Lithium-oxygen cells:an analytical model to explain the key features in the discharge voltage profiles

Rinaldi, Ali and Wijaya, Olivia and Hoster, Harry Ernst (2016) Lithium-oxygen cells:an analytical model to explain the key features in the discharge voltage profiles. ChemElectroChem, 3 (11). pp. 1944-1950. ISSN 2196-0216

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Abstract

Sodium-oxygen Lithium-oxygen (Li-O2) cells are popular due to their potentially high energy density. A characteristic fingerprint of a given cell is the voltage profile during constant-current discharge. We suggest that the typical initial dip and the following increase of the voltage result from a temporary increase and slow decrease in the concentration of dissolved superoxide, respectively, feeding into the Nernst equation. The steady-state superoxide concentration decreases as the surface area of the solid precipitation product (Li2O2) increases. Importantly, these products bury the electrochemically active carbon surface. Assuming that the electrochemical step only occurs on bare carbon, the Tafel equation provides an expression for the increasing overpotential as a result of the shrinking effective electrode area. This boils the discharge voltage profile down to the sum of two logarithms, grasping all relevant features in recorded discharge voltage profiles.

Item Type:
Journal Article
Journal or Publication Title:
ChemElectroChem
Additional Information:
This is the peer reviewed version of the following article: Rinaldi, A., Wijaya, O. and Hoster, H. E. (2016), Lithium-Oxygen Cells: An Analytical Model to Explain the Key Features in the Discharge Voltage Profiles. ChemElectroChem. Accepted Author Manuscript. doi:10.1002/celc.201600184 which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/celc.201600184/abstract This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1500/1503
Subjects:
ID Code:
80125
Deposited By:
Deposited On:
21 Jun 2016 08:56
Refereed?:
Yes
Published?:
Published
Last Modified:
23 Oct 2020 03:38