Sodium cobalt (III) oxide

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Crystal structure
Lithium cobalt (III) oxide
__ Na +      __ Co 3+      __ O 2−
General
Surname Sodium cobalt (III) oxide
other names
  • Sodium Cobalt Dioxide
  • Sodium cobalt oxide
  • Sodium cobalt oxide
Ratio formula NaCoO 2
Brief description

black solid

External identifiers / databases
CAS number
  • 39455-58-8
  • 595564-41-3 (hydrate)
  • 108159-17-7 (x = 0.6)
  • 118392-28-2 (x = 0.64-0.74)
  • 121091-71-2 (x = 0.67)
  • 153590-08-0 (x = 0.77)
Wikidata Q31841811
properties
Molar mass 113.919 g mol −1
Physical state

firmly

safety instructions
GHS hazard labeling
no classification available
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Sodium cobalt (III) oxide is a chemical compound of sodium , cobalt and oxygen . Cobalt and oxygen form cobalt oxide levels between which sodium ions are embedded.

Manufacturing

Different sodium cobalt (III) oxide phases can be produced by reacting sodium peroxide or sodium hydroxide and cobalt oxide powder at temperatures of 450 to 750 ° C. In order to obtain phases with x equal to 0.60, 0.77 and 1, the temperature should be 550 ° C, for phases in the range between 0.64 and 0.74 at 750 ° C.

The compound can also be obtained by reacting sodium carbonate with cobalt (II, III) oxide at 750 ° C.

properties

Sodium cobalt (III) oxide is a very moisture-sensitive black solid. It conducts heat poorly, but is a good conductor of electricity. The compound has a layered structure in which layers of sodium atoms alternate with layers of cobalt and oxygen. Of the structure comprising a CoO 2 layer in which CoO 6 octahedra each having a cobalt atom coordinated with six oxygen atoms are connected in an edge-sharing manner, the α-type (rhombohedral system), the α'- Type (monoclinic system), the β-type (orthorhombic system) and the γ-type (hexagonal system) discovered. The α'-type has a structure with the space group R 3 m (space group no.166) , γ-type has a structure with the space group P 6 3 / mmc (space group no.194) , Na 0.5 CoO 2 has a structure with the space group Pmmn (space group no. 59) , Na 0.75 CoO 2 has a monoclinic crystal structure with the space group C 2 / m (space group no. 12) . The superconducting hydrate has a hexagonal structure with the space group P 6 3 / mmc . Template: room group / 166 Template: room group / 194 Template: room group / 59 Template: room group / 12Template: room group / 194

application

The regular structure of sodium atoms in the nanometer range makes sodium cobalt oxide a candidate for laptop batteries, more efficient thermoelectric cooling systems or superconductors .

Batteries

Different phases of sodium cobalt oxide show an electrochemical activity and can therefore be used as cathode material for intercalation batteries. In particular, the P2 phase can be reversibly intercalated over a wide range. There are different phase transitions which lead to step-like changes in the potential compared to metallic sodium.

Superconductivity

By substituting a certain proportion of the sodium ions with water, the distance between the cobalt oxide planes can be significantly increased. This leads to superconducting properties of the hydrate of sodium cobalt oxide. Variation of the sodium and water content between the cobalt oxide levels leads to electron doping of the cobalt atoms, which influences the superconducting properties.The hydrate Na 0.3 CoO 2 · 1.3H 2 O shows a maximum transition temperature Tc of 4.3 K.

Thermoelectricity

Sodium cobalt oxide shows pronounced thermoelectric properties. Compared with a conventional thermoelectric ( bismuth telluride ) shows that the Seebeck coefficient of NaCoO 2 is only about half as large - due to its lower electrical resistance, NaCoO 2 is nevertheless interesting for thermoelectric applications. Investigations into the dependence of the thermoelectric properties on the degree of intercalation show a maximum of the Seebeck coefficient at x> 0.5 and temperatures of about 100 K.

Individual evidence

  1. ↑ a b c d Smith L. Holt: Inorganic Syntheses, Volume 22 . John Wiley & Sons, 2009, ISBN 0-470-13288-4 , pp. 56 ( limited preview in Google Book search).
  2. ↑ Guidechem , accessed January 15, 2016.
  3. ↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
  4. ↑ Yuechuan Lei, Xin Li, Lei Liu, Gerbrand Ceder: Synthesis and Stoichiometry of Different Layered Sodium Cobalt Oxides. In: Chemistry of Materials. 26, 2014, p. 5288, doi : 10.1021 / cm5021788 .
  5. ↑ AGH University of Science and Technology: Sodium cobalt oxide as functional material
  6. ↑ a borgan-chemie.ch : Sodium cobalt oxide in batteries, as a coolant or superconductor , accessed on June 5, 2017
  7. ↑ M. Roger, DJP Morris, DA Tennant, MJ Gutmann, JP Goff, J.-U. Hoffmann, R. Feyerherm, E. Dudzik, D. Prabhakaran, AT Boothroyd, N. Shannon, B. Lake, PP Deen: Patterning of sodium ions and the control of electrons in sodium cobaltate. In: Nature. 445, 2007, p. 631, doi : 10.1038 / nature05531 .
  8. ↑ google.com: Patent DE602004008040T2 - sodium cobalt oxide hydrate - Google patent search , accessed on June 5, 2017
  9. ^ University of Wollongong: Crystal growth, magnetism, transport and superconductivity of two dimensional sodium cobalt oxide single crystals , Chen, Dapeng
  10. ↑ K. Takada, H. Sakurai, E. Takayama-Muromachi, F. Izumi, RA Dilanian, T. Sasaki: A New Superconducting Phase of Sodium Cobalt Oxide. In: Advanced Materials. 16, 2004, p. 1901, doi : 10.1002 / adma.200400756 .
  11. ↑ Nur Khairani Samin, Roshidah Rusdi, Norashikin Kamarudin, Norlida Kamarulzaman: Synthesis and Battery Studies of Sodium Cobalt Oxides, NaCoO 2 Cathodes. In: Advanced Materials Research. 545, 2012, p. 185, doi : 10.4028 / www.scientific.net / AMR.545.185 .
  12. ↑ JJ Braconnier, C. Delmas, C. Fouassier, P. Hagenmuller: Electrochemical behavior of the phases NaxCoO2 In: Materials Research Bulletin 12, 1980, pp. 1797-1804, doi : 10.1016 / 0025-5408 (80) 90199-3 .
  13. ^ R. Berthelot, D. Carlier, C. Delmas: Electrochemical investigation of the P2-NaxCoO2 phase diagram In: Nature Materials 1, 2010, pp. 74-80, doi : 10.1038 / nmat2920 .
  14. ↑ K. Takada, H. Sakurai, E. Takayama-Muromachi, F. Izumi, RA Dilanian, T. Sasaki: Superconductivity in two-dimensional CoO2 layers In: Nature 6927, 2003, pp. 53-55, doi : 10.1038 / nature01450 .
  15. ↑ a b c R. E. Schaak, T. Klimczuk, ML Foo, RJ Cava: Superconductivity phase diagram of NaxCoO2 1.3H2O In: Nature 6948, 2003, pp. 527-530, doi : 10.1038 / nature01774 .
  16. ↑ J. Molenda, C. Delmas, P. Dordor, A. Stoklosa: Transport properties of NaxCoO2-y In: Solid State Ionics 12, 1984, pp. 473-477, doi : 10.1016 / 0167-2738 (84) 90180- 2 .
  17. ↑ a b I. Terasaki, Y. Sasago, K. Uchinokura: Large thermoelectric power in NaCo2O4 single crystals In: Physical Review B 56, 1997, pp. R12685-R12687, doi : 10.1103 / PhysRevB.56.R12685 .
  18. ↑ M. Lee, L. Viciu, L. Li, Y. Wang, ML Foo, S. Watauchi, RA Pascal, RJ Cava, NP Ong: Large enhancement of the thermopower in Na (x) CoO2 at high Na doping In: nature materials 5, 2006, pp. 537-540, doi : 10.1038 / nmat1669 .