Dresden 2014 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 12: Energy materials: Water splitting, batteries, and supercapacitors (with CPP/MM)

HL 12.5: Vortrag

Montag, 31. März 2014, 11:45–12:00, POT 081

First principles study on the electronic properties of NaO₂ — •Markus Heinemann¹, Pascal Hartmann², Conrad L. Bender², Philipp Adelhelm², Jürgen Janek², and Christian Heiliger¹ — ¹I. Physikalisches Institut, Justus Liebig University, 35392 Giessen, Germany — ²Physikalisch-Chemisches Institut, Justus Liebig University, 35392 Giessen, Germany

In the light of the recent discovery of rechargeable room-temperature sodium superoxide (NaO₂) batteries [1], a deeper understanding of the electronic properties of NaO₂ has become of broad interest. We investigate the electronic structure of NaO₂ using the framework of density functional theory and employ a hybrid functional approach for the exchange and correlation interaction. The disordered pyrite structure of the NaO₂ room-temperature phase is modeled by taking into account various superoxide orientations in our computations. Our band structure calculations indicate that NaO₂ is an insulator with an energy band gap in the range of 2 eV and that different superoxide alignments lead to a broadening of the conduction band. We compare our calculations to recent experimental investigations on the conductivity of NaO₂.

[1] P. Hartmann, C. L. Bender, M. Vračar, A. K. Dürr, A. Garsuch, J. Janek, and P. Adelhelm, Nature Mat. 3486, 1 (2012)