Abstract
This paper represents the first description of the electrochemical sodium ion intercalation properties of Na2.7Ru4O9 in both nonaqueous and aqueous electrolytes. Na2.7Ru4O 9 was synthesized at 700-850°C by solid-state reaction under Ar flow. It has single, double and triple chains of edge-sharing RuO6 octahedra and one-dimensional tunnels between them parallel to the b-axis, accommodating three different sites of Na1, Na2 and Na3. In an organic electrolyte (1 M NaClO4 in PC), Na2.7Ru4O9 shows three redox peaks in its cyclic voltammogram between 2.8 and 3.9 V vs. Na. In an aqueous (1 M Na2SO4) electrolyte, Na2.7Ru 4O9 exhibits three anodic peaks during the first charge, similar to the behavior observed in the organic electrolyte. However, the three peaks become a single broad peak over the following cycles. Electrochemical data and ex-situ XRD results indicate that once Na ions are removed from the Na 2.7Ru4O9 structure containing the maximum amount of sodium, only a portion (<60%) can be re-intercalated and that the aqueous electrolyte allows a lower reversible capacity than the nonaqueous electrolyte.
Original language | English |
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Pages (from-to) | A897-A900 |
Journal | Journal of the Electrochemical Society |
Volume | 160 |
Issue number | 6 |
DOIs | |
State | Published - 2013 |