Abstract
The transport properties and lithium insertion mechanism into the first mixed valence silver-copper oxide AgCuO2 and the B-site mixed magnetic delafossite AgCu0.5Mn0.5O2 were investigated by means of four probes DC measurements combined with thermopower measurements and in situ XRD investigations. AgCuO2 and AgCu0.5Mn0.5O2 display p-type conductivity with Seebeck coefficient of Q=+2.46 and +78.83 μV/K and conductivity values of σ=3.2×10-1 and 1.8×10-4 S/cm, respectively. The high conductivity together with the low Seebeck coefficient of AgCuO2 is explained as a result of the mixed valence state between Ag and Cu sites. The electrochemically assisted lithium insertion into AgCuO2 shows a solid solution domain between x=0 and 0.8Li+ followed by a plateau nearby 1.7 V (vs. Li+/Li) entailing the reduction of silver to silver metal accordingly to a displacement reaction. During the solid solution, a rapid structure amorphization was observed. The delafossite AgCu0.5Mn0.5O2 also exhibits Li+/Ag+ displacement reaction in a comparable potential range than AgCuO2; however, with a prior narrow solid solution domain and a less rapid amorphization process. AgCuO2 and AgCu0.5Mn0.5O2 provide a discharge gravimetric capacity of 265 and 230 mA h/g above 1.5 V (vs. Li+/Li), respectively, with no evidence of a new defined phases.
Original language | English |
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Pages (from-to) | 374-380 |
Number of pages | 7 |
Journal | Journal of Solid State Chemistry |
Volume | 182 |
Issue number | 2 |
DOIs | |
Publication status | Published - Feb 2009 |
Keywords
- Delafossite
- In situ XRD
- Lithium batteries
- Silver-copper mixed oxides
- p-Type semi-conductors
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry