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Title: The reaction mechanism of SnSb and Sb thin film anodes for Na-ion batteries studied by X-ray diffraction, 119Sn and 121Sb Mössbauer spectroscopies

The electrochemical reaction of Sb and SnSb anode materials with Na results in the formation of amorphous materials. To understand the resulting phases and electrochemical capacities we studied the reaction products local order using 119Sn and 121Sb Mössbauer spectroscopies in conjunction with measurements performed on model powder compounds of Na-Sn and Na-Sb to further clarify the reactions steps. For pure Sb the discharge (sodiation) starts with the formation of an amorphous phase composed of atomic environments similar to those found in NaSb, and proceeds further by the formation of environments similar to that present in Na3Sb. The reversible reaction takes place during a large portion of the charge process. At full charge the anode material still contains a substantial fraction of Na, which explains the lack of recrystallization into crystalline Sb. The reaction of SnSb yields Na3Sb crystalline phase at full discharge at higher temperatures (65 and 95°C) while the room temperature reaction yields amorphous compounds. The electrochemically-driven, solid-state amorphization reaction occurring at room temperature is governed by the simultaneous formation of Na-coordinated Sn and Sb environments, as monitored by the decrease (increase) of the 119Sn (121Sb) Mössbauer isomer shifts. Overall, the monitoring of the hyperfine parameters enables to correlatemore » the changes in Na content to the individual Sn and Sb local chemical environments.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division
  2. Univ. of Tennessee, Knoxville, TN (United States). Center for Laser Applications; Univ. of Tennessee Space Inst. (UTSI), Tullahoma, TN (United States)
  3. Univ. of Montpellier II, Montpellier (France). Institut Charles Gerhardt
  4. Univ. of Tennessee, Knoxville, TN (United States). Center for Laser Applications
  5. Univ. of Tennessee Space Inst. (UTSI), Tullahoma, TN (United States)
  6. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
  7. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division
Publication Date:
OSTI Identifier:
1159441
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Journal of Power Sources
Additional Journal Information:
Journal Volume: 267; Journal ID: ISSN 0378-7753
Publisher:
Elsevier
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (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 Sodium ion anode; Tin antimony (SnSb); Antimony (Sb); X-ray diffraction (XRD); ¹¹⁹Sn Mössbauer spectroscopy; ¹²¹Sb Mössbauer spectroscopy