skip to main content

Title: Band diagram and rate analysis of thin film spinel LiMn 2O 4 formed by electrochemical conversion of ALD-grown MnO

Nanoscale spinel lithium manganese oxide is of interest as a high-rate cathode material for advanced battery technologies among other electrochemical applications. In this work, the synthesis of ultrathin films of spinel lithium manganese oxide (LiMn 2O 4) between 20 and 200 nm in thickness by room-temperature electrochemical conversion of MnO grown by atomic layer deposition (ALD) is demonstrated. The charge storage properties of LiMn 2O 4 thin films in electrolytes containing Li +, Na +, K +, and Mg 2+ are investigated. A unified electrochemical band-diagram (UEB) analysis of LiMn 2O 4 informed by screened hybrid density functional theory calculations is also employed to expand on existing understanding of the underpinnings of charge storage and stability in LiMn 2O 4. It is shown that the incorporation of Li + or other cations into the host manganese dioxide spinel structure (λ-MnO 2) stabilizes electronic states from the conduction band which align with the known redox potentials of LiMn 2O 4. Furthermore, the cyclic voltammetry experiments demonstrate that up to 30% of the capacity of LiMn 2O 4 arises from bulk electronic charge-switching which does not require compensating cation mass transport. As a result, the hybrid ALD-electrochemical synthesis, UEB analysis, and uniquemore » charge storage mechanism described here provide a fundamental framework to guide the development of future nanoscale electrode materials for ion-incorporation charge storage.« less
Authors:
 [1] ;  [2] ;  [3] ;  [1] ;  [1]
  1. Univ. of Colorado, Boulder, CO (United States)
  2. Leupold-Institut fur Angewandte Naturwissenschaften, Zwickau (Germany)
  3. Univ. of Colorado, Boulder, CO (United States); National Renewable Energy Lab. (NREL), Golden, CO (United States)
Publication Date:
OSTI Identifier:
1333410
Report Number(s):
NREL/JA-5K00-67263
Journal ID: ISSN 1616-301X
Grant/Contract Number:
AC36-08GO28308
Type:
Accepted Manuscript
Journal Name:
Advanced Functional Materials
Additional Journal Information:
Journal Volume: 26; Journal Issue: 43; Journal ID: ISSN 1616-301X
Publisher:
Wiley
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; atomic layer deposition; charge storage mechanism; defect theory; ion intercalation; lithium manganese oxide