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.com
Volume 7
Biosensors Journal
ISSN: 2090-4967
Electrochemistry 2018
June 11-12, 2018
June 11-12, 2018 | Rome, Italy
4
th
International Conference on
Electrochemistry
Advances in non-aqueous oxygen electrochemistry, in connection to developing rechargeable Li and
Na –oxygen batteries
Aurbach D
1
and
Sun Y K
2
1
BINA - Bar-Ilan University, Israel
2
Hanyang University, South Korea
R
echargeable Li-oxygen and Na-oxygen batteries if successful and practical can rival internal combustion engines in terms
of very high energy density and enable highly competitive electrochemical propulsion for electric vehicles. These systems
however, are very problematic. So far, we do not have electrolyte solutions that are stable enough towards the active metals
and also towards the oxygen reduction moieties which are superoxide and peroxide species. These oxide moieties are reactive
towards all relevant polar-aprotic solvents, especially in the presence of Li ions, which are highly electrophilic Lewis acids in
aprotic solutions. Oxygen reduction in the presence of Li ions usually forms solid Li
2
O
2
as a final stable product. We can control
its formation and deposition mechanism through the properties of the electrolyte solutions, as mentioned in the attached
image. We can promote fast Li-peroxide precipitation as thin films on the cathode (bottom-up mechanism) or as thick deposits
(top-down mechanism). There is a dilemma what should be preferred, because fast deposition may mean low retention time for
side reactions (higher stability). Oxidation of Li-peroxide upon charging may require too high over-potentials which endanger
the anodic stability of the electrolyte solutions and cathode materials. We know today to overcome this problem by the use
of catalysis by redox mediators. We developed new solvents that can be better protected against attacks by oxygen reduction
species. We explored alternative anodes which should be less reactive than lithium or sodium metals. In order to explore
properly and optimize electrolyte solutions and cathode materials we developed a newmethodology in which Li or Na –oxygen
cells are explored with bi-compartments cells that completely avoid any chemical communication between the anode and the
cathode side, except Li or Na ions exchange. We will discuss the true practical horizons of these battery systems.
aurbach@mail.biu.ac.ilBiosens J 2018, Volume 7
DOI: 10.4172/2090-4967-C1-003