Mechanism of Zn Insertion into Nanostructured δ-MnO2: A Nonaqueous Rechargeable Zn Metal Battery

Sang Don Han, Soojeong Kim, Dongguo Li, Valeri Petkov, Hyun Deog Yoo, Patrick J. Phillips, Hao Wang, Jae Jin Kim, Karren L. More, Baris Key, Robert F. Klie, Jordi Cabana, Vojislav R. Stamenkovic, Timothy T. Fister, Nenad M. Markovic, Anthony K. Burrell, Sanja Tepavcevic, John T. Vaughey

Research output: Contribution to journalArticlepeer-review

176 Scopus citations

Abstract

Unlike the more established lithium-ion based energy storage chemistries, the complex intercalation chemistry of multivalent cations in a host lattice is not well understood, especially the relationship between the intercalating species solution chemistry and the prevalence and type of side reactions. Among multivalent metals, a promising model system can be based on nonaqueous Zn2+ ion chemistry. Several examples of these systems support the use of a Zn metal anode, and reversible intercalation cathodes have been reported. This study utilizes a combination of analytical tools to probe the chemistry of a nanostructured δ-MnO2 cathode in association with a nonaqueous acetonitrile-Zn(TFSI)2 electrolyte and a Zn metal anode. As many of the issues related to understanding a multivalent battery relate to the electrolyte-electrode interface, the high surface area of a nanostructured cathode provides a significant interface between the electrolyte and cathode host that maximizes the spectroscopic signal of any side reactions or minor mechanistic pathways. Numerous factors affecting capacity fade and issues associated with the second phase formation including Mn dissolution in heavily cycled Zn/δ-MnO2 cells are presented including dramatic mechanistic differences in the storage mechanism of this couple when compared to similar aqueous electrolytes are noted.

Original languageEnglish
Pages (from-to)4874-4884
Number of pages11
JournalChemistry of Materials
Volume29
Issue number11
DOIs
StatePublished - Jun 13 2017

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