two-dimensional system,offering a powerful method for manipulating intercalation structure properties and exploring new low-dimensional systems.3.We construct a Co(Cp)2 molecular monolayer with a honeycomb configuration using the interlayer self-assembly method in the confined two-dimensional space of SnS2,forming a Co(Cp)2/SnS2 organic-inorganic structure.The Co(Cp)2 monolayers exhibit strong two-dimensional ferromagnetic properties at room temperature with the 4 emu·g-1 saturation magnetization.Further studies reveal that the exchange interactions between Co atoms in adjacent Co(Cp)2 molecules are formed through delocalized electrons(from Cp rings and SnS2),promoting the long-range spin order.The intermolecular magnetic exchange mechanism of Co(Cp)2 monolayer provides a new perspective for the study of two-dimensional magnetism.