A Study of Mg Intercalation Mechanism of a Prospective Mg Full Cell Design

Wednesday, October 14, 2015: 08:00
102-C (Phoenix Convention Center)
N. Sa (Argonne National Lab), A. K. Burrell (Joint Center for Energy Storage Research (JCESR)), T. L. Kinnibrugh (Argonne National Laboratory), H. Wang (Argonne National Laboratory), B. Key (Joint Center for Energy Storage Research), K. W. Chapman (NECCES at Argonne National Laboratory), J. T. Vaughey (Argonne National Laboratory), D. L. Proffit, P. J. Chupas (NECCES at Argonne National Laboratory), and T. T. Fister (Argonne National Laboratory)
A preliminary prospective full cell design composed of V2O5·xH2O as cathode with a Mg metal as anode is constructed where insertion and de-insertion of magnesium into V2O5·xH2O is fully reversible. An in-depth understanding of the Mg intercalation mechanism is investigated by pair distribution function analysis, x-ray absorption near edge structure (XANES) and 25Mg magic angle spinning (MAS NMR) spectroscopy. Interestingly, Mg intercalation results in the formation of multiple phases with different interlayer spacings. Our findings showed that the interlayer spacing of V2O5·xH2O contracts upon Mg intercalation and expands for de-intercalation. An in-depth MAS NMR reveals the existence of two magnesium environments and more interestingly, magnesium intercalation induced a more well-defined Mg-O environment.