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Title: Unveiling the Structural Evolution of Ag 1.2Mn 8O 16 under Coulombically Controlled (De)Lithiation

MnO 2 materials are considered promising cathode materials for rechargeable lithium, sodium, and magnesi-um batteries due to their earth abundance and environmental friendliness. One polymorph of MnO 2, α-MnO 2, has 2×2 tunnels (4.6 Å × 4.6 Å) in its structural framework, which provide facile diffusion pathways for guest ions. In this work, a silver ion containing α-MnO 2 (Ag 1.2Mn 8O 16) is examined as a candidate cathode material for Li based batteries. Electro-chemical stability of Ag 1.2Mn 8O 16 is investigated through Coulombically controlled reduction under 2 or 4 molar electron equivalents (e.e.). Terminal discharge voltage remains almost constant under 2 e.e. of cycling, whereas it continuously decreases under repetitive reduction by 4 e.e. Thus, detailed structural analyses were utilized to investigate the structural evolution upon lithiation. Significant increases in lattice a (17.7 %) and atomic distances (~4.8 %) are observed when x in Li xAg 1.2Mn 8O 16 is >4. Ag metal forms at this level of lithiation concomitant with a large structural distortion to the Mn-O framework. In contrast, lattice a only expands by 2.2 % and Mn-O/Mn-Mn distances show minor changes (~1.4 %) at x <2. The structural deformation (tunnel breakage) at x >4 inhibitsmore » the recovery of the original structure, leading to poor cycle stability at high lithiation levels. This report establishes the correlation among local structure changes, amorphization processes, formation of Ag 0 and long term cycle stability for this silver containing α-MnO 2 type material at both low and high lithiation levels.« less
Authors:
ORCiD logo [1] ;  [2] ;  [1] ;  [2] ;  [2] ; ORCiD logo [3] ; ORCiD logo [1] ;  [1]
  1. Stony Brook Univ., Stony Brook, NY (United States)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States)
  3. Stony Brook Univ., Stony Brook, NY (United States); Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
Report Number(s):
BNL-203551-2018-JAAM
Journal ID: ISSN 0897-4756
Grant/Contract Number:
SC0012704
Type:
Accepted Manuscript
Journal Name:
Chemistry of Materials
Additional Journal Information:
Journal Volume: 30; Journal Issue: 2; Journal ID: ISSN 0897-4756
Publisher:
American Chemical Society (ACS)
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
25 ENERGY STORAGE
OSTI Identifier:
1434772

Huang, Jianping, Hu, Xiaobing, Brady, Alexander B., Wu, Lijun, Zhu, Yimei, Takeuchi, Esther S., Marschilok, Amy C., and Takeuchi, Kenneth J.. Unveiling the Structural Evolution of Ag1.2Mn8O16 under Coulombically Controlled (De)Lithiation. United States: N. p., Web. doi:10.1021/acs.chemmater.7b03599.
Huang, Jianping, Hu, Xiaobing, Brady, Alexander B., Wu, Lijun, Zhu, Yimei, Takeuchi, Esther S., Marschilok, Amy C., & Takeuchi, Kenneth J.. Unveiling the Structural Evolution of Ag1.2Mn8O16 under Coulombically Controlled (De)Lithiation. United States. doi:10.1021/acs.chemmater.7b03599.
Huang, Jianping, Hu, Xiaobing, Brady, Alexander B., Wu, Lijun, Zhu, Yimei, Takeuchi, Esther S., Marschilok, Amy C., and Takeuchi, Kenneth J.. 2017. "Unveiling the Structural Evolution of Ag1.2Mn8O16 under Coulombically Controlled (De)Lithiation". United States. doi:10.1021/acs.chemmater.7b03599.
@article{osti_1434772,
title = {Unveiling the Structural Evolution of Ag1.2Mn8O16 under Coulombically Controlled (De)Lithiation},
author = {Huang, Jianping and Hu, Xiaobing and Brady, Alexander B. and Wu, Lijun and Zhu, Yimei and Takeuchi, Esther S. and Marschilok, Amy C. and Takeuchi, Kenneth J.},
abstractNote = {MnO2 materials are considered promising cathode materials for rechargeable lithium, sodium, and magnesi-um batteries due to their earth abundance and environmental friendliness. One polymorph of MnO2, α-MnO2, has 2×2 tunnels (4.6 Å × 4.6 Å) in its structural framework, which provide facile diffusion pathways for guest ions. In this work, a silver ion containing α-MnO2 (Ag1.2Mn8O16) is examined as a candidate cathode material for Li based batteries. Electro-chemical stability of Ag1.2Mn8O16 is investigated through Coulombically controlled reduction under 2 or 4 molar electron equivalents (e.e.). Terminal discharge voltage remains almost constant under 2 e.e. of cycling, whereas it continuously decreases under repetitive reduction by 4 e.e. Thus, detailed structural analyses were utilized to investigate the structural evolution upon lithiation. Significant increases in lattice a (17.7 %) and atomic distances (~4.8 %) are observed when x in LixAg1.2Mn8O16 is >4. Ag metal forms at this level of lithiation concomitant with a large structural distortion to the Mn-O framework. In contrast, lattice a only expands by 2.2 % and Mn-O/Mn-Mn distances show minor changes (~1.4 %) at x <2. The structural deformation (tunnel breakage) at x >4 inhibits the recovery of the original structure, leading to poor cycle stability at high lithiation levels. This report establishes the correlation among local structure changes, amorphization processes, formation of Ag0 and long term cycle stability for this silver containing α-MnO2 type material at both low and high lithiation levels.},
doi = {10.1021/acs.chemmater.7b03599},
journal = {Chemistry of Materials},
number = 2,
volume = 30,
place = {United States},
year = {2017},
month = {12}
}