Journal
CHEMSUSCHEM
Volume 9, Issue 20, Pages 2948-2956Publisher
WILEY-V C H VERLAG GMBH
DOI: 10.1002/cssc.201600702
Keywords
batteries; conversion; intercalation; manganese dioxide; zinc
Funding
- Korea Institute of Science and Technology [KIST-2E26292]
- National Research Foundation of Korea from the Korean government (MISP) [NRF-2011-C1AAA001-0030538]
- Ministry of Science, ICT & Future Planning, Republic of Korea [2E26292] Funding Source: Korea Institute of Science & Technology Information (KISTI), National Science & Technology Information Service (NTIS)
- National Research Foundation of Korea [2011-0030539, 2016-PAL] Funding Source: Korea Institute of Science & Technology Information (KISTI), National Science & Technology Information Service (NTIS)
Ask authors/readers for more resources
The reaction mechanism of -MnO2 having 2x2 tunnel structure with zinc ions in a zinc rechargeable battery, employing an aqueous zinc sulfate electrolyte, was investigated by insitu monitoring structural changes and water chemistry alterations during the reaction. Contrary to the conventional belief that zinc ions intercalate into the tunnels of -MnO2, we reveal that they actually precipitate in the form of layered zinc hydroxide sulfate (Zn-4(OH)(6)(SO4)5H(2)O) on the -MnO2 surface. This precipitation occurs because unstable trivalent manganese disproportionates and is dissolved in the electrolyte during the discharge process, resulting in a gradual increase in the pH value of the electrolyte. This causes zinc hydroxide sulfate to crystallize from the electrolyte on the electrode surface. During the charge process, the pH value of the electrolyte decreases due to recombination of manganese on the cathode, leading to dissolution of zinc hydroxide sulfate back into the electrolyte. An analogous phenomenon is also observed in todorokite, a manganese dioxide polymorph with 3x3 tunnel structure that is an indication for the critical role of pH changes of the electrolyte in the reaction mechanism of this battery system.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available