First-Principles Study of Molybdenum Chalcogenide Halide Nanowires for Mg-Ion Battery Cathode Application

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• 作者：Pei Shan Emmeline Yeo ; Man-Fai Ng
• 刊名：Chemistry of Materials
• 出版年：2015
• 出版时间：September 8, 2015
• 年：2015
• 卷：27
• 期：17
• 页码：5878-5885
• 全文大小：528K
• ISSN：1520-5002

文摘

Two categories of molybdenum chalcogenide halide nanowires (NWs), (1) Mo₆Ch_6鈥?i>xHa_x, Ch = S or Se, Ha = I, where the unit cell consists of Mo octahedra directly linked together, and (2) Mo₁₂Ch_18鈥?i>xHa_x, where the unit cell consists of two Mo octahedra linked by bridging atoms, were investigated for their performance as cathode materials for Mg-ion battery. Using density functional theory calculations, we found that Mg adsorbs most strongly on pure selenium-based NWs (i.e., Mo₆Se₆ and Mo₁₂Se₁₈), with adsorption sites around the bridging atoms of Mo₁₂Se₁₈ having the most exothermic Mg adsorption energies. We revealed that differences in Mg adsorption energy result from interactions between Mg and Mo₆Ch_6鈥?i>xI_x that are antibonding (unstable), whereas the interactions between Mg and Mo₁₂Ch_18鈥?i>xI_x are bonding (stable). In addition, we calculated the Mg diffusion barriers and specific capacities of the selenium-based NWs and compared them with other state-of-the-art cathode materials. Our results indicate that Mo₆Se₆ NWs could potentially be used as cathode materials for Mg-ion batteries due to their low Mg diffusion barrier.