PMID- 24447260
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20141112
LR  - 20140220
IS  - 1520-5207 (Electronic)
IS  - 1520-5207 (Linking)
VI  - 118
IP  - 7
DP  - 2014 Feb 20
TI  - IR, Raman, and NMR studies of the short-range structures of 0.5Na2S + 0.5[xGeS2 + 
      (1-x)PS(5/2)] mixed glass-former glasses.
PG  - 1943-53
LID - 10.1021/jp4111053 [doi]
AB  - A nonlinear and nonadditive composition-dependent change of the ionic 
      conductivity in mixed glass-former (MGF) glasses when one glass former, such as 
      PS(5/2), is replaced by a second glass former, such as GeS2, at constant alkali 
      modifier concentrations, such as Na2S, is known as the mixed glass-former effect 
      (MGFE). Alkali ion conducting glasses are of particular interest for use as solid 
      electrolytes in alkali-based all-solid-state batteries because sulfide amorphous 
      materials have significantly higher alkali ion conductivities than their oxide 
      glass counterparts. In this study of the ternary MGF system Na2S + GeS2 + 
      PS(5/2), we report the careful structural characterization of these glasses using 
      a combination of vibrational, infrared (IR), Raman, and nuclear magnetic 
      resonance (NMR) spectroscopies. Our measurements of the 0.5Na2S + 0.5[xGeS2 + 
      (1-x)PS(5/2)] MGF system show that this glass system exhibits a strongly negative 
      MGFE and non-Arrhenius ionic conductivities. While this negative MGFE in the 
      Na(+) ion conductivity makes these glasses less attractive for use in solid-state 
      Na batteries, the structural origin of this effect is important to better 
      understand the mechanisms of ion conduction in the glassy state. For these 
      reasons, we have examined the structures of ternary 0.5Na2S + 0.5[xGeS2 + 
      (1-x)PS(5/2)] glasses using Raman, IR, and (31)P MAS NMR spectroscopies. In these 
      studies, it is found that the substitution of PS(5/2) by GeS2, that is, 
      increasing x, leads to unequal sharing of the Na(+) in these glasses. Thus, in 
      all MGF compositions, phosphorus groups are associated with a disproportionately 
      larger fraction, f(Na(P)) > 0.5(1 - x), of the Na(+) ions while the germanium 
      groups are found to be Na(+)-deficient relative to the total amount of Na(+) 
      present in the glass, that is, f(Na(Ge)) < 0.5x. From the spectroscopic study of 
      these glasses, a short-range order (SRO) structural model is developed for these 
      glasses and is based on the germanium and phosphorus SRO groups in these glasses 
      as a first step in understanding the unique negative MGFE and non-Arrhenius 
      behavior in the Na(+) ion conductivity in these glasses.
FAU - Bischoff, Christian
AU  - Bischoff C
AD  - Department of Materials Science and Engineering, Iowa State University of Science 
      & Technology , Ames, Iowa 50011, United States.
FAU - Schuller, Katherine
AU  - Schuller K
FAU - Dunlap, Nathan
AU  - Dunlap N
FAU - Martin, Steve W
AU  - Martin SW
LA  - eng
PT  - Journal Article
DEP - 20140210
PL  - United States
TA  - J Phys Chem B
JT  - The journal of physical chemistry. B
JID - 101157530
EDAT- 2014/01/23 06:00
MHDA- 2014/01/23 06:01
CRDT- 2014/01/23 06:00
PHST- 2014/01/23 06:00 [entrez]
PHST- 2014/01/23 06:00 [pubmed]
PHST- 2014/01/23 06:01 [medline]
AID - 10.1021/jp4111053 [doi]
PST - ppublish
SO  - J Phys Chem B. 2014 Feb 20;118(7):1943-53. doi: 10.1021/jp4111053. Epub 2014 Feb 
      10.