Charge storage mechanism of alpha-MnO2 in protic and aprotic ionic liquid electrolytes
Artikel i vetenskaplig tidskrift, 2020

In this work we have investigated the charge storage mechanism of MnO2 electrodes in ionic liquid electrolytes. We show that by using an ionic liquid with a cation that has the ability to form hydrogen bonds with the active material (MnO2) on the surface of the electrode, a clear faradaic contribution is obtained. This situation is found for ionic liquids with cations that have a low pKa, i.e. protic ionic liquids. For a protic ionic liquid, the specific capacity at low scan rate rates can be explained by a densely packed layer of cations that are in a standing geometry, with a proton directly interacting through a hydrogen bond with the surface of the active material in the electrode. In contrast, for aprotic ionic liquids there is no interaction and only a double layer contribution to the charge storage is observed. However, by adding an alkali salt to the aprotic ionic liquid, a faradaic contribution is obtained from the insertion of Liþ into the surface of the MnO2 electrode. No effect can be observed when Liþ is added to the protic IL, suggesting that a densely packed cation layer in this case prevent Li-ions from reaching the active material surface.


Simon Lindberg

Chalmers, Fysik, Materialfysik

Steffen Jeschke

Chalmers, Fysik, Materialfysik

Piotr Jankowski

Danmarks Tekniske Universitet (DTU)

Politechnika Warszawska

Muhammad Abdelhamid

Uppsala universitet

Chalmers, Fysik, Materialfysik

T. Brousse

Université de Nantes

Centre national de la recherche scientifique (CNRS)

J. Le Bideau

Université de Nantes

Centre national de la recherche scientifique (CNRS)

Patrik Johansson

Chalmers, Fysik, Materialfysik

Aleksandar Matic

Chalmers, Fysik, Materialfysik

Journal of Power Sources

0378-7753 (ISSN)

Vol. 460 228111


Annan kemi

Den kondenserade materiens fysik



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