Density Functional Theory Simulations Predict New Materials for Magnesium-Ion Batteries (Fact Sheet), NREL Highlights, Science

关键词: ATOMS;    BORON;    DESIGN;    ENERGY DENSITY;    FUNCTIONALS;    HEXAGONAL LATTICES;    MAGNESIUM;    MAGNESIUM BORIDES;    MORPHOLOGY;    NATIONAL RENEWABLE ENERGY LABORATORY;    TRANSFORMATIONS;    TRANSITION ELEMENTS;    VALENCE;    MAGNESIUM IONS;    ELECTRIC BATTERIES MG-ION BATTERIES;    DENSITY FUNCTIONAL SIMULATIONS;    MULTIVALENCE;    Chemical and Material Sciences;   

DOI  :  10.2172/1027687
RP-ID  :  NREL/FS-5900-52004
PID  :  OSTI ID: 1027687
Others  :  TRN: US201123%%332

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来源: SciTech Connect

【 摘 要 】

Multivalence is identified in the light element, B, through structure morphology. Boron sheets exhibit highly versatile valence, and the layered boron materials may hold the promise of a high-energy-density magnesium-ion battery. Practically, boron is superior to previously known multivalence materials, especially transition metal compounds, which are heavy, expensive, and often not benign. Based on density functional theory simulations, researchers at the National Renewable Energy Laboratory (NREL) have predicted a series of stable magnesium borides, MgB{sub x}, with a broad range of stoichiometries, 2 < x < 16, by removing magnesium atoms from MgB{sub 2}. The layered boron structures are preserved through an in-plane topological transformation between the hexagonal lattice domains and the triangular domains. The process can be reversibly switched as the charge transfer changes with Mg insertion/extraction. The mechanism of such a charge-driven transformation originates from the versatile valence state of boron in its planar form. The discovery of these new physical phenomena suggests the design of a high-capacity magnesium-boron battery with theoretical energy density 876 mAh/g and 1550 Wh/L.