Research

Electrochemistry of hollandite α-MnO2:Li-ion and Na-ion insertion and Li2O incorporation


Reference:

Tompsett, D.A. and Islam, M.S., 2013. Electrochemistry of hollandite α-MnO2:Li-ion and Na-ion insertion and Li2O incorporation. Chemistry of Materials, 25 (12), pp. 2515-2526.

Related documents:

This repository does not currently have the full-text of this item.
You may be able to access a copy if URLs are provided below. (Contact Author)

Official URL:

http://dx.doi.org/10.1021/cm400864n

Related URLs:

Abstract

MnO2 is attracting considerable interest in the context of rechargeable batteries, supercapacitors, and Li–O2 battery applications. This work investigates the electrochemical properties of hollandite α-MnO2 using density functional theory with Hubbard U corrections (DFT+U). The favorable insertion sites for Li-ion and Na-ion insertion are determined, and we find good agreement with measured experimental voltages. By explicit calculation of the phonons we suggest multiple insertion sites are accessible in the dilute limit. Significant structural changes in α-(Li,Na)xMnO2 during ion insertion are demonstrated by determining the low energy structures. The significant distortions to the unit cell and Mn coordination are likely to be active in causing the observed degradation of α-MnO2 with cycling. The presence of Li2O in the structure reduces these distortions significantly and is the probable cause for the good experimental cycling stability of α-[0.143Li2O]-MnO2. However, the presence of Na2O is less effective in reducing the distortion of the Na-ion intercalated form. We also find a distinct change in the favored Li-ion insertion site, not identified in previous studies, for lithiation of α-LixMnO2 at x > 0.5. The migration barriers for both Li-ions and Na-ions increase from <0.3 eV in the dilute limit to >0.48 eV for α-(Li,Na)0.75MnO2. Finally, the electronic density of states in α-MnO2 with the incorporation of Li2O has the character of a full metal, not a half metal as was suggested in previous work. This may be key to its good performance as a catalyst in Li–O2 batteries.

Details

Item Type Articles
CreatorsTompsett, D.A.and Islam, M.S.
DOI10.1021/cm400864n
Related URLs
URLURL Type
http://www.scopus.com/inward/record.url?scp=84879545484&partnerID=8YFLogxKUNSPECIFIED
DepartmentsFaculty of Science > Chemistry
Research CentresCentre for Sustainable Chemical Technologies
RefereedYes
StatusPublished
ID Code36347

Export

Actions (login required)

View Item