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Pressure dynamics in metal-oxygen (metal-air) batteries: a case study on sodium superoxide cells

  • Electrochemical reactions in metal–oxygen batteries come along with the consumption or release of gaseous oxygen. We present a novel methodology for investigating electrode reactions and transport phenomena in metal–oxygen batteries by measuring the pressure dynamics in an enclosed gas reservoir above the oxygen electrode. The methodology is exemplified by a room-temperature sodium–oxygen batteryElectrochemical reactions in metal–oxygen batteries come along with the consumption or release of gaseous oxygen. We present a novel methodology for investigating electrode reactions and transport phenomena in metal–oxygen batteries by measuring the pressure dynamics in an enclosed gas reservoir above the oxygen electrode. The methodology is exemplified by a room-temperature sodium–oxygen battery forming sodium superoxide (NaO2) in an electrolyte of diethylene glycol dimethyl ether (diglyme) and sodium trifluoromethanesulfonate (NaOSO2CF3, NaOTf). The experiments are supported by microkinetic simulations with a one-dimensional multiphysics continuum model. During galvanostatic cycling over 30 cycles, a constant oxygen consumption/release rate is observed upon discharge/charge. The number of transferred electrons per oxygen molecule is calculated to 1.01 ± 0.02 and 1.03 ± 0.02 for discharge and charge, respectively, confirming the nature of the oxygen reaction product as superoxide O2–. The same ratio is observed in cyclic voltammetry experiments with low scan rate (<1 mV/s). However, at higher scan rates, the ratio increases as a result of oxygen transport limitations in the electrolyte. We introduce electrochemical pressure impedance spectroscopy (EPIS) for simultaneously analyzing current, voltage, and pressure of electrochemical cells. Pressure recording significantly increases the sensitivity of impedance toward oxygen transport properties of the porous electrode systems. In addition, we report experimental data on the diffusion coefficient and solubility of oxygen in electrolyte solutions as important parameters for the microkinetic models.show moreshow less

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Metadaten
Document Type:Article (unreviewed)
Zitierlink: https://opus.hs-offenburg.de/1516
Bibliografische Angaben
Title (English):Pressure dynamics in metal-oxygen (metal-air) batteries: a case study on sodium superoxide cells
Author:Pascal Hartmann, Daniel GrüblStaff Member, Heino Sommer, Jürgen Janek, Wolfgang G. BesslerStaff MemberORCiDGND, Philipp Adelhelm
Year of Publication:2014
First Page:1461
Last Page:1471
Parent Title (English):Journal of Physical Chemistry C
Volume:118
Issue:3
ISSN:1932-7455 (Online)
ISSN:1932-7447 (Print)
DOI:https://doi.org/10.1021/jp4099478
Language:English
Inhaltliche Informationen
Institutes:Forschung / INES - Institut für nachhaltige Energiesysteme
Fakultät Elektrotechnik und Informationstechnik (E+I) (bis 03/2019)
Institutes:Bibliografie
GND Keyword:Natrium-Ionen-Akkumulator
Formale Angaben
Open Access: Closed Access 
Licence (German):License LogoUrheberrechtlich geschützt